diff --git a/Makefile.in b/Makefile.in
index f5fdcd97aa6..f1b18e8f64b 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -235,6 +235,8 @@ CFG_LIBSYNTAX_$(1) :=$(call CFG_LIB_NAME_$(1),syntax)
 CFG_LIBRUSTPKG_$(1) :=$(call CFG_LIB_NAME_$(1),rustpkg)
 CFG_LIBRUSTDOC_$(1) :=$(call CFG_LIB_NAME_$(1),rustdoc)
 CFG_LIBRUSTUV_$(1) :=$(call CFG_LIB_NAME_$(1),rustuv)
+CFG_LIBGREEN_$(1) :=$(call CFG_LIB_NAME_$(1),green)
+CFG_LIBNATIVE_$(1) :=$(call CFG_LIB_NAME_$(1),native)
 
 EXTRALIB_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),extra)
 STDLIB_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),std)
@@ -243,6 +245,8 @@ LIBSYNTAX_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),syntax)
 LIBRUSTPKG_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),rustpkg)
 LIBRUSTDOC_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),rustdoc)
 LIBRUSTUV_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),rustuv)
+LIBGREEN_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),green)
+LIBNATIVE_GLOB_$(1) :=$(call CFG_LIB_GLOB_$(1),native)
 EXTRALIB_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),extra)
 STDLIB_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),std)
 LIBRUSTC_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),rustc)
@@ -250,12 +254,16 @@ LIBSYNTAX_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),syntax)
 LIBRUSTPKG_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),rustpkg)
 LIBRUSTDOC_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),rustdoc)
 LIBRUSTUV_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),rustuv)
+LIBGREEN_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),green)
+LIBNATIVE_DSYM_GLOB_$(1) :=$(call CFG_LIB_DSYM_GLOB_$(1),native)
 
 EXTRALIB_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,extra)
 STDLIB_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,std)
 LIBRUSTUV_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,rustuv)
 LIBSYNTAX_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,syntax)
 LIBRUSTC_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,rustc)
+LIBNATIVE_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,native)
+LIBGREEN_RGLOB_$(1) :=$(call CFG_RLIB_GLOB,green)
 
 endef
 
@@ -272,9 +280,15 @@ define CHECK_FOR_OLD_GLOB_MATCHES_EXCEPT
 endef
 
 # Same interface as above, but deletes rather than just listing the files.
+ifdef VERBOSE
 define REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT
   $(Q)MATCHES="$(filter-out %$(3),$(wildcard $(1)/$(2)))"; if [ -n "$$MATCHES" ] ; then echo "warning: removing previous" \'$(2)\' "libraries:" $$MATCHES; rm $$MATCHES ; fi
 endef
+else
+define REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT
+  $(Q)MATCHES="$(filter-out %$(3),$(wildcard $(1)/$(2)))"; if [ -n "$$MATCHES" ] ; then rm $$MATCHES ; fi
+endef
+endif
 
 # We use a different strategy for LIST_ALL_OLD_GLOB_MATCHES_EXCEPT
 # than in the macros above because it needs the result of running the
@@ -319,6 +333,22 @@ LIBRUSTUV_CRATE := $(S)src/librustuv/lib.rs
 LIBRUSTUV_INPUTS := $(wildcard $(addprefix $(S)src/librustuv/,          \
                                           *.rs */*.rs))
 
+######################################################################
+# Green threading library variables
+######################################################################
+
+LIBGREEN_CRATE := $(S)src/libgreen/lib.rs
+LIBGREEN_INPUTS := $(wildcard $(addprefix $(S)src/libgreen/,          \
+                                          *.rs */*.rs))
+
+######################################################################
+# Native threading library variables
+######################################################################
+
+LIBNATIVE_CRATE := $(S)src/libnative/lib.rs
+LIBNATIVE_INPUTS := $(wildcard $(addprefix $(S)src/libnative/,          \
+                                          *.rs */*.rs))
+
 ######################################################################
 # rustc crate variables
 ######################################################################
@@ -430,6 +460,16 @@ HLIBRUSTUV_DEFAULT$(1)_H_$(3) = \
 TLIBRUSTUV_DEFAULT$(1)_T_$(2)_H_$(3) = \
   $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2))
 
+HLIBGREEN_DEFAULT$(1)_H_$(3) = \
+  $$(HLIB$(1)_H_$(3))/$(CFG_LIBGREEN_$(3))
+TLIBGREEN_DEFAULT$(1)_T_$(2)_H_$(3) = \
+  $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBGREEN_$(2))
+
+HLIBNATIVE_DEFAULT$(1)_H_$(3) = \
+  $$(HLIB$(1)_H_$(3))/$(CFG_LIBNATIVE_$(3))
+TLIBNATIVE_DEFAULT$(1)_T_$(2)_H_$(3) = \
+  $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBNATIVE_$(2))
+
 # Preqrequisites for using the stageN compiler
 ifeq ($(1),0)
 HSREQ$(1)_H_$(3) = $$(HBIN$(1)_H_$(3))/rustc$$(X_$(3))
@@ -441,6 +481,8 @@ HSREQ$(1)_H_$(3) = \
 	$$(HLIBSYNTAX_DEFAULT$(1)_H_$(3)) \
 	$$(HLIBRUSTC_DEFAULT$(1)_H_$(3)) \
 	$$(HLIBRUSTUV_DEFAULT$(1)_H_$(3)) \
+	$$(HLIBGREEN_DEFAULT$(1)_H_$(3)) \
+	$$(HLIBNATIVE_DEFAULT$(1)_H_$(3)) \
 	$$(MKFILE_DEPS)
 endif
 
@@ -455,7 +497,9 @@ SREQ$(1)_T_$(2)_H_$(3) = \
 	$$(TSREQ$(1)_T_$(2)_H_$(3)) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_STDLIB_$(2)) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_EXTRALIB_$(2)) \
-	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2))
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2)) \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBGREEN_$(2)) \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBNATIVE_$(2))
 
 # Prerequisites for a working stageN compiler and libraries, for a specific target
 CSREQ$(1)_T_$(2)_H_$(3) = \
@@ -470,7 +514,9 @@ CSREQ$(1)_T_$(2)_H_$(3) = \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTC_$(2)) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTPKG_$(2)) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTDOC_$(2)) \
-	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2))
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2)) \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBGREEN_$(2)) \
+	$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBNATIVE_$(2))
 
 ifeq ($(1),0)
 # Don't run the the stage0 compiler under valgrind - that ship has sailed
diff --git a/mk/clean.mk b/mk/clean.mk
index 93af331acfb..c59298d1ecb 100644
--- a/mk/clean.mk
+++ b/mk/clean.mk
@@ -90,6 +90,8 @@ clean$(1)_H_$(2):
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_STDLIB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_EXTRALIB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_LIBRUSTUV_$(2))
+	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_LIBNATIVE_$(2))
+	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_LIBGREEN_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_LIBRUSTC_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(CFG_LIBSYNTAX_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(STDLIB_GLOB_$(2))
@@ -98,6 +100,10 @@ clean$(1)_H_$(2):
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(EXTRALIB_RGLOB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBRUSTUV_GLOB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBRUSTUV_RGLOB_$(2))
+	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBNATIVE_GLOB_$(2))
+	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBNATIVE_RGLOB_$(2))
+	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBGREEN_GLOB_$(2))
+	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBGREEN_RGLOB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBRUSTC_GLOB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBSYNTAX_GLOB_$(2))
 	$(Q)rm -f $$(HLIB$(1)_H_$(2))/$(LIBRUSTPKG_GLOB_$(2))
@@ -124,6 +130,8 @@ clean$(1)_T_$(2)_H_$(3):
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_STDLIB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_EXTRALIB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2))
+	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBGREEN_$(2))
+	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBNATIVE_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTC_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBSYNTAX_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(STDLIB_GLOB_$(2))
@@ -132,6 +140,10 @@ clean$(1)_T_$(2)_H_$(3):
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(EXTRALIB_RGLOB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBRUSTUV_GLOB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBRUSTUV_RGLOB_$(2))
+	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBNATIVE_GLOB_$(2))
+	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBNATIVE_RGLOB_$(2))
+	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBGREEN_GLOB_$(2))
+	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBGREEN_RGLOB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBRUSTC_GLOB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBRUSTC_RGLOB_$(2))
 	$(Q)rm -f $$(TLIB$(1)_T_$(2)_H_$(3))/$(LIBSYNTAX_GLOB_$(2))
diff --git a/mk/dist.mk b/mk/dist.mk
index 264d3105839..9f0f64f4c65 100644
--- a/mk/dist.mk
+++ b/mk/dist.mk
@@ -35,6 +35,9 @@ PKG_FILES := \
       libextra                                 \
       libstd                                   \
       libsyntax                                \
+      librustuv				       \
+      libgreen 				       \
+      libnative 			       \
       rt                                       \
       librustdoc                               \
       rustllvm                                 \
diff --git a/mk/host.mk b/mk/host.mk
index 3ddbd7d69c9..9997384d250 100644
--- a/mk/host.mk
+++ b/mk/host.mk
@@ -25,13 +25,7 @@ define CP_HOST_STAGE_N
 
 $$(HBIN$(2)_H_$(4))/rustc$$(X_$(4)): \
 	$$(TBIN$(1)_T_$(4)_H_$(3))/rustc$$(X_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
 	$$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4)) \
-	$$(HSTDLIB_DEFAULT$(2)_H_$(4)) \
-	$$(HEXTRALIB_DEFAULT$(2)_H_$(4)) \
-	$$(HLIBRUSTUV_DEFAULT$(2)_H_$(4)) \
-	$$(HLIBRUSTC_DEFAULT$(2)_H_$(4)) \
-	$$(HLIBSYNTAX_DEFAULT$(2)_H_$(4)) \
 	| $$(HBIN$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(Q)cp $$< $$@
@@ -39,10 +33,6 @@ $$(HBIN$(2)_H_$(4))/rustc$$(X_$(4)): \
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTC_$(4)) \
 	$$(HLIB$(2)_H_$(4))/$(CFG_LIBSYNTAX_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
-	$$(HSTDLIB_DEFAULT$(2)_H_$(4)) \
-	$$(HEXTRALIB_DEFAULT$(2)_H_$(4)) \
-	$$(HLIBRUSTUV_DEFAULT$(2)_H_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 
 	@$$(call E, cp: $$@)
@@ -55,10 +45,11 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTC_$(4)): \
 
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBSYNTAX_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBSYNTAX_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
 	$$(HSTDLIB_DEFAULT$(2)_H_$(4)) \
 	$$(HEXTRALIB_DEFAULT$(2)_H_$(4)) \
 	$$(HLIBRUSTUV_DEFAULT$(2)_H_$(4)) \
+	$$(HLIBGREEN_DEFAULT$(2)_H_$(4)) \
+	$$(HLIBNATIVE_DEFAULT$(2)_H_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBSYNTAX_GLOB_$(4)),$$(notdir $$@))
@@ -76,7 +67,6 @@ $$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)): \
 
 $$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_STDLIB_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(STDLIB_GLOB_$(4)),$$(notdir $$@))
@@ -98,8 +88,7 @@ $$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)): \
 
 $$(HLIB$(2)_H_$(4))/$(CFG_EXTRALIB_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_EXTRALIB_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
+	$$(HSTDLIB_DEFAULT$(2)_H_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(EXTRALIB_GLOB_$(4)),$$(notdir $$@))
@@ -115,7 +104,6 @@ $$(HLIB$(2)_H_$(4))/$(CFG_EXTRALIB_$(4)): \
 $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTUV_$(4)): \
 	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBRUSTUV_$(4)) \
 	$$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)) \
-	$$(HLIB$(2)_H_$(4))/$(CFG_RUNTIME_$(4)) \
 	| $$(HLIB$(2)_H_$(4))/
 	@$$(call E, cp: $$@)
 	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTUV_GLOB_$(4)),$$(notdir $$@))
@@ -128,6 +116,36 @@ $$(HLIB$(2)_H_$(4))/$(CFG_LIBRUSTUV_$(4)): \
 	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTUV_GLOB_$(4)),$$(notdir $$@))
 	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTUV_RGLOB_$(4)),$$(notdir $$@))
 
+$$(HLIB$(2)_H_$(4))/$(CFG_LIBGREEN_$(4)): \
+	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBGREEN_$(4)) \
+	$$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)) \
+	| $$(HLIB$(2)_H_$(4))/
+	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_GLOB_$(4)),$$(notdir $$@))
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_RGLOB_$(4)),$$(notdir $$@))
+	$$(Q)cp $$< $$@
+	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBGREEN_GLOB_$(4)) \
+		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBGREEN_RGLOB_$(4))) \
+		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBGREEN_DSYM_GLOB_$(4))) \
+	        $$(HLIB$(2)_H_$(4))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_GLOB_$(4)),$$(notdir $$@))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_RGLOB_$(4)),$$(notdir $$@))
+
+$$(HLIB$(2)_H_$(4))/$(CFG_LIBNATIVE_$(4)): \
+	$$(TLIB$(1)_T_$(4)_H_$(3))/$(CFG_LIBNATIVE_$(4)) \
+	$$(HLIB$(2)_H_$(4))/$(CFG_STDLIB_$(4)) \
+	| $$(HLIB$(2)_H_$(4))/
+	@$$(call E, cp: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_GLOB_$(4)),$$(notdir $$@))
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_RGLOB_$(4)),$$(notdir $$@))
+	$$(Q)cp $$< $$@
+	$$(Q)cp -R $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBNATIVE_GLOB_$(4)) \
+		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBNATIVE_RGLOB_$(4))) \
+		$$(wildcard $$(TLIB$(1)_T_$(4)_H_$(3))/$(LIBNATIVE_DSYM_GLOB_$(4))) \
+	        $$(HLIB$(2)_H_$(4))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_GLOB_$(4)),$$(notdir $$@))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_RGLOB_$(4)),$$(notdir $$@))
+
 $$(HBIN$(2)_H_$(4))/:
 	mkdir -p $$@
 
diff --git a/mk/install.mk b/mk/install.mk
index 37eaa6f5216..f81367010ed 100644
--- a/mk/install.mk
+++ b/mk/install.mk
@@ -94,6 +94,10 @@ install-target-$(1)-host-$(2): $$(TSREQ$$(ISTAGE)_T_$(1)_H_$(2)) $$(SREQ$$(ISTAG
 	$$(Q)$$(call INSTALL_LIB,$$(EXTRALIB_RGLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTUV_GLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTUV_RGLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBGREEN_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBGREEN_RGLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBNATIVE_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBNATIVE_RGLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,libmorestack.a)
 
 endef
@@ -109,6 +113,10 @@ install-target-$(1)-host-$(2): $$(CSREQ$$(ISTAGE)_T_$(1)_H_$(2))
 	$$(Q)$$(call INSTALL_LIB,$$(EXTRALIB_RGLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTUV_GLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTUV_RGLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBGREEN_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBGREEN_RGLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBNATIVE_GLOB_$(1)))
+	$$(Q)$$(call INSTALL_LIB,$$(LIBNATIVE_RGLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTC_GLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBSYNTAX_GLOB_$(1)))
 	$$(Q)$$(call INSTALL_LIB,$$(LIBRUSTPKG_GLOB_$(1)))
@@ -149,6 +157,7 @@ install-host: $(CSREQ$(ISTAGE)_T_$(CFG_BUILD_)_H_$(CFG_BUILD_))
 	$(Q)$(call INSTALL_LIB,$(STDLIB_GLOB_$(CFG_BUILD)))
 	$(Q)$(call INSTALL_LIB,$(EXTRALIB_GLOB_$(CFG_BUILD)))
 	$(Q)$(call INSTALL_LIB,$(LIBRUSTUV_GLOB_$(CFG_BUILD)))
+	$(Q)$(call INSTALL_LIB,$(LIBGREEN_GLOB_$(CFG_BUILD)))
 	$(Q)$(call INSTALL_LIB,$(LIBRUSTC_GLOB_$(CFG_BUILD)))
 	$(Q)$(call INSTALL_LIB,$(LIBSYNTAX_GLOB_$(CFG_BUILD)))
 	$(Q)$(call INSTALL_LIB,$(LIBRUSTPKG_GLOB_$(CFG_BUILD)))
@@ -174,6 +183,10 @@ uninstall:
           $(call HOST_LIB_FROM_HL_GLOB,$(EXTRALIB_RGLOB_$(CFG_BUILD))) \
           $(call HOST_LIB_FROM_HL_GLOB,$(LIBRUSTUV_GLOB_$(CFG_BUILD))) \
           $(call HOST_LIB_FROM_HL_GLOB,$(LIBRUSTUV_RGLOB_$(CFG_BUILD))) \
+          $(call HOST_LIB_FROM_HL_GLOB,$(LIBGREEN_GLOB_$(CFG_BUILD))) \
+          $(call HOST_LIB_FROM_HL_GLOB,$(LIBGREEN_RGLOB_$(CFG_BUILD))) \
+          $(call HOST_LIB_FROM_HL_GLOB,$(LIBNATIVE_GLOB_$(CFG_BUILD))) \
+          $(call HOST_LIB_FROM_HL_GLOB,$(LIBNATIVE_RGLOB_$(CFG_BUILD))) \
           $(call HOST_LIB_FROM_HL_GLOB,$(LIBRUSTC_GLOB_$(CFG_BUILD))) \
           $(call HOST_LIB_FROM_HL_GLOB,$(LIBSYNTAX_GLOB_$(CFG_BUILD))) \
           $(call HOST_LIB_FROM_HL_GLOB,$(LIBRUSTPKG_GLOB_$(CFG_BUILD))) \
@@ -237,6 +250,7 @@ install-runtime-target-$(1)-host-$(2): $$(TSREQ$$(ISTAGE)_T_$(1)_H_$(2)) $$(SREQ
 	$(Q)$(call ADB_PUSH,$$(TL$(1)$(2))/$$(STDLIB_GLOB_$(1)),$(CFG_RUNTIME_PUSH_DIR))
 	$(Q)$(call ADB_PUSH,$$(TL$(1)$(2))/$$(EXTRALIB_GLOB_$(1)),$(CFG_RUNTIME_PUSH_DIR))
 	$(Q)$(call ADB_PUSH,$$(TL$(1)$(2))/$$(LIBRUSTUV_GLOB_$(1)),$(CFG_RUNTIME_PUSH_DIR))
+	$(Q)$(call ADB_PUSH,$$(TL$(1)$(2))/$$(LIBGREEN_GLOB_$(1)),$(CFG_RUNTIME_PUSH_DIR))
 endef
 
 define INSTALL_RUNTIME_TARGET_CLEANUP_N
@@ -245,6 +259,7 @@ install-runtime-target-$(1)-cleanup:
 	$(Q)$(call ADB_SHELL,rm,$(CFG_RUNTIME_PUSH_DIR)/$(STDLIB_GLOB_$(1)))
 	$(Q)$(call ADB_SHELL,rm,$(CFG_RUNTIME_PUSH_DIR)/$(EXTRALIB_GLOB_$(1)))
 	$(Q)$(call ADB_SHELL,rm,$(CFG_RUNTIME_PUSH_DIR)/$(LIBRUSTUV_GLOB_$(1)))
+	$(Q)$(call ADB_SHELL,rm,$(CFG_RUNTIME_PUSH_DIR)/$(LIBGREEN_GLOB_$(1)))
 endef
 
 $(eval $(call INSTALL_RUNTIME_TARGET_N,arm-linux-androideabi,$(CFG_BUILD)))
diff --git a/mk/target.mk b/mk/target.mk
index 3c7ffd83d96..64bc6ab3afd 100644
--- a/mk/target.mk
+++ b/mk/target.mk
@@ -94,12 +94,37 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTUV_$(2)): \
 	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTUV_GLOB_$(2)),$$(notdir $$@))
 	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTUV_RGLOB_$(2)),$$(notdir $$@))
 
+$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBGREEN_$(2)): \
+		$$(LIBGREEN_CRATE) $$(LIBGREEN_INPUTS) \
+	        $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_STDLIB_$(2)) \
+		$$(TSREQ$(1)_T_$(2)_H_$(3)) \
+		| $$(TLIB$(1)_T_$(2)_H_$(3))/
+	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_GLOB_$(2)),$$(notdir $$@))
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_RGLOB_$(2)),$$(notdir $$@))
+	$$(STAGE$(1)_T_$(2)_H_$(3)) $$(WFLAGS_ST$(1)) \
+		--out-dir $$(@D) $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_GLOB_$(2)),$$(notdir $$@))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBGREEN_RGLOB_$(2)),$$(notdir $$@))
+
+$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBNATIVE_$(2)): \
+		$$(LIBNATIVE_CRATE) $$(LIBNATIVE_INPUTS) \
+	        $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_STDLIB_$(2)) \
+		$$(TSREQ$(1)_T_$(2)_H_$(3)) \
+		| $$(TLIB$(1)_T_$(2)_H_$(3))/
+	@$$(call E, compile_and_link: $$@)
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_GLOB_$(2)),$$(notdir $$@))
+	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_RGLOB_$(2)),$$(notdir $$@))
+	$$(STAGE$(1)_T_$(2)_H_$(3)) $$(WFLAGS_ST$(1)) \
+		--out-dir $$(@D) $$< && touch $$@
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_GLOB_$(2)),$$(notdir $$@))
+	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBNATIVE_RGLOB_$(2)),$$(notdir $$@))
+
 $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBSYNTAX_$(3)): \
                 $$(LIBSYNTAX_CRATE) $$(LIBSYNTAX_INPUTS) \
 		$$(TSREQ$(1)_T_$(2)_H_$(3))			\
 		$$(TSTDLIB_DEFAULT$(1)_T_$(2)_H_$(3))      \
 		$$(TEXTRALIB_DEFAULT$(1)_T_$(2)_H_$(3)) \
-		$$(TLIBRUSTUV_DEFAULT$(1)_T_$(2)_H_$(3)) \
 		| $$(TLIB$(1)_T_$(2)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
 	$$(call REMOVE_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBSYNTAX_GLOB_$(2)),$$(notdir $$@))
@@ -135,16 +160,13 @@ $$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTC_$(3)):		\
 	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_GLOB_$(2)),$$(notdir $$@))
 	$$(call LIST_ALL_OLD_GLOB_MATCHES_EXCEPT,$$(dir $$@),$(LIBRUSTC_RGLOB_$(2)),$$(notdir $$@))
 
-# NOTE: after the next snapshot remove these '-L' flags
 $$(TBIN$(1)_T_$(2)_H_$(3))/rustc$$(X_$(3)):			\
 		$$(DRIVER_CRATE)				\
-		$$(TSREQ$(1)_T_$(2)_H_$(3)) \
+		$$(SREQ$(1)_T_$(2)_H_$(3)) \
 		$$(TLIB$(1)_T_$(2)_H_$(3))/$(CFG_LIBRUSTC_$(3)) \
 		| $$(TBIN$(1)_T_$(2)_H_$(3))/
 	@$$(call E, compile_and_link: $$@)
-	$$(STAGE$(1)_T_$(2)_H_$(3)) --cfg rustc -o $$@ $$< \
-		-L $$(UV_SUPPORT_DIR_$(2)) \
-		-L $$(dir $$(LIBUV_LIB_$(2)))
+	$$(STAGE$(1)_T_$(2)_H_$(3)) --cfg rustc -o $$@ $$<
 ifdef CFG_ENABLE_PAX_FLAGS
 	@$$(call E, apply PaX flags: $$@)
 	@"$(CFG_PAXCTL)" -cm "$$@"
diff --git a/mk/tests.mk b/mk/tests.mk
index d36e0e44295..882fc7e554f 100644
--- a/mk/tests.mk
+++ b/mk/tests.mk
@@ -14,7 +14,7 @@
 ######################################################################
 
 # The names of crates that must be tested
-TEST_TARGET_CRATES = std extra rustuv
+TEST_TARGET_CRATES = std extra rustuv green native
 TEST_DOC_CRATES = std extra
 TEST_HOST_CRATES = rustpkg rustc rustdoc syntax
 TEST_CRATES = $(TEST_TARGET_CRATES) $(TEST_HOST_CRATES)
@@ -162,6 +162,8 @@ $(info check: android device test dir $(CFG_ADB_TEST_DIR) ready \
                   $(CFG_ADB_TEST_DIR)) \
  $(shell adb push $(TLIB2_T_arm-linux-androideabi_H_$(CFG_BUILD))/$(LIBRUSTUV_GLOB_arm-linux-androideabi) \
                   $(CFG_ADB_TEST_DIR)) \
+ $(shell adb push $(TLIB2_T_arm-linux-androideabi_H_$(CFG_BUILD))/$(LIBGREEN_GLOB_arm-linux-androideabi) \
+                  $(CFG_ADB_TEST_DIR)) \
  )
 else
 CFG_ADB_TEST_DIR=
@@ -187,7 +189,7 @@ check-test: cleantestlibs cleantmptestlogs all check-stage2-rfail
 
 check-lite: cleantestlibs cleantmptestlogs \
 	check-stage2-std check-stage2-extra check-stage2-rpass \
-	check-stage2-rustuv \
+	check-stage2-rustuv check-stage2-native check-stage2-green \
 	check-stage2-rustpkg \
 	check-stage2-rfail check-stage2-cfail check-stage2-rmake
 	$(Q)$(CFG_PYTHON) $(S)src/etc/check-summary.py tmp/*.log
@@ -339,19 +341,20 @@ define TEST_RUNNER
 ifeq ($(NO_REBUILD),)
 STDTESTDEP_$(1)_$(2)_$(3) = $$(SREQ$(1)_T_$(2)_H_$(3)) \
                             $$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_EXTRALIB_$(2)) \
-                            $$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_LIBRUSTUV_$(2))
+                            $$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_LIBRUSTUV_$(2)) \
+                            $$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_LIBGREEN_$(2))
 else
 STDTESTDEP_$(1)_$(2)_$(3) =
 endif
 
 $(3)/stage$(1)/test/stdtest-$(2)$$(X_$(2)):			\
-		$$(STDLIB_CRATE) $$(STDLIB_INPUTS)	\
+		$$(STDLIB_CRATE) $$(STDLIB_INPUTS)		\
 		$$(STDTESTDEP_$(1)_$(2)_$(3))
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(2)_H_$(3)) -o $$@ $$< --test
 
 $(3)/stage$(1)/test/extratest-$(2)$$(X_$(2)):			\
-		$$(EXTRALIB_CRATE) $$(EXTRALIB_INPUTS)	\
+		$$(EXTRALIB_CRATE) $$(EXTRALIB_INPUTS)		\
 		$$(STDTESTDEP_$(1)_$(2)_$(3))
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(2)_H_$(3)) -o $$@ $$< --test
@@ -364,6 +367,18 @@ $(3)/stage$(1)/test/rustuvtest-$(2)$$(X_$(2)):			\
 		-L $$(UV_SUPPORT_DIR_$(2)) \
 		-L $$(dir $$(LIBUV_LIB_$(2)))
 
+$(3)/stage$(1)/test/nativetest-$(2)$$(X_$(2)):			\
+		$$(LIBNATIVE_CRATE) $$(LIBNATIVE_INPUTS)	\
+		$$(STDTESTDEP_$(1)_$(2)_$(3))
+	@$$(call E, compile_and_link: $$@)
+	$$(STAGE$(1)_T_$(2)_H_$(3)) -o $$@ $$< --test
+
+$(3)/stage$(1)/test/greentest-$(2)$$(X_$(2)):			\
+		$$(LIBGREEN_CRATE) $$(LIBGREEN_INPUTS)	\
+		$$(STDTESTDEP_$(1)_$(2)_$(3))
+	@$$(call E, compile_and_link: $$@)
+	$$(STAGE$(1)_T_$(2)_H_$(3)) -o $$@ $$< --test
+
 $(3)/stage$(1)/test/syntaxtest-$(2)$$(X_$(2)):			\
 		$$(LIBSYNTAX_CRATE) $$(LIBSYNTAX_INPUTS)	\
 		$$(STDTESTDEP_$(1)_$(2)_$(3))
@@ -375,7 +390,7 @@ $(3)/stage$(1)/test/rustctest-$(2)$$(X_$(2)):					\
 		$$(COMPILER_CRATE) $$(COMPILER_INPUTS) \
 		$$(SREQ$(1)_T_$(2)_H_$(3)) \
 		$$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_RUSTLLVM_$(2)) \
-                $$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_LIBSYNTAX_$(2))
+		$$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_LIBSYNTAX_$(2))
 	@$$(call E, compile_and_link: $$@)
 	$$(STAGE$(1)_T_$(2)_H_$(3)) -o $$@ $$< --test \
 	    -L "$$(LLVM_LIBDIR_$(2))"
@@ -416,10 +431,10 @@ check-stage$(1)-T-$(2)-H-$(3)-$(4)-exec: $$(call TEST_OK_FILE,$(1),$(2),$(3),$(4
 $$(call TEST_OK_FILE,$(1),$(2),$(3),$(4)): \
 		$(3)/stage$(1)/test/$(4)test-$(2)$$(X_$(2))
 	@$$(call E, run: $$<)
-	$$(Q)$$(call CFG_RUN_TEST_$(2),$$<,$(2),$(3)) $$(TESTARGS)	\
-	--logfile $$(call TEST_LOG_FILE,$(1),$(2),$(3),$(4)) \
-	$$(call CRATE_TEST_EXTRA_ARGS,$(1),$(2),$(3),$(4)) \
-	&& touch $$@
+	$$(Q)$$(call CFG_RUN_TEST_$(2),$$<,$(2),$(3)) $$(TESTARGS) \
+	    --logfile $$(call TEST_LOG_FILE,$(1),$(2),$(3),$(4)) \
+	    $$(call CRATE_TEST_EXTRA_ARGS,$(1),$(2),$(3),$(4)) \
+	    && touch $$@
 endef
 
 define DEF_TEST_CRATE_RULES_arm-linux-androideabi
diff --git a/src/compiletest/compiletest.rs b/src/compiletest/compiletest.rs
index 0fb75b7c8e0..ae7d1a30a84 100644
--- a/src/compiletest/compiletest.rs
+++ b/src/compiletest/compiletest.rs
@@ -13,10 +13,11 @@
 #[allow(non_camel_case_types)];
 #[deny(warnings)];
 
+#[cfg(stage0)] extern mod green;
 extern mod extra;
 
 use std::os;
-use std::rt;
+use std::io;
 use std::io::fs;
 
 use extra::getopts;
@@ -234,7 +235,7 @@ pub fn run_tests(config: &config) {
     // sadly osx needs some file descriptor limits raised for running tests in
     // parallel (especially when we have lots and lots of child processes).
     // For context, see #8904
-    rt::test::prepare_for_lots_of_tests();
+    io::test::raise_fd_limit();
     let res = test::run_tests_console(&opts, tests);
     if !res { fail!("Some tests failed"); }
 }
diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index 4176c6698c9..b22c17fb438 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -757,8 +757,8 @@ fn make_lib_name(config: &config, auxfile: &Path, testfile: &Path) -> Path {
 
 fn make_exe_name(config: &config, testfile: &Path) -> Path {
     let mut f = output_base_name(config, testfile);
-    if !os::EXE_SUFFIX.is_empty() {
-        match f.filename().map(|s| s + os::EXE_SUFFIX.as_bytes()) {
+    if !os::consts::EXE_SUFFIX.is_empty() {
+        match f.filename().map(|s| s + os::consts::EXE_SUFFIX.as_bytes()) {
             Some(v) => f.set_filename(v),
             None => ()
         }
diff --git a/src/driver/driver.rs b/src/driver/driver.rs
index 9402578d552..8e5b6356a0b 100644
--- a/src/driver/driver.rs
+++ b/src/driver/driver.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[cfg(stage0)] extern mod green;
+
 #[cfg(rustpkg)]
 extern mod this = "rustpkg";
 
diff --git a/src/etc/licenseck.py b/src/etc/licenseck.py
index 78d0973fdfe..073322b0815 100644
--- a/src/etc/licenseck.py
+++ b/src/etc/licenseck.py
@@ -76,9 +76,9 @@ exceptions = [
     "rt/isaac/randport.cpp", # public domain
     "rt/isaac/rand.h", # public domain
     "rt/isaac/standard.h", # public domain
-    "libstd/rt/mpsc_queue.rs", # BSD
-    "libstd/rt/spsc_queue.rs", # BSD
-    "libstd/rt/mpmc_bounded_queue.rs", # BSD
+    "libstd/sync/mpsc_queue.rs", # BSD
+    "libstd/sync/spsc_queue.rs", # BSD
+    "libstd/sync/mpmc_bounded_queue.rs", # BSD
 ]
 
 def check_license(name, contents):
diff --git a/src/libextra/arc.rs b/src/libextra/arc.rs
index c1763c37bb5..a411c4e9185 100644
--- a/src/libextra/arc.rs
+++ b/src/libextra/arc.rs
@@ -45,7 +45,7 @@ use sync;
 use sync::{Mutex, RWLock};
 
 use std::cast;
-use std::unstable::sync::UnsafeArc;
+use std::sync::arc::UnsafeArc;
 use std::task;
 use std::borrow;
 
@@ -127,20 +127,6 @@ impl<T:Freeze+Send> Arc<T> {
     pub fn get<'a>(&'a self) -> &'a T {
         unsafe { &*self.x.get_immut() }
     }
-
-    /**
-     * Retrieve the data back out of the Arc. This function blocks until the
-     * reference given to it is the last existing one, and then unwrap the data
-     * instead of destroying it.
-     *
-     * If multiple tasks call unwrap, all but the first will fail. Do not call
-     * unwrap from a task that holds another reference to the same Arc; it is
-     * guaranteed to deadlock.
-     */
-    pub fn unwrap(self) -> T {
-        let Arc { x: x } = self;
-        x.unwrap()
-    }
 }
 
 impl<T:Freeze + Send> Clone for Arc<T> {
@@ -247,22 +233,6 @@ impl<T:Send> MutexArc<T> {
                           cond: cond })
         })
     }
-
-    /**
-     * Retrieves the data, blocking until all other references are dropped,
-     * exactly as arc::unwrap.
-     *
-     * Will additionally fail if another task has failed while accessing the arc.
-     */
-    pub fn unwrap(self) -> T {
-        let MutexArc { x: x } = self;
-        let inner = x.unwrap();
-        let MutexArcInner { failed: failed, data: data, .. } = inner;
-        if failed {
-            fail!("Can't unwrap poisoned MutexArc - another task failed inside!");
-        }
-        data
-    }
 }
 
 impl<T:Freeze + Send> MutexArc<T> {
@@ -503,23 +473,6 @@ impl<T:Freeze + Send> RWArc<T> {
             }
         }
     }
-
-    /**
-     * Retrieves the data, blocking until all other references are dropped,
-     * exactly as arc::unwrap.
-     *
-     * Will additionally fail if another task has failed while accessing the arc
-     * in write mode.
-     */
-    pub fn unwrap(self) -> T {
-        let RWArc { x: x, .. } = self;
-        let inner = x.unwrap();
-        let RWArcInner { failed: failed, data: data, .. } = inner;
-        if failed {
-            fail!("Can't unwrap poisoned RWArc - another task failed inside!")
-        }
-        data
-    }
 }
 
 // Borrowck rightly complains about immutably aliasing the rwlock in order to
@@ -689,22 +642,6 @@ mod tests {
         })
     }
 
-    #[test] #[should_fail]
-    pub fn test_mutex_arc_unwrap_poison() {
-        let arc = MutexArc::new(1);
-        let arc2 = ~(&arc).clone();
-        let (p, c) = Chan::new();
-        do task::spawn {
-            arc2.access(|one| {
-                c.send(());
-                assert!(*one == 2);
-            })
-        }
-        let _ = p.recv();
-        let one = arc.unwrap();
-        assert!(one == 1);
-    }
-
     #[test]
     fn test_unsafe_mutex_arc_nested() {
         unsafe {
diff --git a/src/libextra/comm.rs b/src/libextra/comm.rs
index c3b17fe9964..52b5bedb7ea 100644
--- a/src/libextra/comm.rs
+++ b/src/libextra/comm.rs
@@ -96,7 +96,6 @@ pub fn rendezvous<T: Send>() -> (SyncPort<T>, SyncChan<T>) {
 #[cfg(test)]
 mod test {
     use comm::{DuplexStream, rendezvous};
-    use std::rt::test::run_in_uv_task;
 
 
     #[test]
@@ -124,13 +123,11 @@ mod test {
     #[test]
     fn recv_a_lot() {
         // Rendezvous streams should be able to handle any number of messages being sent
-        do run_in_uv_task {
-            let (port, chan) = rendezvous();
-            do spawn {
-                1000000.times(|| { chan.send(()) })
-            }
-            1000000.times(|| { port.recv() })
+        let (port, chan) = rendezvous();
+        do spawn {
+            1000000.times(|| { chan.send(()) })
         }
+        1000000.times(|| { port.recv() })
     }
 
     #[test]
diff --git a/src/libextra/sync.rs b/src/libextra/sync.rs
index 57a7f38696d..f43329076c8 100644
--- a/src/libextra/sync.rs
+++ b/src/libextra/sync.rs
@@ -19,8 +19,9 @@
 
 
 use std::borrow;
-use std::unstable::sync::{Exclusive, UnsafeArc};
-use std::unstable::atomics;
+use std::unstable::sync::Exclusive;
+use std::sync::arc::UnsafeArc;
+use std::sync::atomics;
 use std::unstable::finally::Finally;
 use std::util;
 use std::util::NonCopyable;
@@ -78,7 +79,7 @@ impl WaitQueue {
 
     fn wait_end(&self) -> WaitEnd {
         let (wait_end, signal_end) = Chan::new();
-        self.tail.send_deferred(signal_end);
+        assert!(self.tail.try_send_deferred(signal_end));
         wait_end
     }
 }
@@ -760,23 +761,21 @@ mod tests {
     fn test_sem_runtime_friendly_blocking() {
         // Force the runtime to schedule two threads on the same sched_loop.
         // When one blocks, it should schedule the other one.
-        do task::spawn_sched(task::SingleThreaded) {
-            let s = Semaphore::new(1);
-            let s2 = s.clone();
-            let (p, c) = Chan::new();
-            let mut child_data = Some((s2, c));
-            s.access(|| {
-                let (s2, c) = child_data.take_unwrap();
-                do task::spawn {
-                    c.send(());
-                    s2.access(|| { });
-                    c.send(());
-                }
-                let _ = p.recv(); // wait for child to come alive
-                5.times(|| { task::deschedule(); }); // let the child contend
-            });
-            let _ = p.recv(); // wait for child to be done
-        }
+        let s = Semaphore::new(1);
+        let s2 = s.clone();
+        let (p, c) = Chan::new();
+        let mut child_data = Some((s2, c));
+        s.access(|| {
+            let (s2, c) = child_data.take_unwrap();
+            do task::spawn {
+                c.send(());
+                s2.access(|| { });
+                c.send(());
+            }
+            let _ = p.recv(); // wait for child to come alive
+            5.times(|| { task::deschedule(); }); // let the child contend
+        });
+        let _ = p.recv(); // wait for child to be done
     }
     /************************************************************************
      * Mutex tests
diff --git a/src/libextra/task_pool.rs b/src/libextra/task_pool.rs
index f0c9833adf8..ba38f876287 100644
--- a/src/libextra/task_pool.rs
+++ b/src/libextra/task_pool.rs
@@ -14,12 +14,9 @@
 /// parallelism.
 
 
-use std::task::SchedMode;
 use std::task;
 use std::vec;
 
-#[cfg(test)] use std::task::SingleThreaded;
-
 enum Msg<T> {
     Execute(proc(&T)),
     Quit
@@ -46,7 +43,6 @@ impl<T> TaskPool<T> {
     /// returns a function which, given the index of the task, should return
     /// local data to be kept around in that task.
     pub fn new(n_tasks: uint,
-               opt_sched_mode: Option<SchedMode>,
                init_fn_factory: || -> proc(uint) -> T)
                -> TaskPool<T> {
         assert!(n_tasks >= 1);
@@ -65,18 +61,8 @@ impl<T> TaskPool<T> {
                 }
             };
 
-            // Start the task.
-            match opt_sched_mode {
-                None => {
-                    // Run on this scheduler.
-                    task::spawn(task_body);
-                }
-                Some(sched_mode) => {
-                    let mut task = task::task();
-                    task.sched_mode(sched_mode);
-                    task.spawn(task_body);
-                }
-            }
+            // Run on this scheduler.
+            task::spawn(task_body);
 
             chan
         });
@@ -99,7 +85,7 @@ fn test_task_pool() {
         let g: proc(uint) -> uint = proc(i) i;
         g
     };
-    let mut pool = TaskPool::new(4, Some(SingleThreaded), f);
+    let mut pool = TaskPool::new(4, f);
     8.times(|| {
         pool.execute(proc(i) println!("Hello from thread {}!", *i));
     })
diff --git a/src/libstd/rt/basic.rs b/src/libgreen/basic.rs
similarity index 79%
rename from src/libstd/rt/basic.rs
rename to src/libgreen/basic.rs
index 3589582357c..0574792c18d 100644
--- a/src/libstd/rt/basic.rs
+++ b/src/libgreen/basic.rs
@@ -11,15 +11,15 @@
 //! This is a basic event loop implementation not meant for any "real purposes"
 //! other than testing the scheduler and proving that it's possible to have a
 //! pluggable event loop.
+//!
+//! This implementation is also used as the fallback implementation of an event
+//! loop if no other one is provided (and M:N scheduling is desired).
 
-use prelude::*;
-
-use cast;
-use rt::rtio::{EventLoop, IoFactory, RemoteCallback, PausableIdleCallback,
-               Callback};
-use unstable::sync::Exclusive;
-use io::native;
-use util;
+use std::cast;
+use std::rt::rtio::{EventLoop, IoFactory, RemoteCallback, PausableIdleCallback,
+                    Callback};
+use std::unstable::sync::Exclusive;
+use std::util;
 
 /// This is the only exported function from this module.
 pub fn event_loop() -> ~EventLoop {
@@ -32,7 +32,6 @@ struct BasicLoop {
     remotes: ~[(uint, ~Callback)],
     next_remote: uint,
     messages: Exclusive<~[Message]>,
-    io: ~IoFactory,
 }
 
 enum Message { RunRemote(uint), RemoveRemote(uint) }
@@ -45,7 +44,6 @@ impl BasicLoop {
             next_remote: 0,
             remotes: ~[],
             messages: Exclusive::new(~[]),
-            io: ~native::IoFactory as ~IoFactory,
         }
     }
 
@@ -159,10 +157,7 @@ impl EventLoop for BasicLoop {
         ~BasicRemote::new(self.messages.clone(), id) as ~RemoteCallback
     }
 
-    fn io<'a>(&'a mut self) -> Option<&'a mut IoFactory> {
-        let factory: &mut IoFactory = self.io;
-        Some(factory)
-    }
+    fn io<'a>(&'a mut self) -> Option<&'a mut IoFactory> { None }
 }
 
 struct BasicRemote {
@@ -228,3 +223,61 @@ impl Drop for BasicPausable {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use std::task::TaskOpts;
+
+    use basic;
+    use PoolConfig;
+    use SchedPool;
+
+    fn pool() -> SchedPool {
+        SchedPool::new(PoolConfig {
+            threads: 1,
+            event_loop_factory: Some(basic::event_loop),
+        })
+    }
+
+    fn run(f: proc()) {
+        let mut pool = pool();
+        pool.spawn(TaskOpts::new(), f);
+        pool.shutdown();
+    }
+
+    #[test]
+    fn smoke() {
+        do run {}
+    }
+
+    #[test]
+    fn some_channels() {
+        do run {
+            let (p, c) = Chan::new();
+            do spawn {
+                c.send(());
+            }
+            p.recv();
+        }
+    }
+
+    #[test]
+    fn multi_thread() {
+        let mut pool = SchedPool::new(PoolConfig {
+            threads: 2,
+            event_loop_factory: Some(basic::event_loop),
+        });
+
+        for _ in range(0, 20) {
+            do pool.spawn(TaskOpts::new()) {
+                let (p, c) = Chan::new();
+                do spawn {
+                    c.send(());
+                }
+                p.recv();
+            }
+        }
+
+        pool.shutdown();
+    }
+}
diff --git a/src/libstd/rt/context.rs b/src/libgreen/context.rs
similarity index 53%
rename from src/libstd/rt/context.rs
rename to src/libgreen/context.rs
index 31cf0696881..8530e3e837e 100644
--- a/src/libstd/rt/context.rs
+++ b/src/libgreen/context.rs
@@ -8,14 +8,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use option::*;
-use super::stack::StackSegment;
-use libc::c_void;
-use uint;
-use cast::{transmute, transmute_mut_unsafe,
-           transmute_region, transmute_mut_region};
+use std::libc::c_void;
+use std::uint;
+use std::cast::{transmute, transmute_mut_unsafe,
+                transmute_region, transmute_mut_region};
+use std::unstable::stack;
 
-pub static RED_ZONE: uint = 20 * 1024;
+use stack::StackSegment;
 
 // FIXME #7761: Registers is boxed so that it is 16-byte aligned, for storing
 // SSE regs.  It would be marginally better not to do this. In C++ we
@@ -43,32 +42,47 @@ impl Context {
 
     /// Create a new context that will resume execution by running proc()
     pub fn new(start: proc(), stack: &mut StackSegment) -> Context {
-        // FIXME #7767: Putting main into a ~ so it's a thin pointer and can
-        // be passed to the spawn function.  Another unfortunate
-        // allocation
-        let start = ~start;
-
         // The C-ABI function that is the task entry point
+        //
+        // Note that this function is a little sketchy. We're taking a
+        // procedure, transmuting it to a stack-closure, and then calling to
+        // closure. This leverages the fact that the representation of these two
+        // types is the same.
+        //
+        // The reason that we're doing this is that this procedure is expected
+        // to never return. The codegen which frees the environment of the
+        // procedure occurs *after* the procedure has completed, and this means
+        // that we'll never actually free the procedure.
+        //
+        // To solve this, we use this transmute (to not trigger the procedure
+        // deallocation here), and then store a copy of the procedure in the
+        // `Context` structure returned. When the `Context` is deallocated, then
+        // the entire procedure box will be deallocated as well.
         extern fn task_start_wrapper(f: &proc()) {
-            // XXX(pcwalton): This may be sketchy.
             unsafe {
                 let f: &|| = transmute(f);
                 (*f)()
             }
         }
 
-        let fp: *c_void = task_start_wrapper as *c_void;
-        let argp: *c_void = unsafe { transmute::<&proc(), *c_void>(&*start) };
         let sp: *uint = stack.end();
         let sp: *mut uint = unsafe { transmute_mut_unsafe(sp) };
         // Save and then immediately load the current context,
         // which we will then modify to call the given function when restored
         let mut regs = new_regs();
         unsafe {
-            rust_swap_registers(transmute_mut_region(&mut *regs), transmute_region(&*regs));
+            rust_swap_registers(transmute_mut_region(&mut *regs),
+                                transmute_region(&*regs));
         };
 
-        initialize_call_frame(&mut *regs, fp, argp, sp);
+        // FIXME #7767: Putting main into a ~ so it's a thin pointer and can
+        // be passed to the spawn function.  Another unfortunate
+        // allocation
+        let start = ~start;
+        initialize_call_frame(&mut *regs,
+                              task_start_wrapper as *c_void,
+                              unsafe { transmute(&*start) },
+                              sp);
 
         // Scheduler tasks don't have a stack in the "we allocated it" sense,
         // but rather they run on pthreads stacks. We have complete control over
@@ -113,17 +127,18 @@ impl Context {
             // invalid for the current task. Lucky for us `rust_swap_registers`
             // is a C function so we don't have to worry about that!
             match in_context.stack_bounds {
-                Some((lo, hi)) => record_stack_bounds(lo, hi),
+                Some((lo, hi)) => stack::record_stack_bounds(lo, hi),
                 // If we're going back to one of the original contexts or
                 // something that's possibly not a "normal task", then reset
                 // the stack limit to 0 to make morestack never fail
-                None => record_stack_bounds(0, uint::max_value),
+                None => stack::record_stack_bounds(0, uint::max_value),
             }
             rust_swap_registers(out_regs, in_regs)
         }
     }
 }
 
+#[link(name = "rustrt", kind = "static")]
 extern {
     fn rust_swap_registers(out_regs: *mut Registers, in_regs: *Registers);
 }
@@ -282,182 +297,6 @@ fn align_down(sp: *mut uint) -> *mut uint {
 // ptr::mut_offset is positive ints only
 #[inline]
 pub fn mut_offset<T>(ptr: *mut T, count: int) -> *mut T {
-    use mem::size_of;
+    use std::mem::size_of;
     (ptr as int + count * (size_of::<T>() as int)) as *mut T
 }
-
-#[inline(always)]
-pub unsafe fn record_stack_bounds(stack_lo: uint, stack_hi: uint) {
-    // When the old runtime had segmented stacks, it used a calculation that was
-    // "limit + RED_ZONE + FUDGE". The red zone was for things like dynamic
-    // symbol resolution, llvm function calls, etc. In theory this red zone
-    // value is 0, but it matters far less when we have gigantic stacks because
-    // we don't need to be so exact about our stack budget. The "fudge factor"
-    // was because LLVM doesn't emit a stack check for functions < 256 bytes in
-    // size. Again though, we have giant stacks, so we round all these
-    // calculations up to the nice round number of 20k.
-    record_sp_limit(stack_lo + RED_ZONE);
-
-    return target_record_stack_bounds(stack_lo, stack_hi);
-
-    #[cfg(not(windows))] #[cfg(not(target_arch = "x86_64"))] #[inline(always)]
-    unsafe fn target_record_stack_bounds(_stack_lo: uint, _stack_hi: uint) {}
-    #[cfg(windows, target_arch = "x86_64")] #[inline(always)]
-    unsafe fn target_record_stack_bounds(stack_lo: uint, stack_hi: uint) {
-        // Windows compiles C functions which may check the stack bounds. This
-        // means that if we want to perform valid FFI on windows, then we need
-        // to ensure that the stack bounds are what they truly are for this
-        // task. More info can be found at:
-        //   https://github.com/mozilla/rust/issues/3445#issuecomment-26114839
-        //
-        // stack range is at TIB: %gs:0x08 (top) and %gs:0x10 (bottom)
-        asm!("mov $0, %gs:0x08" :: "r"(stack_hi) :: "volatile");
-        asm!("mov $0, %gs:0x10" :: "r"(stack_lo) :: "volatile");
-    }
-}
-
-/// Records the current limit of the stack as specified by `end`.
-///
-/// This is stored in an OS-dependent location, likely inside of the thread
-/// local storage. The location that the limit is stored is a pre-ordained
-/// location because it's where LLVM has emitted code to check.
-///
-/// Note that this cannot be called under normal circumstances. This function is
-/// changing the stack limit, so upon returning any further function calls will
-/// possibly be triggering the morestack logic if you're not careful.
-///
-/// Also note that this and all of the inside functions are all flagged as
-/// "inline(always)" because they're messing around with the stack limits.  This
-/// would be unfortunate for the functions themselves to trigger a morestack
-/// invocation (if they were an actual function call).
-#[inline(always)]
-pub unsafe fn record_sp_limit(limit: uint) {
-    return target_record_sp_limit(limit);
-
-    // x86-64
-    #[cfg(target_arch = "x86_64", target_os = "macos")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        asm!("movq $$0x60+90*8, %rsi
-              movq $0, %gs:(%rsi)" :: "r"(limit) : "rsi" : "volatile")
-    }
-    #[cfg(target_arch = "x86_64", target_os = "linux")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        asm!("movq $0, %fs:112" :: "r"(limit) :: "volatile")
-    }
-    #[cfg(target_arch = "x86_64", target_os = "win32")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        // see: http://en.wikipedia.org/wiki/Win32_Thread_Information_Block
-        // store this inside of the "arbitrary data slot", but double the size
-        // because this is 64 bit instead of 32 bit
-        asm!("movq $0, %gs:0x28" :: "r"(limit) :: "volatile")
-    }
-    #[cfg(target_arch = "x86_64", target_os = "freebsd")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        asm!("movq $0, %fs:24" :: "r"(limit) :: "volatile")
-    }
-
-    // x86
-    #[cfg(target_arch = "x86", target_os = "macos")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        asm!("movl $$0x48+90*4, %eax
-              movl $0, %gs:(%eax)" :: "r"(limit) : "eax" : "volatile")
-    }
-    #[cfg(target_arch = "x86", target_os = "linux")]
-    #[cfg(target_arch = "x86", target_os = "freebsd")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        asm!("movl $0, %gs:48" :: "r"(limit) :: "volatile")
-    }
-    #[cfg(target_arch = "x86", target_os = "win32")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        // see: http://en.wikipedia.org/wiki/Win32_Thread_Information_Block
-        // store this inside of the "arbitrary data slot"
-        asm!("movl $0, %fs:0x14" :: "r"(limit) :: "volatile")
-    }
-
-    // mips, arm - Some brave soul can port these to inline asm, but it's over
-    //             my head personally
-    #[cfg(target_arch = "mips")]
-    #[cfg(target_arch = "arm")] #[inline(always)]
-    unsafe fn target_record_sp_limit(limit: uint) {
-        return record_sp_limit(limit as *c_void);
-        extern {
-            fn record_sp_limit(limit: *c_void);
-        }
-    }
-}
-
-/// The counterpart of the function above, this function will fetch the current
-/// stack limit stored in TLS.
-///
-/// Note that all of these functions are meant to be exact counterparts of their
-/// brethren above, except that the operands are reversed.
-///
-/// As with the setter, this function does not have a __morestack header and can
-/// therefore be called in a "we're out of stack" situation.
-#[inline(always)]
-// currently only called by `rust_stack_exhausted`, which doesn't
-// exist in a test build.
-#[cfg(not(test))]
-pub unsafe fn get_sp_limit() -> uint {
-    return target_get_sp_limit();
-
-    // x86-64
-    #[cfg(target_arch = "x86_64", target_os = "macos")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movq $$0x60+90*8, %rsi
-              movq %gs:(%rsi), $0" : "=r"(limit) :: "rsi" : "volatile");
-        return limit;
-    }
-    #[cfg(target_arch = "x86_64", target_os = "linux")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movq %fs:112, $0" : "=r"(limit) ::: "volatile");
-        return limit;
-    }
-    #[cfg(target_arch = "x86_64", target_os = "win32")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movq %gs:0x28, $0" : "=r"(limit) ::: "volatile");
-        return limit;
-    }
-    #[cfg(target_arch = "x86_64", target_os = "freebsd")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movq %fs:24, $0" : "=r"(limit) ::: "volatile");
-        return limit;
-    }
-
-    // x86
-    #[cfg(target_arch = "x86", target_os = "macos")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movl $$0x48+90*4, %eax
-              movl %gs:(%eax), $0" : "=r"(limit) :: "eax" : "volatile");
-        return limit;
-    }
-    #[cfg(target_arch = "x86", target_os = "linux")]
-    #[cfg(target_arch = "x86", target_os = "freebsd")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movl %gs:48, $0" : "=r"(limit) ::: "volatile");
-        return limit;
-    }
-    #[cfg(target_arch = "x86", target_os = "win32")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        let limit;
-        asm!("movl %fs:0x14, $0" : "=r"(limit) ::: "volatile");
-        return limit;
-    }
-
-    // mips, arm - Some brave soul can port these to inline asm, but it's over
-    //             my head personally
-    #[cfg(target_arch = "mips")]
-    #[cfg(target_arch = "arm")] #[inline(always)]
-    unsafe fn target_get_sp_limit() -> uint {
-        return get_sp_limit() as uint;
-        extern {
-            fn get_sp_limit() -> *c_void;
-        }
-    }
-}
diff --git a/src/libgreen/coroutine.rs b/src/libgreen/coroutine.rs
new file mode 100644
index 00000000000..7bc5d0accfe
--- /dev/null
+++ b/src/libgreen/coroutine.rs
@@ -0,0 +1,62 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Coroutines represent nothing more than a context and a stack
+// segment.
+
+use std::rt::env;
+
+use context::Context;
+use stack::{StackPool, StackSegment};
+
+/// A coroutine is nothing more than a (register context, stack) pair.
+pub struct Coroutine {
+    /// The segment of stack on which the task is currently running or
+    /// if the task is blocked, on which the task will resume
+    /// execution.
+    ///
+    /// Servo needs this to be public in order to tell SpiderMonkey
+    /// about the stack bounds.
+    current_stack_segment: StackSegment,
+
+    /// Always valid if the task is alive and not running.
+    saved_context: Context
+}
+
+impl Coroutine {
+    pub fn new(stack_pool: &mut StackPool,
+               stack_size: Option<uint>,
+               start: proc())
+               -> Coroutine {
+        let stack_size = match stack_size {
+            Some(size) => size,
+            None => env::min_stack()
+        };
+        let mut stack = stack_pool.take_segment(stack_size);
+        let initial_context = Context::new(start, &mut stack);
+        Coroutine {
+            current_stack_segment: stack,
+            saved_context: initial_context
+        }
+    }
+
+    pub fn empty() -> Coroutine {
+        Coroutine {
+            current_stack_segment: StackSegment::new(0),
+            saved_context: Context::empty()
+        }
+    }
+
+    /// Destroy coroutine and try to reuse std::stack segment.
+    pub fn recycle(self, stack_pool: &mut StackPool) {
+        let Coroutine { current_stack_segment, .. } = self;
+        stack_pool.give_segment(current_stack_segment);
+    }
+}
diff --git a/src/libgreen/lib.rs b/src/libgreen/lib.rs
new file mode 100644
index 00000000000..3a2e8a2b36c
--- /dev/null
+++ b/src/libgreen/lib.rs
@@ -0,0 +1,320 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The "green scheduling" library
+//!
+//! This library provides M:N threading for rust programs. Internally this has
+//! the implementation of a green scheduler along with context switching and a
+//! stack-allocation strategy.
+//!
+//! This can be optionally linked in to rust programs in order to provide M:N
+//! functionality inside of 1:1 programs.
+
+#[pkgid = "green#0.9-pre"];
+#[crate_id = "green#0.9-pre"];
+#[license = "MIT/ASL2"];
+#[crate_type = "rlib"];
+#[crate_type = "dylib"];
+
+// NB this does *not* include globs, please keep it that way.
+#[feature(macro_rules)];
+
+use std::os;
+use std::rt::crate_map;
+use std::rt::local::Local;
+use std::rt::rtio;
+use std::rt::task::Task;
+use std::rt::thread::Thread;
+use std::rt;
+use std::sync::atomics::{SeqCst, AtomicUint, INIT_ATOMIC_UINT};
+use std::sync::deque;
+use std::task::TaskOpts;
+use std::util;
+use std::vec;
+
+use sched::{Shutdown, Scheduler, SchedHandle, TaskFromFriend, NewNeighbor};
+use sleeper_list::SleeperList;
+use stack::StackPool;
+use task::GreenTask;
+
+mod macros;
+mod simple;
+
+pub mod basic;
+pub mod context;
+pub mod coroutine;
+pub mod sched;
+pub mod sleeper_list;
+pub mod stack;
+pub mod task;
+
+#[lang = "start"]
+#[cfg(not(test))]
+pub fn lang_start(main: *u8, argc: int, argv: **u8) -> int {
+    use std::cast;
+    do start(argc, argv) {
+        let main: extern "Rust" fn() = unsafe { cast::transmute(main) };
+        main();
+    }
+}
+
+/// Set up a default runtime configuration, given compiler-supplied arguments.
+///
+/// This function will block until the entire pool of M:N schedulers have
+/// exited. This function also requires a local task to be available.
+///
+/// # Arguments
+///
+/// * `argc` & `argv` - The argument vector. On Unix this information is used
+///   by os::args.
+/// * `main` - The initial procedure to run inside of the M:N scheduling pool.
+///            Once this procedure exits, the scheduling pool will begin to shut
+///            down. The entire pool (and this function) will only return once
+///            all child tasks have finished executing.
+///
+/// # Return value
+///
+/// The return value is used as the process return code. 0 on success, 101 on
+/// error.
+pub fn start(argc: int, argv: **u8, main: proc()) -> int {
+    rt::init(argc, argv);
+    let mut main = Some(main);
+    let mut ret = None;
+    simple::task().run(|| {
+        ret = Some(run(main.take_unwrap()));
+    });
+    // unsafe is ok b/c we're sure that the runtime is gone
+    unsafe { rt::cleanup() }
+    ret.unwrap()
+}
+
+/// Execute the main function in a pool of M:N schedulers.
+///
+/// Configures the runtime according to the environment, by default using a task
+/// scheduler with the same number of threads as cores.  Returns a process exit
+/// code.
+///
+/// This function will not return until all schedulers in the associated pool
+/// have returned.
+pub fn run(main: proc()) -> int {
+    // Create a scheduler pool and spawn the main task into this pool. We will
+    // get notified over a channel when the main task exits.
+    let mut pool = SchedPool::new(PoolConfig::new());
+    let (port, chan) = Chan::new();
+    let mut opts = TaskOpts::new();
+    opts.notify_chan = Some(chan);
+    opts.name = Some(SendStrStatic("<main>"));
+    pool.spawn(opts, main);
+
+    // Wait for the main task to return, and set the process error code
+    // appropriately.
+    if port.recv().is_err() {
+        os::set_exit_status(rt::DEFAULT_ERROR_CODE);
+    }
+
+    // Once the main task has exited and we've set our exit code, wait for all
+    // spawned sub-tasks to finish running. This is done to allow all schedulers
+    // to remain active while there are still tasks possibly running.
+    unsafe {
+        let mut task = Local::borrow(None::<Task>);
+        task.get().wait_for_other_tasks();
+    }
+
+    // Now that we're sure all tasks are dead, shut down the pool of schedulers,
+    // waiting for them all to return.
+    pool.shutdown();
+    os::get_exit_status()
+}
+
+/// Configuration of how an M:N pool of schedulers is spawned.
+pub struct PoolConfig {
+    /// The number of schedulers (OS threads) to spawn into this M:N pool.
+    threads: uint,
+    /// A factory function used to create new event loops. If this is not
+    /// specified then the default event loop factory is used.
+    event_loop_factory: Option<fn() -> ~rtio::EventLoop>,
+}
+
+impl PoolConfig {
+    /// Returns the default configuration, as determined the the environment
+    /// variables of this process.
+    pub fn new() -> PoolConfig {
+        PoolConfig {
+            threads: rt::default_sched_threads(),
+            event_loop_factory: None,
+        }
+    }
+}
+
+/// A structure representing a handle to a pool of schedulers. This handle is
+/// used to keep the pool alive and also reap the status from the pool.
+pub struct SchedPool {
+    priv id: uint,
+    priv threads: ~[Thread<()>],
+    priv handles: ~[SchedHandle],
+    priv stealers: ~[deque::Stealer<~task::GreenTask>],
+    priv next_friend: uint,
+    priv stack_pool: StackPool,
+    priv deque_pool: deque::BufferPool<~task::GreenTask>,
+    priv sleepers: SleeperList,
+    priv factory: fn() -> ~rtio::EventLoop,
+}
+
+impl SchedPool {
+    /// Execute the main function in a pool of M:N schedulers.
+    ///
+    /// This will configure the pool according to the `config` parameter, and
+    /// initially run `main` inside the pool of schedulers.
+    pub fn new(config: PoolConfig) -> SchedPool {
+        static mut POOL_ID: AtomicUint = INIT_ATOMIC_UINT;
+
+        let PoolConfig {
+            threads: nscheds,
+            event_loop_factory: factory
+        } = config;
+        let factory = factory.unwrap_or(default_event_loop_factory());
+        assert!(nscheds > 0);
+
+        // The pool of schedulers that will be returned from this function
+        let mut pool = SchedPool {
+            threads: ~[],
+            handles: ~[],
+            stealers: ~[],
+            id: unsafe { POOL_ID.fetch_add(1, SeqCst) },
+            sleepers: SleeperList::new(),
+            stack_pool: StackPool::new(),
+            deque_pool: deque::BufferPool::new(),
+            next_friend: 0,
+            factory: factory,
+        };
+
+        // Create a work queue for each scheduler, ntimes. Create an extra
+        // for the main thread if that flag is set. We won't steal from it.
+        let arr = vec::from_fn(nscheds, |_| pool.deque_pool.deque());
+        let (workers, stealers) = vec::unzip(arr.move_iter());
+        pool.stealers = stealers;
+
+        // Now that we've got all our work queues, create one scheduler per
+        // queue, spawn the scheduler into a thread, and be sure to keep a
+        // handle to the scheduler and the thread to keep them alive.
+        for worker in workers.move_iter() {
+            rtdebug!("inserting a regular scheduler");
+
+            let mut sched = ~Scheduler::new(pool.id,
+                                            (pool.factory)(),
+                                            worker,
+                                            pool.stealers.clone(),
+                                            pool.sleepers.clone());
+            pool.handles.push(sched.make_handle());
+            let sched = sched;
+            pool.threads.push(do Thread::start {
+                let mut sched = sched;
+                let task = do GreenTask::new(&mut sched.stack_pool, None) {
+                    rtdebug!("boostraping a non-primary scheduler");
+                };
+                sched.bootstrap(task);
+            });
+        }
+
+        return pool;
+    }
+
+    pub fn task(&mut self, opts: TaskOpts, f: proc()) -> ~GreenTask {
+        GreenTask::configure(&mut self.stack_pool, opts, f)
+    }
+
+    pub fn spawn(&mut self, opts: TaskOpts, f: proc()) {
+        let task = self.task(opts, f);
+
+        // Figure out someone to send this task to
+        let idx = self.next_friend;
+        self.next_friend += 1;
+        if self.next_friend >= self.handles.len() {
+            self.next_friend = 0;
+        }
+
+        // Jettison the task away!
+        self.handles[idx].send(TaskFromFriend(task));
+    }
+
+    /// Spawns a new scheduler into this M:N pool. A handle is returned to the
+    /// scheduler for use. The scheduler will not exit as long as this handle is
+    /// active.
+    ///
+    /// The scheduler spawned will participate in work stealing with all of the
+    /// other schedulers currently in the scheduler pool.
+    pub fn spawn_sched(&mut self) -> SchedHandle {
+        let (worker, stealer) = self.deque_pool.deque();
+        self.stealers.push(stealer.clone());
+
+        // Tell all existing schedulers about this new scheduler so they can all
+        // steal work from it
+        for handle in self.handles.mut_iter() {
+            handle.send(NewNeighbor(stealer.clone()));
+        }
+
+        // Create the new scheduler, using the same sleeper list as all the
+        // other schedulers as well as having a stealer handle to all other
+        // schedulers.
+        let mut sched = ~Scheduler::new(self.id,
+                                        (self.factory)(),
+                                        worker,
+                                        self.stealers.clone(),
+                                        self.sleepers.clone());
+        let ret = sched.make_handle();
+        self.handles.push(sched.make_handle());
+        let sched = sched;
+        self.threads.push(do Thread::start {
+            let mut sched = sched;
+            let task = do GreenTask::new(&mut sched.stack_pool, None) {
+                rtdebug!("boostraping a non-primary scheduler");
+            };
+            sched.bootstrap(task);
+        });
+
+        return ret;
+    }
+
+    pub fn shutdown(mut self) {
+        self.stealers = ~[];
+
+        for mut handle in util::replace(&mut self.handles, ~[]).move_iter() {
+            handle.send(Shutdown);
+        }
+        for thread in util::replace(&mut self.threads, ~[]).move_iter() {
+            thread.join();
+        }
+    }
+}
+
+impl Drop for SchedPool {
+    fn drop(&mut self) {
+        if self.threads.len() > 0 {
+            fail!("dropping a M:N scheduler pool that wasn't shut down");
+        }
+    }
+}
+
+fn default_event_loop_factory() -> fn() -> ~rtio::EventLoop {
+    match crate_map::get_crate_map() {
+        None => {}
+        Some(map) => {
+            match map.event_loop_factory {
+                None => {}
+                Some(factory) => return factory
+            }
+        }
+    }
+
+    // If the crate map didn't specify a factory to create an event loop, then
+    // instead just use a basic event loop missing all I/O services to at least
+    // get the scheduler running.
+    return basic::event_loop;
+}
diff --git a/src/libgreen/macros.rs b/src/libgreen/macros.rs
new file mode 100644
index 00000000000..56dc3204da8
--- /dev/null
+++ b/src/libgreen/macros.rs
@@ -0,0 +1,129 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// XXX: this file probably shouldn't exist
+
+#[macro_escape];
+
+use std::fmt;
+use std::libc;
+
+// Indicates whether we should perform expensive sanity checks, including rtassert!
+// XXX: Once the runtime matures remove the `true` below to turn off rtassert, etc.
+pub static ENFORCE_SANITY: bool = true || !cfg!(rtopt) || cfg!(rtdebug) || cfg!(rtassert);
+
+macro_rules! rterrln (
+    ($($arg:tt)*) => ( {
+        format_args!(::macros::dumb_println, $($arg)*)
+    } )
+)
+
+// Some basic logging. Enabled by passing `--cfg rtdebug` to the libstd build.
+macro_rules! rtdebug (
+    ($($arg:tt)*) => ( {
+        if cfg!(rtdebug) {
+            rterrln!($($arg)*)
+        }
+    })
+)
+
+macro_rules! rtassert (
+    ( $arg:expr ) => ( {
+        if ::macros::ENFORCE_SANITY {
+            if !$arg {
+                rtabort!(" assertion failed: {}", stringify!($arg));
+            }
+        }
+    } )
+)
+
+
+macro_rules! rtabort (
+    ($($arg:tt)*) => ( {
+        ::macros::abort(format!($($arg)*));
+    } )
+)
+
+pub fn dumb_println(args: &fmt::Arguments) {
+    use std::io;
+    use std::libc;
+
+    struct Stderr;
+    impl io::Writer for Stderr {
+        fn write(&mut self, data: &[u8]) {
+            unsafe {
+                libc::write(libc::STDERR_FILENO,
+                            data.as_ptr() as *libc::c_void,
+                            data.len() as libc::size_t);
+            }
+        }
+    }
+    let mut w = Stderr;
+    fmt::writeln(&mut w as &mut io::Writer, args);
+}
+
+pub fn abort(msg: &str) -> ! {
+    let msg = if !msg.is_empty() { msg } else { "aborted" };
+    let hash = msg.chars().fold(0, |accum, val| accum + (val as uint) );
+    let quote = match hash % 10 {
+        0 => "
+It was from the artists and poets that the pertinent answers came, and I
+know that panic would have broken loose had they been able to compare notes.
+As it was, lacking their original letters, I half suspected the compiler of
+having asked leading questions, or of having edited the correspondence in
+corroboration of what he had latently resolved to see.",
+        1 => "
+There are not many persons who know what wonders are opened to them in the
+stories and visions of their youth; for when as children we listen and dream,
+we think but half-formed thoughts, and when as men we try to remember, we are
+dulled and prosaic with the poison of life. But some of us awake in the night
+with strange phantasms of enchanted hills and gardens, of fountains that sing
+in the sun, of golden cliffs overhanging murmuring seas, of plains that stretch
+down to sleeping cities of bronze and stone, and of shadowy companies of heroes
+that ride caparisoned white horses along the edges of thick forests; and then
+we know that we have looked back through the ivory gates into that world of
+wonder which was ours before we were wise and unhappy.",
+        2 => "
+Instead of the poems I had hoped for, there came only a shuddering blackness
+and ineffable loneliness; and I saw at last a fearful truth which no one had
+ever dared to breathe before — the unwhisperable secret of secrets — The fact
+that this city of stone and stridor is not a sentient perpetuation of Old New
+York as London is of Old London and Paris of Old Paris, but that it is in fact
+quite dead, its sprawling body imperfectly embalmed and infested with queer
+animate things which have nothing to do with it as it was in life.",
+        3 => "
+The ocean ate the last of the land and poured into the smoking gulf, thereby
+giving up all it had ever conquered. From the new-flooded lands it flowed
+again, uncovering death and decay; and from its ancient and immemorial bed it
+trickled loathsomely, uncovering nighted secrets of the years when Time was
+young and the gods unborn. Above the waves rose weedy remembered spires. The
+moon laid pale lilies of light on dead London, and Paris stood up from its damp
+grave to be sanctified with star-dust. Then rose spires and monoliths that were
+weedy but not remembered; terrible spires and monoliths of lands that men never
+knew were lands...",
+        4 => "
+There was a night when winds from unknown spaces whirled us irresistibly into
+limitless vacuum beyond all thought and entity. Perceptions of the most
+maddeningly untransmissible sort thronged upon us; perceptions of infinity
+which at the time convulsed us with joy, yet which are now partly lost to my
+memory and partly incapable of presentation to others.",
+        _ => "You've met with a terrible fate, haven't you?"
+    };
+    rterrln!("{}", "");
+    rterrln!("{}", quote);
+    rterrln!("{}", "");
+    rterrln!("fatal runtime error: {}", msg);
+
+    abort();
+
+    fn abort() -> ! {
+        unsafe { libc::abort() }
+    }
+}
diff --git a/src/libstd/rt/sched.rs b/src/libgreen/sched.rs
similarity index 61%
rename from src/libstd/rt/sched.rs
rename to src/libgreen/sched.rs
index 15aa1602cd0..ef62f654ddf 100644
--- a/src/libstd/rt/sched.rs
+++ b/src/libgreen/sched.rs
@@ -8,27 +8,22 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use option::{Option, Some, None};
-use cast::{transmute, transmute_mut_region, transmute_mut_unsafe};
-use clone::Clone;
-use unstable::raw;
-use super::sleeper_list::SleeperList;
-use super::stack::{StackPool};
-use super::rtio::EventLoop;
-use super::context::Context;
-use super::task::{Task, AnySched, Sched};
-use rt::kill::BlockedTask;
-use rt::deque;
-use rt::local_ptr;
-use rt::local::Local;
-use rt::rtio::{RemoteCallback, PausableIdleCallback, Callback};
-use borrow::{to_uint};
-use rand::{XorShiftRng, Rng, Rand};
-use iter::range;
-use unstable::mutex::Mutex;
-use vec::{OwnedVector};
+use std::cast;
+use std::rand::{XorShiftRng, Rng, Rand};
+use std::rt::local::Local;
+use std::rt::rtio::{RemoteCallback, PausableIdleCallback, Callback, EventLoop};
+use std::rt::task::BlockedTask;
+use std::rt::task::Task;
+use std::sync::deque;
+use std::unstable::mutex::Mutex;
+use std::unstable::raw;
+use mpsc = std::sync::mpsc_queue;
 
-use mpsc = super::mpsc_queue;
+use context::Context;
+use coroutine::Coroutine;
+use sleeper_list::SleeperList;
+use stack::StackPool;
+use task::{TypeSched, GreenTask, HomeSched, AnySched};
 
 /// A scheduler is responsible for coordinating the execution of Tasks
 /// on a single thread. The scheduler runs inside a slightly modified
@@ -39,11 +34,15 @@ use mpsc = super::mpsc_queue;
 /// XXX: This creates too many callbacks to run_sched_once, resulting
 /// in too much allocation and too many events.
 pub struct Scheduler {
+    /// ID number of the pool that this scheduler is a member of. When
+    /// reawakening green tasks, this is used to ensure that tasks aren't
+    /// reawoken on the wrong pool of schedulers.
+    pool_id: uint,
     /// There are N work queues, one per scheduler.
-    work_queue: deque::Worker<~Task>,
+    work_queue: deque::Worker<~GreenTask>,
     /// Work queues for the other schedulers. These are created by
     /// cloning the core work queues.
-    work_queues: ~[deque::Stealer<~Task>],
+    work_queues: ~[deque::Stealer<~GreenTask>],
     /// The queue of incoming messages from other schedulers.
     /// These are enqueued by SchedHandles after which a remote callback
     /// is triggered to handle the message.
@@ -66,15 +65,15 @@ pub struct Scheduler {
     stack_pool: StackPool,
     /// The scheduler runs on a special task. When it is not running
     /// it is stored here instead of the work queue.
-    sched_task: Option<~Task>,
+    sched_task: Option<~GreenTask>,
     /// An action performed after a context switch on behalf of the
     /// code running before the context switch
     cleanup_job: Option<CleanupJob>,
-    /// Should this scheduler run any task, or only pinned tasks?
-    run_anything: bool,
     /// If the scheduler shouldn't run some tasks, a friend to send
     /// them to.
     friend_handle: Option<SchedHandle>,
+    /// Should this scheduler run any task, or only pinned tasks?
+    run_anything: bool,
     /// A fast XorShift rng for scheduler use
     rng: XorShiftRng,
     /// A togglable idle callback
@@ -117,21 +116,22 @@ impl Scheduler {
 
     // * Initialization Functions
 
-    pub fn new(event_loop: ~EventLoop,
-               work_queue: deque::Worker<~Task>,
-               work_queues: ~[deque::Stealer<~Task>],
+    pub fn new(pool_id: uint,
+               event_loop: ~EventLoop,
+               work_queue: deque::Worker<~GreenTask>,
+               work_queues: ~[deque::Stealer<~GreenTask>],
                sleeper_list: SleeperList)
         -> Scheduler {
 
-        Scheduler::new_special(event_loop, work_queue,
-                               work_queues,
+        Scheduler::new_special(pool_id, event_loop, work_queue, work_queues,
                                sleeper_list, true, None)
 
     }
 
-    pub fn new_special(event_loop: ~EventLoop,
-                       work_queue: deque::Worker<~Task>,
-                       work_queues: ~[deque::Stealer<~Task>],
+    pub fn new_special(pool_id: uint,
+                       event_loop: ~EventLoop,
+                       work_queue: deque::Worker<~GreenTask>,
+                       work_queues: ~[deque::Stealer<~GreenTask>],
                        sleeper_list: SleeperList,
                        run_anything: bool,
                        friend: Option<SchedHandle>)
@@ -139,6 +139,7 @@ impl Scheduler {
 
         let (consumer, producer) = mpsc::queue(());
         let mut sched = Scheduler {
+            pool_id: pool_id,
             sleeper_list: sleeper_list,
             message_queue: consumer,
             message_producer: producer,
@@ -170,66 +171,58 @@ impl Scheduler {
 
     // Take a main task to run, and a scheduler to run it in. Create a
     // scheduler task and bootstrap into it.
-    pub fn bootstrap(mut ~self, task: ~Task) {
+    pub fn bootstrap(mut ~self, task: ~GreenTask) {
 
         // Build an Idle callback.
         let cb = ~SchedRunner as ~Callback;
         self.idle_callback = Some(self.event_loop.pausable_idle_callback(cb));
 
-        // Initialize the TLS key.
-        local_ptr::init();
-
         // Create a task for the scheduler with an empty context.
-        let sched_task = ~Task::new_sched_task();
-
-        // Now that we have an empty task struct for the scheduler
-        // task, put it in TLS.
-        Local::put(sched_task);
+        let sched_task = GreenTask::new_typed(Some(Coroutine::empty()),
+                                              TypeSched);
 
         // Before starting our first task, make sure the idle callback
         // is active. As we do not start in the sleep state this is
         // important.
         self.idle_callback.get_mut_ref().resume();
 
-        // Now, as far as all the scheduler state is concerned, we are
-        // inside the "scheduler" context. So we can act like the
-        // scheduler and resume the provided task.
-        self.resume_task_immediately(task);
+        // Now, as far as all the scheduler state is concerned, we are inside
+        // the "scheduler" context. So we can act like the scheduler and resume
+        // the provided task. Let it think that the currently running task is
+        // actually the sched_task so it knows where to squirrel it away.
+        let mut sched_task = self.resume_task_immediately(sched_task, task);
 
         // Now we are back in the scheduler context, having
         // successfully run the input task. Start by running the
         // scheduler. Grab it out of TLS - performing the scheduler
         // action will have given it away.
-        let sched: ~Scheduler = Local::take();
-
+        let sched = sched_task.sched.take_unwrap();
         rtdebug!("starting scheduler {}", sched.sched_id());
-        sched.run();
+        let mut sched_task = sched.run(sched_task);
 
         // Close the idle callback.
-        let mut sched: ~Scheduler = Local::take();
+        let mut sched = sched_task.sched.take_unwrap();
         sched.idle_callback.take();
         // Make one go through the loop to run the close callback.
-        sched.run();
+        let mut stask = sched.run(sched_task);
 
         // Now that we are done with the scheduler, clean up the
         // scheduler task. Do so by removing it from TLS and manually
         // cleaning up the memory it uses. As we didn't actually call
         // task.run() on the scheduler task we never get through all
         // the cleanup code it runs.
-        let mut stask: ~Task = Local::take();
-
         rtdebug!("stopping scheduler {}", stask.sched.get_ref().sched_id());
 
         // Should not have any messages
         let message = stask.sched.get_mut_ref().message_queue.pop();
         rtassert!(match message { mpsc::Empty => true, _ => false });
 
-        stask.destroyed = true;
+        stask.task.get_mut_ref().destroyed = true;
     }
 
     // This does not return a scheduler, as the scheduler is placed
     // inside the task.
-    pub fn run(mut ~self) {
+    pub fn run(mut ~self, stask: ~GreenTask) -> ~GreenTask {
 
         // This is unsafe because we need to place the scheduler, with
         // the event_loop inside, inside our task. But we still need a
@@ -237,16 +230,24 @@ impl Scheduler {
         // command.
         unsafe {
             let event_loop: *mut ~EventLoop = &mut self.event_loop;
-
-            {
-                // Our scheduler must be in the task before the event loop
-                // is started.
-                let mut stask = Local::borrow(None::<Task>);
-                stask.get().sched = Some(self);
-            }
-
+            // Our scheduler must be in the task before the event loop
+            // is started.
+            stask.put_with_sched(self);
             (*event_loop).run();
         }
+
+        //  This is a serious code smell, but this function could be done away
+        //  with if necessary. The ownership of `stask` was transferred into
+        //  local storage just before the event loop ran, so it is possible to
+        //  transmute `stask` as a uint across the running of the event loop to
+        //  re-acquire ownership here.
+        //
+        // This would involve removing the Task from TLS, removing the runtime,
+        // forgetting the runtime, and then putting the task into `stask`. For
+        // now, because we have `GreenTask::convert`, I chose to take this
+        // method for cleanliness. This function is *not* a fundamental reason
+        // why this function should exist.
+        GreenTask::convert(Local::take())
     }
 
     // * Execution Functions - Core Loop Logic
@@ -257,38 +258,37 @@ impl Scheduler {
     // you reach the end and sleep. In the case that a scheduler
     // action is performed the loop is evented such that this function
     // is called again.
-    fn run_sched_once() {
-
-        // When we reach the scheduler context via the event loop we
-        // already have a scheduler stored in our local task, so we
-        // start off by taking it. This is the only path through the
-        // scheduler where we get the scheduler this way.
-        let mut sched: ~Scheduler = Local::take();
+    fn run_sched_once(mut ~self, stask: ~GreenTask) {
+        // Make sure that we're not lying in that the `stask` argument is indeed
+        // the scheduler task for this scheduler.
+        assert!(self.sched_task.is_none());
 
         // Assume that we need to continue idling unless we reach the
         // end of this function without performing an action.
-        sched.idle_callback.get_mut_ref().resume();
+        self.idle_callback.get_mut_ref().resume();
 
         // First we check for scheduler messages, these are higher
         // priority than regular tasks.
-        let sched = match sched.interpret_message_queue(DontTryTooHard) {
-            Some(sched) => sched,
-            None => return
-        };
+        let (sched, stask) =
+            match self.interpret_message_queue(stask, DontTryTooHard) {
+                Some(pair) => pair,
+                None => return
+            };
 
         // This helper will use a randomized work-stealing algorithm
         // to find work.
-        let sched = match sched.do_work() {
-            Some(sched) => sched,
+        let (sched, stask) = match sched.do_work(stask) {
+            Some(pair) => pair,
             None => return
         };
 
         // Now, before sleeping we need to find out if there really
         // were any messages. Give it your best!
-        let mut sched = match sched.interpret_message_queue(GiveItYourBest) {
-            Some(sched) => sched,
-            None => return
-        };
+        let (mut sched, stask) =
+            match sched.interpret_message_queue(stask, GiveItYourBest) {
+                Some(pair) => pair,
+                None => return
+            };
 
         // If we got here then there was no work to do.
         // Generate a SchedHandle and push it to the sleeper list so
@@ -309,14 +309,17 @@ impl Scheduler {
 
         // Finished a cycle without using the Scheduler. Place it back
         // in TLS.
-        Local::put(sched);
+        stask.put_with_sched(sched);
     }
 
     // This function returns None if the scheduler is "used", or it
     // returns the still-available scheduler. At this point all
     // message-handling will count as a turn of work, and as a result
     // return None.
-    fn interpret_message_queue(mut ~self, effort: EffortLevel) -> Option<~Scheduler> {
+    fn interpret_message_queue(mut ~self, stask: ~GreenTask,
+                               effort: EffortLevel)
+        -> Option<(~Scheduler, ~GreenTask)>
+    {
 
         let msg = if effort == DontTryTooHard {
             self.message_queue.casual_pop()
@@ -345,24 +348,25 @@ impl Scheduler {
         match msg {
             Some(PinnedTask(task)) => {
                 let mut task = task;
-                task.give_home(Sched(self.make_handle()));
-                self.resume_task_immediately(task);
+                task.give_home(HomeSched(self.make_handle()));
+                self.resume_task_immediately(stask, task).put();
                 return None;
             }
             Some(TaskFromFriend(task)) => {
                 rtdebug!("got a task from a friend. lovely!");
-                self.process_task(task, Scheduler::resume_task_immediately_cl);
+                self.process_task(stask, task,
+                                  Scheduler::resume_task_immediately_cl);
                 return None;
             }
             Some(RunOnce(task)) => {
                 // bypass the process_task logic to force running this task once
                 // on this home scheduler. This is often used for I/O (homing).
-                Scheduler::resume_task_immediately_cl(self, task);
+                self.resume_task_immediately(stask, task).put();
                 return None;
             }
             Some(Wake) => {
                 self.sleepy = false;
-                Local::put(self);
+                stask.put_with_sched(self);
                 return None;
             }
             Some(Shutdown) => {
@@ -385,26 +389,31 @@ impl Scheduler {
                 // event loop references we will shut down.
                 self.no_sleep = true;
                 self.sleepy = false;
-                Local::put(self);
+                stask.put_with_sched(self);
                 return None;
             }
+            Some(NewNeighbor(neighbor)) => {
+                self.work_queues.push(neighbor);
+                return Some((self, stask));
+            }
             None => {
-                return Some(self);
+                return Some((self, stask));
             }
         }
     }
 
-    fn do_work(mut ~self) -> Option<~Scheduler> {
+    fn do_work(mut ~self, stask: ~GreenTask) -> Option<(~Scheduler, ~GreenTask)> {
         rtdebug!("scheduler calling do work");
         match self.find_work() {
             Some(task) => {
-                rtdebug!("found some work! processing the task");
-                self.process_task(task, Scheduler::resume_task_immediately_cl);
+                rtdebug!("found some work! running the task");
+                self.process_task(stask, task,
+                                  Scheduler::resume_task_immediately_cl);
                 return None;
             }
             None => {
                 rtdebug!("no work was found, returning the scheduler struct");
-                return Some(self);
+                return Some((self, stask));
             }
         }
     }
@@ -418,7 +427,7 @@ impl Scheduler {
     // First step in the process is to find a task. This function does
     // that by first checking the local queue, and if there is no work
     // there, trying to steal from the remote work queues.
-    fn find_work(&mut self) -> Option<~Task> {
+    fn find_work(&mut self) -> Option<~GreenTask> {
         rtdebug!("scheduler looking for work");
         if !self.steal_for_yield {
             match self.work_queue.pop() {
@@ -456,7 +465,7 @@ impl Scheduler {
     // Try stealing from all queues the scheduler knows about. This
     // naive implementation can steal from our own queue or from other
     // special schedulers.
-    fn try_steals(&mut self) -> Option<~Task> {
+    fn try_steals(&mut self) -> Option<~GreenTask> {
         let work_queues = &mut self.work_queues;
         let len = work_queues.len();
         let start_index = self.rng.gen_range(0, len);
@@ -476,53 +485,48 @@ impl Scheduler {
     // * Task Routing Functions - Make sure tasks send up in the right
     // place.
 
-    fn process_task(mut ~self, mut task: ~Task, schedule_fn: SchedulingFn) {
+    fn process_task(mut ~self, cur: ~GreenTask,
+                    mut next: ~GreenTask, schedule_fn: SchedulingFn) {
         rtdebug!("processing a task");
 
-        let home = task.take_unwrap_home();
-        match home {
-            Sched(home_handle) => {
+        match next.take_unwrap_home() {
+            HomeSched(home_handle) => {
                 if home_handle.sched_id != self.sched_id() {
                     rtdebug!("sending task home");
-                    task.give_home(Sched(home_handle));
-                    Scheduler::send_task_home(task);
-                    Local::put(self);
+                    next.give_home(HomeSched(home_handle));
+                    Scheduler::send_task_home(next);
+                    cur.put_with_sched(self);
                 } else {
                     rtdebug!("running task here");
-                    task.give_home(Sched(home_handle));
-                    schedule_fn(self, task);
+                    next.give_home(HomeSched(home_handle));
+                    schedule_fn(self, cur, next);
                 }
             }
             AnySched if self.run_anything => {
                 rtdebug!("running anysched task here");
-                task.give_home(AnySched);
-                schedule_fn(self, task);
+                next.give_home(AnySched);
+                schedule_fn(self, cur, next);
             }
             AnySched => {
                 rtdebug!("sending task to friend");
-                task.give_home(AnySched);
-                self.send_to_friend(task);
-                Local::put(self);
+                next.give_home(AnySched);
+                self.send_to_friend(next);
+                cur.put_with_sched(self);
             }
         }
     }
 
-    fn send_task_home(task: ~Task) {
+    fn send_task_home(task: ~GreenTask) {
         let mut task = task;
-        let mut home = task.take_unwrap_home();
-        match home {
-            Sched(ref mut home_handle) => {
-                home_handle.send(PinnedTask(task));
-            }
-            AnySched => {
-                        rtabort!("error: cannot send anysched task home");
-            }
+        match task.take_unwrap_home() {
+            HomeSched(mut home_handle) => home_handle.send(PinnedTask(task)),
+            AnySched => rtabort!("error: cannot send anysched task home"),
         }
     }
 
     /// Take a non-homed task we aren't allowed to run here and send
     /// it to the designated friend scheduler to execute.
-    fn send_to_friend(&mut self, task: ~Task) {
+    fn send_to_friend(&mut self, task: ~GreenTask) {
         rtdebug!("sending a task to friend");
         match self.friend_handle {
             Some(ref mut handle) => {
@@ -539,9 +543,10 @@ impl Scheduler {
     /// Pushes the task onto the work stealing queue and tells the
     /// event loop to run it later. Always use this instead of pushing
     /// to the work queue directly.
-    pub fn enqueue_task(&mut self, task: ~Task) {
+    pub fn enqueue_task(&mut self, task: ~GreenTask) {
 
         // We push the task onto our local queue clone.
+        assert!(!task.is_sched());
         self.work_queue.push(task);
         self.idle_callback.get_mut_ref().resume();
 
@@ -557,47 +562,31 @@ impl Scheduler {
         };
     }
 
-    /// As enqueue_task, but with the possibility for the blocked task to
-    /// already have been killed.
-    pub fn enqueue_blocked_task(&mut self, blocked_task: BlockedTask) {
-        blocked_task.wake().map(|task| self.enqueue_task(task));
-    }
-
     // * Core Context Switching Functions
 
     // The primary function for changing contexts. In the current
     // design the scheduler is just a slightly modified GreenTask, so
-    // all context swaps are from Task to Task. The only difference
+    // all context swaps are from GreenTask to GreenTask. The only difference
     // between the various cases is where the inputs come from, and
     // what is done with the resulting task. That is specified by the
     // cleanup function f, which takes the scheduler and the
     // old task as inputs.
 
     pub fn change_task_context(mut ~self,
-                               next_task: ~Task,
-                               f: |&mut Scheduler, ~Task|) {
-        // The current task is grabbed from TLS, not taken as an input.
-        // Doing an unsafe_take to avoid writing back a null pointer -
-        // We're going to call `put` later to do that.
-        let current_task: ~Task = unsafe { Local::unsafe_take() };
+                               current_task: ~GreenTask,
+                               mut next_task: ~GreenTask,
+                               f: |&mut Scheduler, ~GreenTask|) -> ~GreenTask {
+        let f_opaque = ClosureConverter::from_fn(f);
 
-        // Check that the task is not in an atomically() section (e.g.,
-        // holding a pthread mutex, which could deadlock the scheduler).
-        current_task.death.assert_may_sleep();
-
-        // These transmutes do something fishy with a closure.
-        let f_fake_region = unsafe {
-            transmute::<|&mut Scheduler, ~Task|,
-                        |&mut Scheduler, ~Task|>(f)
+        let current_task_dupe = unsafe {
+            *cast::transmute::<&~GreenTask, &uint>(&current_task)
         };
-        let f_opaque = ClosureConverter::from_fn(f_fake_region);
 
         // The current task is placed inside an enum with the cleanup
         // function. This enum is then placed inside the scheduler.
         self.cleanup_job = Some(CleanupJob::new(current_task, f_opaque));
 
         // The scheduler is then placed inside the next task.
-        let mut next_task = next_task;
         next_task.sched = Some(self);
 
         // However we still need an internal mutable pointer to the
@@ -607,12 +596,12 @@ impl Scheduler {
         unsafe {
 
             let sched: &mut Scheduler =
-                transmute_mut_region(*next_task.sched.get_mut_ref());
+                cast::transmute_mut_region(*next_task.sched.get_mut_ref());
 
-            let current_task: &mut Task = match sched.cleanup_job {
+            let current_task: &mut GreenTask = match sched.cleanup_job {
                 Some(CleanupJob { task: ref task, .. }) => {
-                    let task_ptr: *~Task = task;
-                    transmute_mut_region(*transmute_mut_unsafe(task_ptr))
+                    let task_ptr: *~GreenTask = task;
+                    cast::transmute_mut_region(*cast::transmute_mut_unsafe(task_ptr))
                 }
                 None => {
                     rtabort!("no cleanup job");
@@ -626,7 +615,7 @@ impl Scheduler {
             // works because due to transmute the borrow checker
             // believes that we have no internal pointers to
             // next_task.
-            Local::put(next_task);
+            cast::forget(next_task);
 
             // The raw context swap operation. The next action taken
             // will be running the cleanup job from the context of the
@@ -637,16 +626,19 @@ impl Scheduler {
         // When the context swaps back to this task we immediately
         // run the cleanup job, as expected by the previously called
         // swap_contexts function.
-        unsafe {
-            let task: *mut Task = Local::unsafe_borrow();
-            (*task).sched.get_mut_ref().run_cleanup_job();
+        let mut current_task: ~GreenTask = unsafe {
+            cast::transmute(current_task_dupe)
+        };
+        current_task.sched.get_mut_ref().run_cleanup_job();
 
-            // See the comments in switch_running_tasks_and_then for why a lock
-            // is acquired here. This is the resumption points and the "bounce"
-            // that it is referring to.
-            (*task).nasty_deschedule_lock.lock();
-            (*task).nasty_deschedule_lock.unlock();
+        // See the comments in switch_running_tasks_and_then for why a lock
+        // is acquired here. This is the resumption points and the "bounce"
+        // that it is referring to.
+        unsafe {
+            current_task.nasty_deschedule_lock.lock();
+            current_task.nasty_deschedule_lock.unlock();
         }
+        return current_task;
     }
 
     // Returns a mutable reference to both contexts involved in this
@@ -654,37 +646,33 @@ impl Scheduler {
     // references to keep even when we don't own the tasks. It looks
     // kinda safe because we are doing transmutes before passing in
     // the arguments.
-    pub fn get_contexts<'a>(current_task: &mut Task, next_task: &mut Task) ->
+    pub fn get_contexts<'a>(current_task: &mut GreenTask, next_task: &mut GreenTask) ->
         (&'a mut Context, &'a mut Context) {
         let current_task_context =
             &mut current_task.coroutine.get_mut_ref().saved_context;
         let next_task_context =
                 &mut next_task.coroutine.get_mut_ref().saved_context;
         unsafe {
-            (transmute_mut_region(current_task_context),
-             transmute_mut_region(next_task_context))
+            (cast::transmute_mut_region(current_task_context),
+             cast::transmute_mut_region(next_task_context))
         }
     }
 
     // * Context Swapping Helpers - Here be ugliness!
 
-    pub fn resume_task_immediately(~self, task: ~Task) {
-        self.change_task_context(task, |sched, stask| {
+    pub fn resume_task_immediately(~self, cur: ~GreenTask,
+                                   next: ~GreenTask) -> ~GreenTask {
+        assert!(cur.is_sched());
+        self.change_task_context(cur, next, |sched, stask| {
+            assert!(sched.sched_task.is_none());
             sched.sched_task = Some(stask);
         })
     }
 
     fn resume_task_immediately_cl(sched: ~Scheduler,
-                                  task: ~Task) {
-        sched.resume_task_immediately(task)
-    }
-
-
-    pub fn resume_blocked_task_immediately(~self, blocked_task: BlockedTask) {
-        match blocked_task.wake() {
-            Some(task) => { self.resume_task_immediately(task); }
-            None => Local::put(self)
-        };
+                                  cur: ~GreenTask,
+                                  next: ~GreenTask) {
+        sched.resume_task_immediately(cur, next).put()
     }
 
     /// Block a running task, context switch to the scheduler, then pass the
@@ -709,15 +697,18 @@ impl Scheduler {
     /// guaranteed that this function will not return before the given closure
     /// has returned.
     pub fn deschedule_running_task_and_then(mut ~self,
+                                            cur: ~GreenTask,
                                             f: |&mut Scheduler, BlockedTask|) {
         // Trickier - we need to get the scheduler task out of self
         // and use it as the destination.
         let stask = self.sched_task.take_unwrap();
         // Otherwise this is the same as below.
-        self.switch_running_tasks_and_then(stask, f);
+        self.switch_running_tasks_and_then(cur, stask, f)
     }
 
-    pub fn switch_running_tasks_and_then(~self, next_task: ~Task,
+    pub fn switch_running_tasks_and_then(~self,
+                                         cur: ~GreenTask,
+                                         next: ~GreenTask,
                                          f: |&mut Scheduler, BlockedTask|) {
         // And here comes one of the sad moments in which a lock is used in a
         // core portion of the rust runtime. As always, this is highly
@@ -733,80 +724,99 @@ impl Scheduler {
         // task-local lock around this block. The resumption of the task in
         // context switching will bounce on the lock, thereby waiting for this
         // block to finish, eliminating the race mentioned above.
+        // fail!("should never return!");
         //
         // To actually maintain a handle to the lock, we use an unsafe pointer
         // to it, but we're guaranteed that the task won't exit until we've
         // unlocked the lock so there's no worry of this memory going away.
-        self.change_task_context(next_task, |sched, mut task| {
+        let cur = self.change_task_context(cur, next, |sched, mut task| {
             let lock: *mut Mutex = &mut task.nasty_deschedule_lock;
             unsafe { (*lock).lock() }
-            f(sched, BlockedTask::block(task));
+            f(sched, BlockedTask::block(task.swap()));
             unsafe { (*lock).unlock() }
-        })
+        });
+        cur.put();
     }
 
-    fn switch_task(sched: ~Scheduler, task: ~Task) {
-        sched.switch_running_tasks_and_then(task, |sched, last_task| {
-            sched.enqueue_blocked_task(last_task);
-        });
+    fn switch_task(sched: ~Scheduler, cur: ~GreenTask, next: ~GreenTask) {
+        sched.change_task_context(cur, next, |sched, last_task| {
+            if last_task.is_sched() {
+                assert!(sched.sched_task.is_none());
+                sched.sched_task = Some(last_task);
+            } else {
+                sched.enqueue_task(last_task);
+            }
+        }).put()
     }
 
     // * Task Context Helpers
 
     /// Called by a running task to end execution, after which it will
     /// be recycled by the scheduler for reuse in a new task.
-    pub fn terminate_current_task(mut ~self) {
+    pub fn terminate_current_task(mut ~self, cur: ~GreenTask) {
         // Similar to deschedule running task and then, but cannot go through
         // the task-blocking path. The task is already dying.
         let stask = self.sched_task.take_unwrap();
-        self.change_task_context(stask, |sched, mut dead_task| {
+        let _cur = self.change_task_context(cur, stask, |sched, mut dead_task| {
             let coroutine = dead_task.coroutine.take_unwrap();
             coroutine.recycle(&mut sched.stack_pool);
-        })
+        });
+        fail!("should never return!");
     }
 
-    pub fn run_task(task: ~Task) {
-        let sched: ~Scheduler = Local::take();
-        sched.process_task(task, Scheduler::switch_task);
+    pub fn run_task(~self, cur: ~GreenTask, next: ~GreenTask) {
+        self.process_task(cur, next, Scheduler::switch_task);
     }
 
-    pub fn run_task_later(next_task: ~Task) {
-        let mut sched = Local::borrow(None::<Scheduler>);
-        sched.get().enqueue_task(next_task);
+    pub fn run_task_later(mut cur: ~GreenTask, next: ~GreenTask) {
+        let mut sched = cur.sched.take_unwrap();
+        sched.enqueue_task(next);
+        cur.put_with_sched(sched);
     }
 
     /// Yield control to the scheduler, executing another task. This is guaranteed
     /// to introduce some amount of randomness to the scheduler. Currently the
     /// randomness is a result of performing a round of work stealing (which
     /// may end up stealing from the current scheduler).
-    pub fn yield_now(mut ~self) {
-        self.yield_check_count = reset_yield_check(&mut self.rng);
-        // Tell the scheduler to start stealing on the next iteration
-        self.steal_for_yield = true;
-        self.deschedule_running_task_and_then(|sched, task| {
-            sched.enqueue_blocked_task(task);
-        })
+    pub fn yield_now(mut ~self, cur: ~GreenTask) {
+        // Async handles trigger the scheduler by calling yield_now on the local
+        // task, which eventually gets us to here. See comments in SchedRunner
+        // for more info on this.
+        if cur.is_sched() {
+            assert!(self.sched_task.is_none());
+            self.run_sched_once(cur);
+        } else {
+            self.yield_check_count = reset_yield_check(&mut self.rng);
+            // Tell the scheduler to start stealing on the next iteration
+            self.steal_for_yield = true;
+            let stask = self.sched_task.take_unwrap();
+            let cur = self.change_task_context(cur, stask, |sched, task| {
+                sched.enqueue_task(task);
+            });
+            cur.put()
+        }
     }
 
-    pub fn maybe_yield(mut ~self) {
-        // The number of times to do the yield check before yielding, chosen arbitrarily.
+    pub fn maybe_yield(mut ~self, cur: ~GreenTask) {
+        // The number of times to do the yield check before yielding, chosen
+        // arbitrarily.
         rtassert!(self.yield_check_count > 0);
         self.yield_check_count -= 1;
         if self.yield_check_count == 0 {
-            self.yield_now();
+            self.yield_now(cur);
         } else {
-            Local::put(self);
+            cur.put_with_sched(self);
         }
     }
 
 
     // * Utility Functions
 
-    pub fn sched_id(&self) -> uint { to_uint(self) }
+    pub fn sched_id(&self) -> uint { unsafe { cast::transmute(self) } }
 
     pub fn run_cleanup_job(&mut self) {
         let cleanup_job = self.cleanup_job.take_unwrap();
-        cleanup_job.run(self);
+        cleanup_job.run(self)
     }
 
     pub fn make_handle(&mut self) -> SchedHandle {
@@ -816,20 +826,21 @@ impl Scheduler {
             remote: remote,
             queue: self.message_producer.clone(),
             sched_id: self.sched_id()
-        };
+        }
     }
 }
 
 // Supporting types
 
-type SchedulingFn = extern "Rust" fn (~Scheduler, ~Task);
+type SchedulingFn = extern "Rust" fn (~Scheduler, ~GreenTask, ~GreenTask);
 
 pub enum SchedMessage {
     Wake,
     Shutdown,
-    PinnedTask(~Task),
-    TaskFromFriend(~Task),
-    RunOnce(~Task),
+    NewNeighbor(deque::Stealer<~GreenTask>),
+    PinnedTask(~GreenTask),
+    TaskFromFriend(~GreenTask),
+    RunOnce(~GreenTask),
 }
 
 pub struct SchedHandle {
@@ -849,17 +860,28 @@ struct SchedRunner;
 
 impl Callback for SchedRunner {
     fn call(&mut self) {
-        Scheduler::run_sched_once();
+        // In theory, this function needs to invoke the `run_sched_once`
+        // function on the scheduler. Sadly, we have no context here, except for
+        // knowledge of the local `Task`. In order to avoid a call to
+        // `GreenTask::convert`, we just call `yield_now` and the scheduler will
+        // detect when a sched task performs a yield vs a green task performing
+        // a yield (and act accordingly).
+        //
+        // This function could be converted to `GreenTask::convert` if
+        // absolutely necessary, but for cleanliness it is much better to not
+        // use the conversion function.
+        let task: ~Task = Local::take();
+        task.yield_now();
     }
 }
 
 struct CleanupJob {
-    task: ~Task,
+    task: ~GreenTask,
     f: UnsafeTaskReceiver
 }
 
 impl CleanupJob {
-    pub fn new(task: ~Task, f: UnsafeTaskReceiver) -> CleanupJob {
+    pub fn new(task: ~GreenTask, f: UnsafeTaskReceiver) -> CleanupJob {
         CleanupJob {
             task: task,
             f: f
@@ -876,14 +898,16 @@ impl CleanupJob {
 // complaining
 type UnsafeTaskReceiver = raw::Closure;
 trait ClosureConverter {
-    fn from_fn(|&mut Scheduler, ~Task|) -> Self;
-    fn to_fn(self) -> |&mut Scheduler, ~Task|;
+    fn from_fn(|&mut Scheduler, ~GreenTask|) -> Self;
+    fn to_fn(self) -> |&mut Scheduler, ~GreenTask|;
 }
 impl ClosureConverter for UnsafeTaskReceiver {
-    fn from_fn(f: |&mut Scheduler, ~Task|) -> UnsafeTaskReceiver {
-        unsafe { transmute(f) }
+    fn from_fn(f: |&mut Scheduler, ~GreenTask|) -> UnsafeTaskReceiver {
+        unsafe { cast::transmute(f) }
+    }
+    fn to_fn(self) -> |&mut Scheduler, ~GreenTask| {
+        unsafe { cast::transmute(self) }
     }
-    fn to_fn(self) -> |&mut Scheduler, ~Task| { unsafe { transmute(self) } }
 }
 
 // On unix, we read randomness straight from /dev/urandom, but the
@@ -897,12 +921,9 @@ fn new_sched_rng() -> XorShiftRng {
 }
 #[cfg(unix)]
 fn new_sched_rng() -> XorShiftRng {
-    use libc;
-    use mem;
-    use c_str::ToCStr;
-    use vec::MutableVector;
-    use iter::Iterator;
-    use rand::SeedableRng;
+    use std::libc;
+    use std::mem;
+    use std::rand::SeedableRng;
 
     let fd = "/dev/urandom".with_c_str(|name| {
         unsafe { libc::open(name, libc::O_RDONLY, 0) }
@@ -933,24 +954,47 @@ fn new_sched_rng() -> XorShiftRng {
 
 #[cfg(test)]
 mod test {
-    use prelude::*;
+    use std::task::TaskOpts;
+    use std::rt::Runtime;
+    use std::rt::task::Task;
+    use std::rt::local::Local;
 
-    use borrow::to_uint;
-    use rt::deque::BufferPool;
-    use rt::basic;
-    use rt::sched::{Scheduler};
-    use rt::task::{Task, Sched};
-    use rt::test::*;
-    use rt::thread::Thread;
-    use rt::util;
-    use task::TaskResult;
-    use unstable::run_in_bare_thread;
+    use basic;
+    use sched::{TaskFromFriend, PinnedTask};
+    use task::{GreenTask, HomeSched};
+    use PoolConfig;
+    use SchedPool;
+
+    fn pool() -> SchedPool {
+        SchedPool::new(PoolConfig {
+            threads: 1,
+            event_loop_factory: Some(basic::event_loop),
+        })
+    }
+
+    fn run(f: proc()) {
+        let mut pool = pool();
+        pool.spawn(TaskOpts::new(), f);
+        pool.shutdown();
+    }
+
+    fn sched_id() -> uint {
+        let mut task = Local::borrow(None::<Task>);
+        match task.get().maybe_take_runtime::<GreenTask>() {
+            Some(green) => {
+                let ret = green.sched.get_ref().sched_id();
+                task.get().put_runtime(green as ~Runtime);
+                return ret;
+            }
+            None => fail!()
+        }
+    }
 
     #[test]
     fn trivial_run_in_newsched_task_test() {
         let mut task_ran = false;
         let task_ran_ptr: *mut bool = &mut task_ran;
-        do run_in_newsched_task || {
+        do run {
             unsafe { *task_ran_ptr = true };
             rtdebug!("executed from the new scheduler")
         }
@@ -962,9 +1006,11 @@ mod test {
         let total = 10;
         let mut task_run_count = 0;
         let task_run_count_ptr: *mut uint = &mut task_run_count;
-        do run_in_newsched_task || {
+        // with only one thread this is safe to run in without worries of
+        // contention.
+        do run {
             for _ in range(0u, total) {
-                do spawntask || {
+                do spawn || {
                     unsafe { *task_run_count_ptr = *task_run_count_ptr + 1};
                 }
             }
@@ -976,12 +1022,12 @@ mod test {
     fn multiple_task_nested_test() {
         let mut task_run_count = 0;
         let task_run_count_ptr: *mut uint = &mut task_run_count;
-        do run_in_newsched_task || {
-            do spawntask || {
+        do run {
+            do spawn {
                 unsafe { *task_run_count_ptr = *task_run_count_ptr + 1 };
-                do spawntask || {
+                do spawn {
                     unsafe { *task_run_count_ptr = *task_run_count_ptr + 1 };
-                    do spawntask || {
+                    do spawn {
                         unsafe { *task_run_count_ptr = *task_run_count_ptr + 1 };
                     }
                 }
@@ -990,52 +1036,33 @@ mod test {
         assert!(task_run_count == 3);
     }
 
-    // Confirm that a sched_id actually is the uint form of the
-    // pointer to the scheduler struct.
-    #[test]
-    fn simple_sched_id_test() {
-        do run_in_bare_thread {
-            let sched = ~new_test_uv_sched();
-            assert!(to_uint(sched) == sched.sched_id());
-        }
-    }
-
-    // Compare two scheduler ids that are different, this should never
-    // fail but may catch a mistake someday.
-    #[test]
-    fn compare_sched_id_test() {
-        do run_in_bare_thread {
-            let sched_one = ~new_test_uv_sched();
-            let sched_two = ~new_test_uv_sched();
-            assert!(sched_one.sched_id() != sched_two.sched_id());
-        }
-    }
-
-
     // A very simple test that confirms that a task executing on the
     // home scheduler notices that it is home.
     #[test]
     fn test_home_sched() {
-        do run_in_bare_thread {
-            let mut task_ran = false;
-            let task_ran_ptr: *mut bool = &mut task_ran;
+        let mut pool = pool();
 
-            let mut sched = ~new_test_uv_sched();
-            let sched_handle = sched.make_handle();
+        let (dport, dchan) = Chan::new();
+        {
+            let (port, chan) = Chan::new();
+            let mut handle1 = pool.spawn_sched();
+            let mut handle2 = pool.spawn_sched();
 
-            let mut task = ~do Task::new_root_homed(&mut sched.stack_pool, None,
-                                                Sched(sched_handle)) {
-                unsafe { *task_ran_ptr = true };
-                assert!(Task::on_appropriate_sched());
+            handle1.send(TaskFromFriend(do pool.task(TaskOpts::new()) {
+                chan.send(sched_id());
+            }));
+            let sched1_id = port.recv();
+
+            let mut task = do pool.task(TaskOpts::new()) {
+                assert_eq!(sched_id(), sched1_id);
+                dchan.send(());
             };
-
-            let on_exit: proc(TaskResult) = proc(exit_status) {
-                rtassert!(exit_status.is_ok())
-            };
-            task.death.on_exit = Some(on_exit);
-
-            sched.bootstrap(task);
+            task.give_home(HomeSched(handle1));
+            handle2.send(TaskFromFriend(task));
         }
+        dport.recv();
+
+        pool.shutdown();
     }
 
     // An advanced test that checks all four possible states that a
@@ -1043,12 +1070,13 @@ mod test {
 
     #[test]
     fn test_schedule_home_states() {
-        use rt::sleeper_list::SleeperList;
-        use rt::sched::Shutdown;
-        use borrow;
+        use sleeper_list::SleeperList;
+        use super::{Shutdown, Scheduler, SchedHandle};
+        use std::unstable::run_in_bare_thread;
+        use std::rt::thread::Thread;
+        use std::sync::deque::BufferPool;
 
         do run_in_bare_thread {
-
             let sleepers = SleeperList::new();
             let mut pool = BufferPool::new();
             let (normal_worker, normal_stealer) = pool.deque();
@@ -1057,17 +1085,18 @@ mod test {
 
             // Our normal scheduler
             let mut normal_sched = ~Scheduler::new(
+                1,
                 basic::event_loop(),
                 normal_worker,
                 queues.clone(),
                 sleepers.clone());
 
             let normal_handle = normal_sched.make_handle();
-
             let friend_handle = normal_sched.make_handle();
 
             // Our special scheduler
             let mut special_sched = ~Scheduler::new_special(
+                1,
                 basic::event_loop(),
                 special_worker,
                 queues.clone(),
@@ -1086,35 +1115,61 @@ mod test {
             //   3) task not homed, sched requeues
             //   4) task not home, send home
 
-            let task1 = ~do Task::new_root_homed(&mut special_sched.stack_pool, None,
-                                                 Sched(t1_handle)) || {
-                rtassert!(Task::on_appropriate_sched());
-            };
-            rtdebug!("task1 id: **{}**", borrow::to_uint(task1));
+            // Grab both the scheduler and the task from TLS and check if the
+            // task is executing on an appropriate scheduler.
+            fn on_appropriate_sched() -> bool {
+                use task::{TypeGreen, TypeSched, HomeSched};
+                let task = GreenTask::convert(Local::take());
+                let sched_id = task.sched.get_ref().sched_id();
+                let run_any = task.sched.get_ref().run_anything;
+                let ret = match task.task_type {
+                    TypeGreen(Some(AnySched)) => {
+                        run_any
+                    }
+                    TypeGreen(Some(HomeSched(SchedHandle {
+                        sched_id: ref id,
+                        ..
+                    }))) => {
+                        *id == sched_id
+                    }
+                    TypeGreen(None) => { fail!("task without home"); }
+                    TypeSched => { fail!("expected green task"); }
+                };
+                task.put();
+                ret
+            }
 
-            let task2 = ~do Task::new_root(&mut normal_sched.stack_pool, None) {
-                rtassert!(Task::on_appropriate_sched());
+            let task1 = do GreenTask::new_homed(&mut special_sched.stack_pool,
+                                                None, HomeSched(t1_handle)) {
+                rtassert!(on_appropriate_sched());
             };
 
-            let task3 = ~do Task::new_root(&mut normal_sched.stack_pool, None) {
-                rtassert!(Task::on_appropriate_sched());
+            let task2 = do GreenTask::new(&mut normal_sched.stack_pool, None) {
+                rtassert!(on_appropriate_sched());
             };
 
-            let task4 = ~do Task::new_root_homed(&mut special_sched.stack_pool, None,
-                                                 Sched(t4_handle)) {
-                rtassert!(Task::on_appropriate_sched());
+            let task3 = do GreenTask::new(&mut normal_sched.stack_pool, None) {
+                rtassert!(on_appropriate_sched());
+            };
+
+            let task4 = do GreenTask::new_homed(&mut special_sched.stack_pool,
+                                                None, HomeSched(t4_handle)) {
+                rtassert!(on_appropriate_sched());
             };
-            rtdebug!("task4 id: **{}**", borrow::to_uint(task4));
 
             // Signal from the special task that we are done.
             let (port, chan) = Chan::<()>::new();
 
-            let normal_task = ~do Task::new_root(&mut normal_sched.stack_pool, None) {
-                rtdebug!("*about to submit task2*");
-                Scheduler::run_task(task2);
-                rtdebug!("*about to submit task4*");
-                Scheduler::run_task(task4);
-                rtdebug!("*normal_task done*");
+            fn run(next: ~GreenTask) {
+                let mut task = GreenTask::convert(Local::take());
+                let sched = task.sched.take_unwrap();
+                sched.run_task(task, next)
+            }
+
+            let normal_task = do GreenTask::new(&mut normal_sched.stack_pool,
+                                                None) {
+                run(task2);
+                run(task4);
                 port.recv();
                 let mut nh = normal_handle;
                 nh.send(Shutdown);
@@ -1122,29 +1177,23 @@ mod test {
                 sh.send(Shutdown);
             };
 
-            rtdebug!("normal task: {}", borrow::to_uint(normal_task));
 
-            let special_task = ~do Task::new_root(&mut special_sched.stack_pool, None) {
-                rtdebug!("*about to submit task1*");
-                Scheduler::run_task(task1);
-                rtdebug!("*about to submit task3*");
-                Scheduler::run_task(task3);
-                rtdebug!("*done with special_task*");
+            let special_task = do GreenTask::new(&mut special_sched.stack_pool,
+                                                 None) {
+                run(task1);
+                run(task3);
                 chan.send(());
             };
 
-            rtdebug!("special task: {}", borrow::to_uint(special_task));
 
             let normal_sched = normal_sched;
             let normal_thread = do Thread::start {
                 normal_sched.bootstrap(normal_task);
-                rtdebug!("finished with normal_thread");
             };
 
             let special_sched = special_sched;
             let special_thread = do Thread::start {
                 special_sched.bootstrap(special_task);
-                rtdebug!("finished with special_sched");
             };
 
             normal_thread.join();
@@ -1152,109 +1201,82 @@ mod test {
         }
     }
 
-    #[test]
-    fn test_stress_schedule_task_states() {
-        if util::limit_thread_creation_due_to_osx_and_valgrind() { return; }
-        let n = stress_factor() * 120;
-        for _ in range(0, n as int) {
-            test_schedule_home_states();
-        }
-    }
+    //#[test]
+    //fn test_stress_schedule_task_states() {
+    //    if util::limit_thread_creation_due_to_osx_and_valgrind() { return; }
+    //    let n = stress_factor() * 120;
+    //    for _ in range(0, n as int) {
+    //        test_schedule_home_states();
+    //    }
+    //}
 
     #[test]
     fn test_io_callback() {
-        use io::timer;
+        use std::io::timer;
 
-        // This is a regression test that when there are no schedulable tasks
-        // in the work queue, but we are performing I/O, that once we do put
-        // something in the work queue again the scheduler picks it up and doesn't
-        // exit before emptying the work queue
-        do run_in_uv_task {
-            do spawntask {
+        let mut pool = SchedPool::new(PoolConfig {
+            threads: 2,
+            event_loop_factory: None,
+        });
+
+        // This is a regression test that when there are no schedulable tasks in
+        // the work queue, but we are performing I/O, that once we do put
+        // something in the work queue again the scheduler picks it up and
+        // doesn't exit before emptying the work queue
+        do pool.spawn(TaskOpts::new()) {
+            do spawn {
                 timer::sleep(10);
             }
         }
+
+        pool.shutdown();
     }
 
     #[test]
-    fn handle() {
-        do run_in_bare_thread {
-            let (port, chan) = Chan::new();
+    fn wakeup_across_scheds() {
+        let (port1, chan1) = Chan::new();
+        let (port2, chan2) = Chan::new();
 
-            let thread_one = do Thread::start {
-                let chan = chan;
-                do run_in_newsched_task_core {
-                    chan.send(());
-                }
-            };
+        let mut pool1 = pool();
+        let mut pool2 = pool();
 
-            let thread_two = do Thread::start {
-                let port = port;
-                do run_in_newsched_task_core {
-                    port.recv();
-                }
-            };
-
-            thread_two.join();
-            thread_one.join();
+        do pool1.spawn(TaskOpts::new()) {
+            let id = sched_id();
+            chan1.send(());
+            port2.recv();
+            assert_eq!(id, sched_id());
         }
+
+        do pool2.spawn(TaskOpts::new()) {
+            let id = sched_id();
+            port1.recv();
+            assert_eq!(id, sched_id());
+            chan2.send(());
+        }
+
+        pool1.shutdown();
+        pool2.shutdown();
     }
 
     // A regression test that the final message is always handled.
     // Used to deadlock because Shutdown was never recvd.
     #[test]
     fn no_missed_messages() {
-        use rt::sleeper_list::SleeperList;
-        use rt::stack::StackPool;
-        use rt::sched::{Shutdown, TaskFromFriend};
+        let mut pool = pool();
 
-        do run_in_bare_thread {
-            stress_factor().times(|| {
-                let sleepers = SleeperList::new();
-                let mut pool = BufferPool::new();
-                let (worker, stealer) = pool.deque();
+        let task = pool.task(TaskOpts::new(), proc()());
+        pool.spawn_sched().send(TaskFromFriend(task));
 
-                let mut sched = ~Scheduler::new(
-                    basic::event_loop(),
-                    worker,
-                    ~[stealer],
-                    sleepers.clone());
-
-                let mut handle = sched.make_handle();
-
-                let sched = sched;
-                let thread = do Thread::start {
-                    let mut sched = sched;
-                    let bootstrap_task =
-                        ~Task::new_root(&mut sched.stack_pool,
-                                        None,
-                                        proc()());
-                    sched.bootstrap(bootstrap_task);
-                };
-
-                let mut stack_pool = StackPool::new();
-                let task = ~Task::new_root(&mut stack_pool, None, proc()());
-                handle.send(TaskFromFriend(task));
-
-                handle.send(Shutdown);
-                drop(handle);
-
-                thread.join();
-            })
-        }
+        pool.shutdown();
     }
 
     #[test]
     fn multithreading() {
-        use num::Times;
-        use vec::OwnedVector;
-        use container::Container;
-
-        do run_in_mt_newsched_task {
+        do run {
             let mut ports = ~[];
             10.times(|| {
                 let (port, chan) = Chan::new();
-                do spawntask_later {
+                do spawn {
                     chan.send(());
                 }
                 ports.push(port);
@@ -1268,7 +1290,7 @@ mod test {
 
      #[test]
     fn thread_ring() {
-        do run_in_mt_newsched_task {
+        do run {
             let (end_port, end_chan) = Chan::new();
 
             let n_tasks = 10;
@@ -1281,14 +1303,14 @@ mod test {
                 let (next_p, ch) = Chan::new();
                 let imm_i = i;
                 let imm_p = p;
-                do spawntask_random {
+                do spawn {
                     roundtrip(imm_i, n_tasks, &imm_p, &ch);
                 };
                 p = next_p;
                 i += 1;
             }
             let p = p;
-            do spawntask_random {
+            do spawn {
                 roundtrip(1, n_tasks, &p, &ch1);
             }
 
@@ -1319,22 +1341,20 @@ mod test {
 
     #[test]
     fn start_closure_dtor() {
-        use ops::Drop;
-
         // Regression test that the `start` task entrypoint can
         // contain dtors that use task resources
-        do run_in_newsched_task {
+        do run {
             struct S { field: () }
 
             impl Drop for S {
                 fn drop(&mut self) {
-                    let _foo = @0;
+                    let _foo = ~0;
                 }
             }
 
             let s = S { field: () };
 
-            do spawntask {
+            do spawn {
                 let _ss = &s;
             }
         }
@@ -1344,52 +1364,120 @@ mod test {
     #[ignore]
     #[test]
     fn dont_starve_1() {
-        stress_factor().times(|| {
-            do run_in_mt_newsched_task {
-                let (port, chan) = Chan::new();
+        let mut pool = SchedPool::new(PoolConfig {
+            threads: 2, // this must be > 1
+            event_loop_factory: Some(basic::event_loop),
+        });
+        do pool.spawn(TaskOpts::new()) {
+            let (port, chan) = Chan::new();
 
-                // This task should not be able to starve the sender;
-                // The sender should get stolen to another thread.
-                do spawntask {
-                    while port.try_recv().is_none() { }
-                }
-
-                chan.send(());
+            // This task should not be able to starve the sender;
+            // The sender should get stolen to another thread.
+            do spawn {
+                while port.try_recv().is_none() { }
             }
-        })
+
+            chan.send(());
+        }
+        pool.shutdown();
     }
 
     #[test]
     fn dont_starve_2() {
-        stress_factor().times(|| {
-            do run_in_newsched_task {
-                let (port, chan) = Chan::new();
-                let (_port2, chan2) = Chan::new();
+        do run {
+            let (port, chan) = Chan::new();
+            let (_port2, chan2) = Chan::new();
 
-                // This task should not be able to starve the other task.
-                // The sends should eventually yield.
-                do spawntask {
-                    while port.try_recv().is_none() {
-                        chan2.send(());
+            // This task should not be able to starve the other task.
+            // The sends should eventually yield.
+            do spawn {
+                while port.try_recv().is_none() {
+                    chan2.send(());
+                }
+            }
+
+            chan.send(());
+        }
+    }
+
+    // Regression test for a logic bug that would cause single-threaded
+    // schedulers to sleep forever after yielding and stealing another task.
+    #[test]
+    fn single_threaded_yield() {
+        use std::task::deschedule;
+        do run {
+            5.times(deschedule);
+        }
+    }
+
+    #[test]
+    fn test_spawn_sched_blocking() {
+        use std::unstable::mutex::Mutex;
+
+        // Testing that a task in one scheduler can block in foreign code
+        // without affecting other schedulers
+        for _ in range(0, 20) {
+            let mut pool = pool();
+            let (start_po, start_ch) = Chan::new();
+            let (fin_po, fin_ch) = Chan::new();
+
+            let lock = unsafe { Mutex::new() };
+            let lock2 = unsafe { lock.clone() };
+
+            let mut handle = pool.spawn_sched();
+            handle.send(PinnedTask(pool.task(TaskOpts::new(), proc() {
+                let mut lock = lock2;
+                unsafe {
+                    lock.lock();
+
+                    start_ch.send(());
+                    lock.wait();   // block the scheduler thread
+                    lock.signal(); // let them know we have the lock
+                    lock.unlock();
+                }
+
+                fin_ch.send(());
+            })));
+            drop(handle);
+
+            let mut handle = pool.spawn_sched();
+            handle.send(TaskFromFriend(pool.task(TaskOpts::new(), proc() {
+                // Wait until the other task has its lock
+                start_po.recv();
+
+                fn pingpong(po: &Port<int>, ch: &Chan<int>) {
+                    let mut val = 20;
+                    while val > 0 {
+                        val = po.recv();
+                        ch.try_send(val - 1);
                     }
                 }
 
-                chan.send(());
-            }
-        })
-    }
+                let (setup_po, setup_ch) = Chan::new();
+                let (parent_po, parent_ch) = Chan::new();
+                do spawn {
+                    let (child_po, child_ch) = Chan::new();
+                    setup_ch.send(child_ch);
+                    pingpong(&child_po, &parent_ch);
+                };
 
-    // Regression test for a logic bug that would cause single-threaded schedulers
-    // to sleep forever after yielding and stealing another task.
-    #[test]
-    fn single_threaded_yield() {
-        use task::{spawn, spawn_sched, SingleThreaded, deschedule};
-        use num::Times;
+                let child_ch = setup_po.recv();
+                child_ch.send(20);
+                pingpong(&parent_po, &child_ch);
+                unsafe {
+                    let mut lock = lock;
+                    lock.lock();
+                    lock.signal();   // wakeup waiting scheduler
+                    lock.wait();     // wait for them to grab the lock
+                    lock.unlock();
+                    lock.destroy();  // now we're guaranteed they have no locks
+                }
+            })));
+            drop(handle);
 
-        do spawn_sched(SingleThreaded) {
-            5.times(|| { deschedule(); })
+            fin_po.recv();
+            pool.shutdown();
         }
-        do spawn { }
-        do spawn { }
+
     }
 }
diff --git a/src/libgreen/simple.rs b/src/libgreen/simple.rs
new file mode 100644
index 00000000000..4f904ee6e6d
--- /dev/null
+++ b/src/libgreen/simple.rs
@@ -0,0 +1,88 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A small module implementing a simple "runtime" used for bootstrapping a rust
+//! scheduler pool and then interacting with it.
+
+use std::cast;
+use std::rt::Runtime;
+use std::rt::local::Local;
+use std::rt::rtio;
+use std::rt::task::{Task, BlockedTask};
+use std::task::TaskOpts;
+use std::unstable::sync::LittleLock;
+
+struct SimpleTask {
+    lock: LittleLock,
+    awoken: bool,
+}
+
+impl Runtime for SimpleTask {
+    // Implement the simple tasks of descheduling and rescheduling, but only in
+    // a simple number of cases.
+    fn deschedule(mut ~self, times: uint, mut cur_task: ~Task,
+                  f: |BlockedTask| -> Result<(), BlockedTask>) {
+        assert!(times == 1);
+
+        let me = &mut *self as *mut SimpleTask;
+        let cur_dupe = &*cur_task as *Task;
+        cur_task.put_runtime(self as ~Runtime);
+        let task = BlockedTask::block(cur_task);
+
+        // See libnative/task.rs for what's going on here with the `awoken`
+        // field and the while loop around wait()
+        unsafe {
+            let mut guard = (*me).lock.lock();
+            (*me).awoken = false;
+            match f(task) {
+                Ok(()) => {
+                    while !(*me).awoken {
+                        guard.wait();
+                    }
+                }
+                Err(task) => { cast::forget(task.wake()); }
+            }
+            drop(guard);
+            cur_task = cast::transmute(cur_dupe);
+        }
+        Local::put(cur_task);
+    }
+    fn reawaken(mut ~self, mut to_wake: ~Task, _can_resched: bool) {
+        let me = &mut *self as *mut SimpleTask;
+        to_wake.put_runtime(self as ~Runtime);
+        unsafe {
+            cast::forget(to_wake);
+            let _l = (*me).lock.lock();
+            (*me).awoken = true;
+            (*me).lock.signal();
+        }
+    }
+
+    // These functions are all unimplemented and fail as a result. This is on
+    // purpose. A "simple task" is just that, a very simple task that can't
+    // really do a whole lot. The only purpose of the task is to get us off our
+    // feet and running.
+    fn yield_now(~self, _cur_task: ~Task) { fail!() }
+    fn maybe_yield(~self, _cur_task: ~Task) { fail!() }
+    fn spawn_sibling(~self, _cur_task: ~Task, _opts: TaskOpts, _f: proc()) {
+        fail!()
+    }
+    fn local_io<'a>(&'a mut self) -> Option<rtio::LocalIo<'a>> { None }
+    fn wrap(~self) -> ~Any { fail!() }
+}
+
+pub fn task() -> ~Task {
+    let mut task = ~Task::new();
+    task.put_runtime(~SimpleTask {
+        lock: LittleLock::new(),
+        awoken: false,
+    } as ~Runtime);
+    return task;
+}
diff --git a/src/libstd/rt/sleeper_list.rs b/src/libgreen/sleeper_list.rs
similarity index 92%
rename from src/libstd/rt/sleeper_list.rs
rename to src/libgreen/sleeper_list.rs
index 39c7431837f..5be260efdfa 100644
--- a/src/libstd/rt/sleeper_list.rs
+++ b/src/libgreen/sleeper_list.rs
@@ -11,10 +11,9 @@
 //! Maintains a shared list of sleeping schedulers. Schedulers
 //! use this to wake each other up.
 
-use rt::sched::SchedHandle;
-use rt::mpmc_bounded_queue::Queue;
-use option::*;
-use clone::Clone;
+use std::sync::mpmc_bounded_queue::Queue;
+
+use sched::SchedHandle;
 
 pub struct SleeperList {
     priv q: Queue<SchedHandle>,
diff --git a/src/libstd/rt/stack.rs b/src/libgreen/stack.rs
similarity index 95%
rename from src/libstd/rt/stack.rs
rename to src/libgreen/stack.rs
index 44b60e955d2..cf2a3d5f141 100644
--- a/src/libstd/rt/stack.rs
+++ b/src/libgreen/stack.rs
@@ -8,11 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use container::Container;
-use ptr::RawPtr;
-use vec;
-use ops::Drop;
-use libc::{c_uint, uintptr_t};
+use std::vec;
+use std::libc::{c_uint, uintptr_t};
 
 pub struct StackSegment {
     priv buf: ~[u8],
diff --git a/src/libgreen/task.rs b/src/libgreen/task.rs
new file mode 100644
index 00000000000..eff80df2a11
--- /dev/null
+++ b/src/libgreen/task.rs
@@ -0,0 +1,536 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The Green Task implementation
+//!
+//! This module contains the glue to the libstd runtime necessary to integrate
+//! M:N scheduling. This GreenTask structure is hidden as a trait object in all
+//! rust tasks and virtual calls are made in order to interface with it.
+//!
+//! Each green task contains a scheduler if it is currently running, and it also
+//! contains the rust task itself in order to juggle around ownership of the
+//! values.
+
+use std::cast;
+use std::rt::Runtime;
+use std::rt::rtio;
+use std::rt::local::Local;
+use std::rt::task::{Task, BlockedTask};
+use std::task::TaskOpts;
+use std::unstable::mutex::Mutex;
+
+use coroutine::Coroutine;
+use sched::{Scheduler, SchedHandle, RunOnce};
+use stack::StackPool;
+
+/// The necessary fields needed to keep track of a green task (as opposed to a
+/// 1:1 task).
+pub struct GreenTask {
+    coroutine: Option<Coroutine>,
+    handle: Option<SchedHandle>,
+    sched: Option<~Scheduler>,
+    task: Option<~Task>,
+    task_type: TaskType,
+    pool_id: uint,
+
+    // See the comments in the scheduler about why this is necessary
+    nasty_deschedule_lock: Mutex,
+}
+
+pub enum TaskType {
+    TypeGreen(Option<Home>),
+    TypeSched,
+}
+
+pub enum Home {
+    AnySched,
+    HomeSched(SchedHandle),
+}
+
+impl GreenTask {
+    /// Creates a new green task which is not homed to any particular scheduler
+    /// and will not have any contained Task structure.
+    pub fn new(stack_pool: &mut StackPool,
+               stack_size: Option<uint>,
+               start: proc()) -> ~GreenTask {
+        GreenTask::new_homed(stack_pool, stack_size, AnySched, start)
+    }
+
+    /// Creates a new task (like `new`), but specifies the home for new task.
+    pub fn new_homed(stack_pool: &mut StackPool,
+                     stack_size: Option<uint>,
+                     home: Home,
+                     start: proc()) -> ~GreenTask {
+        let mut ops = GreenTask::new_typed(None, TypeGreen(Some(home)));
+        let start = GreenTask::build_start_wrapper(start, ops.as_uint());
+        ops.coroutine = Some(Coroutine::new(stack_pool, stack_size, start));
+        return ops;
+    }
+
+    /// Creates a new green task with the specified coroutine and type, this is
+    /// useful when creating scheduler tasks.
+    pub fn new_typed(coroutine: Option<Coroutine>,
+                     task_type: TaskType) -> ~GreenTask {
+        ~GreenTask {
+            pool_id: 0,
+            coroutine: coroutine,
+            task_type: task_type,
+            sched: None,
+            handle: None,
+            nasty_deschedule_lock: unsafe { Mutex::new() },
+            task: Some(~Task::new()),
+        }
+    }
+
+    /// Creates a new green task with the given configuration options for the
+    /// contained Task object. The given stack pool is also used to allocate a
+    /// new stack for this task.
+    pub fn configure(pool: &mut StackPool,
+                     opts: TaskOpts,
+                     f: proc()) -> ~GreenTask {
+        let TaskOpts {
+            watched: _watched,
+            notify_chan, name, stack_size
+        } = opts;
+
+        let mut green = GreenTask::new(pool, stack_size, f);
+        {
+            let task = green.task.get_mut_ref();
+            task.name = name;
+            match notify_chan {
+                Some(chan) => {
+                    let on_exit = proc(task_result) { chan.send(task_result) };
+                    task.death.on_exit = Some(on_exit);
+                }
+                None => {}
+            }
+        }
+        return green;
+    }
+
+    /// Just like the `maybe_take_runtime` function, this function should *not*
+    /// exist. Usage of this function is _strongly_ discouraged. This is an
+    /// absolute last resort necessary for converting a libstd task to a green
+    /// task.
+    ///
+    /// This function will assert that the task is indeed a green task before
+    /// returning (and will kill the entire process if this is wrong).
+    pub fn convert(mut task: ~Task) -> ~GreenTask {
+        match task.maybe_take_runtime::<GreenTask>() {
+            Some(mut green) => {
+                green.put_task(task);
+                green
+            }
+            None => rtabort!("not a green task any more?"),
+        }
+    }
+
+    /// Builds a function which is the actual starting execution point for a
+    /// rust task. This function is the glue necessary to execute the libstd
+    /// task and then clean up the green thread after it exits.
+    ///
+    /// The second argument to this function is actually a transmuted copy of
+    /// the `GreenTask` pointer. Context switches in the scheduler silently
+    /// transfer ownership of the `GreenTask` to the other end of the context
+    /// switch, so because this is the first code that is running in this task,
+    /// it must first re-acquire ownership of the green task.
+    pub fn build_start_wrapper(start: proc(), ops: uint) -> proc() {
+        proc() {
+            // First code after swap to this new context. Run our
+            // cleanup job after we have re-acquired ownership of the green
+            // task.
+            let mut task: ~GreenTask = unsafe { GreenTask::from_uint(ops) };
+            task.sched.get_mut_ref().run_cleanup_job();
+
+            // Convert our green task to a libstd task and then execute the code
+            // requeted. This is the "try/catch" block for this green task and
+            // is the wrapper for *all* code run in the task.
+            let mut start = Some(start);
+            let task = task.swap().run(|| start.take_unwrap()());
+
+            // Once the function has exited, it's time to run the termination
+            // routine. This means we need to context switch one more time but
+            // clean ourselves up on the other end. Since we have no way of
+            // preserving a handle to the GreenTask down to this point, this
+            // unfortunately must call `GreenTask::convert`. In order to avoid
+            // this we could add a `terminate` function to the `Runtime` trait
+            // in libstd, but that seems less appropriate since the coversion
+            // method exists.
+            GreenTask::convert(task).terminate();
+        }
+    }
+
+    pub fn give_home(&mut self, new_home: Home) {
+        match self.task_type {
+            TypeGreen(ref mut home) => { *home = Some(new_home); }
+            TypeSched => rtabort!("type error: used SchedTask as GreenTask"),
+        }
+    }
+
+    pub fn take_unwrap_home(&mut self) -> Home {
+        match self.task_type {
+            TypeGreen(ref mut home) => home.take_unwrap(),
+            TypeSched => rtabort!("type error: used SchedTask as GreenTask"),
+        }
+    }
+
+    // New utility functions for homes.
+
+    pub fn is_home_no_tls(&self, sched: &Scheduler) -> bool {
+        match self.task_type {
+            TypeGreen(Some(AnySched)) => { false }
+            TypeGreen(Some(HomeSched(SchedHandle { sched_id: ref id, .. }))) => {
+                *id == sched.sched_id()
+            }
+            TypeGreen(None) => { rtabort!("task without home"); }
+            TypeSched => {
+                // Awe yea
+                rtabort!("type error: expected: TypeGreen, found: TaskSched");
+            }
+        }
+    }
+
+    pub fn homed(&self) -> bool {
+        match self.task_type {
+            TypeGreen(Some(AnySched)) => { false }
+            TypeGreen(Some(HomeSched(SchedHandle { .. }))) => { true }
+            TypeGreen(None) => {
+                rtabort!("task without home");
+            }
+            TypeSched => {
+                rtabort!("type error: expected: TypeGreen, found: TaskSched");
+            }
+        }
+    }
+
+    pub fn is_sched(&self) -> bool {
+        match self.task_type {
+            TypeGreen(..) => false, TypeSched => true,
+        }
+    }
+
+    // Unsafe functions for transferring ownership of this GreenTask across
+    // context switches
+
+    pub fn as_uint(&self) -> uint {
+        unsafe { cast::transmute(self) }
+    }
+
+    pub unsafe fn from_uint(val: uint) -> ~GreenTask { cast::transmute(val) }
+
+    // Runtime glue functions and helpers
+
+    pub fn put_with_sched(mut ~self, sched: ~Scheduler) {
+        assert!(self.sched.is_none());
+        self.sched = Some(sched);
+        self.put();
+    }
+
+    pub fn put_task(&mut self, task: ~Task) {
+        assert!(self.task.is_none());
+        self.task = Some(task);
+    }
+
+    pub fn swap(mut ~self) -> ~Task {
+        let mut task = self.task.take_unwrap();
+        task.put_runtime(self as ~Runtime);
+        return task;
+    }
+
+    pub fn put(~self) {
+        assert!(self.sched.is_some());
+        Local::put(self.swap());
+    }
+
+    fn terminate(mut ~self) {
+        let sched = self.sched.take_unwrap();
+        sched.terminate_current_task(self);
+    }
+
+    // This function is used to remotely wakeup this green task back on to its
+    // original pool of schedulers. In order to do so, each tasks arranges a
+    // SchedHandle upon descheduling to be available for sending itself back to
+    // the original pool.
+    //
+    // Note that there is an interesting transfer of ownership going on here. We
+    // must relinquish ownership of the green task, but then also send the task
+    // over the handle back to the original scheduler. In order to safely do
+    // this, we leverage the already-present "nasty descheduling lock". The
+    // reason for doing this is that each task will bounce on this lock after
+    // resuming after a context switch. By holding the lock over the enqueueing
+    // of the task, we're guaranteed that the SchedHandle's memory will be valid
+    // for this entire function.
+    //
+    // An alternative would include having incredibly cheaply cloneable handles,
+    // but right now a SchedHandle is something like 6 allocations, so it is
+    // *not* a cheap operation to clone a handle. Until the day comes that we
+    // need to optimize this, a lock should do just fine (it's completely
+    // uncontended except for when the task is rescheduled).
+    fn reawaken_remotely(mut ~self) {
+        unsafe {
+            let mtx = &mut self.nasty_deschedule_lock as *mut Mutex;
+            let handle = self.handle.get_mut_ref() as *mut SchedHandle;
+            (*mtx).lock();
+            (*handle).send(RunOnce(self));
+            (*mtx).unlock();
+        }
+    }
+}
+
+impl Runtime for GreenTask {
+    fn yield_now(mut ~self, cur_task: ~Task) {
+        self.put_task(cur_task);
+        let sched = self.sched.take_unwrap();
+        sched.yield_now(self);
+    }
+
+    fn maybe_yield(mut ~self, cur_task: ~Task) {
+        self.put_task(cur_task);
+        let sched = self.sched.take_unwrap();
+        sched.maybe_yield(self);
+    }
+
+    fn deschedule(mut ~self, times: uint, cur_task: ~Task,
+                  f: |BlockedTask| -> Result<(), BlockedTask>) {
+        self.put_task(cur_task);
+        let mut sched = self.sched.take_unwrap();
+
+        // In order for this task to be reawoken in all possible contexts, we
+        // may need a handle back in to the current scheduler. When we're woken
+        // up in anything other than the local scheduler pool, this handle is
+        // used to send this task back into the scheduler pool.
+        if self.handle.is_none() {
+            self.handle = Some(sched.make_handle());
+            self.pool_id = sched.pool_id;
+        }
+
+        // This code is pretty standard, except for the usage of
+        // `GreenTask::convert`. Right now if we use `reawaken` directly it will
+        // expect for there to be a task in local TLS, but that is not true for
+        // this deschedule block (because the scheduler must retain ownership of
+        // the task while the cleanup job is running). In order to get around
+        // this for now, we invoke the scheduler directly with the converted
+        // Task => GreenTask structure.
+        if times == 1 {
+            sched.deschedule_running_task_and_then(self, |sched, task| {
+                match f(task) {
+                    Ok(()) => {}
+                    Err(t) => {
+                        t.wake().map(|t| {
+                            sched.enqueue_task(GreenTask::convert(t))
+                        });
+                    }
+                }
+            });
+        } else {
+            sched.deschedule_running_task_and_then(self, |sched, task| {
+                for task in task.make_selectable(times) {
+                    match f(task) {
+                        Ok(()) => {},
+                        Err(task) => {
+                            task.wake().map(|t| {
+                                sched.enqueue_task(GreenTask::convert(t))
+                            });
+                            break
+                        }
+                    }
+                }
+            });
+        }
+    }
+
+    fn reawaken(mut ~self, to_wake: ~Task, can_resched: bool) {
+        self.put_task(to_wake);
+        assert!(self.sched.is_none());
+
+        // Waking up a green thread is a bit of a tricky situation. We have no
+        // guarantee about where the current task is running. The options we
+        // have for where this current task is running are:
+        //
+        //  1. Our original scheduler pool
+        //  2. Some other scheduler pool
+        //  3. Something that isn't a scheduler pool
+        //
+        // In order to figure out what case we're in, this is the reason that
+        // the `maybe_take_runtime` function exists. Using this function we can
+        // dynamically check to see which of these cases is the current
+        // situation and then dispatch accordingly.
+        //
+        // In case 1, we just use the local scheduler to resume ourselves
+        // immediately (if a rescheduling is possible).
+        //
+        // In case 2 and 3, we need to remotely reawaken ourself in order to be
+        // transplanted back to the correct scheduler pool.
+        let mut running_task: ~Task = Local::take();
+        match running_task.maybe_take_runtime::<GreenTask>() {
+            Some(mut running_green_task) => {
+                running_green_task.put_task(running_task);
+                let mut sched = running_green_task.sched.take_unwrap();
+
+                if sched.pool_id == self.pool_id {
+                    if can_resched {
+                        sched.run_task(running_green_task, self);
+                    } else {
+                        sched.enqueue_task(self);
+                        running_green_task.put_with_sched(sched);
+                    }
+                } else {
+                    self.reawaken_remotely();
+
+                    // put that thing back where it came from!
+                    running_green_task.put_with_sched(sched);
+                }
+            }
+            None => {
+                self.reawaken_remotely();
+                Local::put(running_task);
+            }
+        }
+    }
+
+    fn spawn_sibling(mut ~self, cur_task: ~Task, opts: TaskOpts, f: proc()) {
+        self.put_task(cur_task);
+
+        // Spawns a task into the current scheduler. We allocate the new task's
+        // stack from the scheduler's stack pool, and then configure it
+        // accordingly to `opts`. Afterwards we bootstrap it immediately by
+        // switching to it.
+        //
+        // Upon returning, our task is back in TLS and we're good to return.
+        let mut sched = self.sched.take_unwrap();
+        let sibling = GreenTask::configure(&mut sched.stack_pool, opts, f);
+        sched.run_task(self, sibling)
+    }
+
+    // Local I/O is provided by the scheduler's event loop
+    fn local_io<'a>(&'a mut self) -> Option<rtio::LocalIo<'a>> {
+        match self.sched.get_mut_ref().event_loop.io() {
+            Some(io) => Some(rtio::LocalIo::new(io)),
+            None => None,
+        }
+    }
+
+    fn wrap(~self) -> ~Any { self as ~Any }
+}
+
+impl Drop for GreenTask {
+    fn drop(&mut self) {
+        unsafe { self.nasty_deschedule_lock.destroy(); }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::rt::Runtime;
+    use std::rt::local::Local;
+    use std::rt::task::Task;
+    use std::task;
+    use std::task::TaskOpts;
+
+    use super::super::{PoolConfig, SchedPool};
+    use super::GreenTask;
+
+    fn spawn_opts(opts: TaskOpts, f: proc()) {
+        let mut pool = SchedPool::new(PoolConfig {
+            threads: 1,
+            event_loop_factory: None,
+        });
+        pool.spawn(opts, f);
+        pool.shutdown();
+    }
+
+    #[test]
+    fn smoke() {
+        let (p, c) = Chan::new();
+        do spawn_opts(TaskOpts::new()) {
+            c.send(());
+        }
+        p.recv();
+    }
+
+    #[test]
+    fn smoke_fail() {
+        let (p, c) = Chan::<()>::new();
+        do spawn_opts(TaskOpts::new()) {
+            let _c = c;
+            fail!()
+        }
+        assert_eq!(p.recv_opt(), None);
+    }
+
+    #[test]
+    fn smoke_opts() {
+        let mut opts = TaskOpts::new();
+        opts.name = Some(SendStrStatic("test"));
+        opts.stack_size = Some(20 * 4096);
+        let (p, c) = Chan::new();
+        opts.notify_chan = Some(c);
+        spawn_opts(opts, proc() {});
+        assert!(p.recv().is_ok());
+    }
+
+    #[test]
+    fn smoke_opts_fail() {
+        let mut opts = TaskOpts::new();
+        let (p, c) = Chan::new();
+        opts.notify_chan = Some(c);
+        spawn_opts(opts, proc() { fail!() });
+        assert!(p.recv().is_err());
+    }
+
+    #[test]
+    fn yield_test() {
+        let (p, c) = Chan::new();
+        do spawn_opts(TaskOpts::new()) {
+            10.times(task::deschedule);
+            c.send(());
+        }
+        p.recv();
+    }
+
+    #[test]
+    fn spawn_children() {
+        let (p, c) = Chan::new();
+        do spawn_opts(TaskOpts::new()) {
+            let (p, c2) = Chan::new();
+            do spawn {
+                let (p, c3) = Chan::new();
+                do spawn {
+                    c3.send(());
+                }
+                p.recv();
+                c2.send(());
+            }
+            p.recv();
+            c.send(());
+        }
+        p.recv();
+    }
+
+    #[test]
+    fn spawn_inherits() {
+        let (p, c) = Chan::new();
+        do spawn_opts(TaskOpts::new()) {
+            let c = c;
+            do spawn {
+                let mut task: ~Task = Local::take();
+                match task.maybe_take_runtime::<GreenTask>() {
+                    Some(ops) => {
+                        task.put_runtime(ops as ~Runtime);
+                    }
+                    None => fail!(),
+                }
+                Local::put(task);
+                c.send(());
+            }
+        }
+        p.recv();
+    }
+}
diff --git a/src/libstd/io/native/file.rs b/src/libnative/io/file.rs
similarity index 97%
rename from src/libstd/io/native/file.rs
rename to src/libnative/io/file.rs
index de2655303d6..c1a378c7e3c 100644
--- a/src/libstd/io/native/file.rs
+++ b/src/libnative/io/file.rs
@@ -10,28 +10,21 @@
 
 //! Blocking posix-based file I/O
 
-#[allow(non_camel_case_types)];
+use std::c_str::CString;
+use std::io::IoError;
+use std::io;
+use std::libc::c_int;
+use std::libc;
+use std::os;
+use std::rt::rtio;
+use std::unstable::intrinsics;
+use std::vec;
 
-use c_str::CString;
-use io::IoError;
-use io;
-use libc::c_int;
-use libc;
-use ops::Drop;
-use option::{Some, None, Option};
-use os;
-use path::{Path, GenericPath};
-use ptr::RawPtr;
-use result::{Result, Ok, Err};
-use rt::rtio;
 use super::IoResult;
-use unstable::intrinsics;
-use vec::ImmutableVector;
-use vec;
 
-#[cfg(windows)] use os::win32::{as_utf16_p, fill_utf16_buf_and_decode};
-#[cfg(windows)] use ptr;
-#[cfg(windows)] use str;
+#[cfg(windows)] use std::os::win32::{as_utf16_p, fill_utf16_buf_and_decode};
+#[cfg(windows)] use std::ptr;
+#[cfg(windows)] use std::str;
 
 fn keep_going(data: &[u8], f: |*u8, uint| -> i64) -> i64 {
     #[cfg(windows)] static eintr: int = 0; // doesn't matter
@@ -490,8 +483,8 @@ pub fn readdir(p: &CString) -> IoResult<~[Path]> {
     unsafe {
         #[cfg(not(windows))]
         unsafe fn get_list(p: &CString) -> IoResult<~[Path]> {
-            use libc::{dirent_t};
-            use libc::{opendir, readdir, closedir};
+            use std::libc::{dirent_t};
+            use std::libc::{opendir, readdir, closedir};
             extern {
                 fn rust_list_dir_val(ptr: *dirent_t) -> *libc::c_char;
             }
@@ -517,14 +510,14 @@ pub fn readdir(p: &CString) -> IoResult<~[Path]> {
 
         #[cfg(windows)]
         unsafe fn get_list(p: &CString) -> IoResult<~[Path]> {
-            use libc::consts::os::extra::INVALID_HANDLE_VALUE;
-            use libc::{wcslen, free};
-            use libc::funcs::extra::kernel32::{
+            use std::libc::consts::os::extra::INVALID_HANDLE_VALUE;
+            use std::libc::{wcslen, free};
+            use std::libc::funcs::extra::kernel32::{
                 FindFirstFileW,
                 FindNextFileW,
                 FindClose,
             };
-            use libc::types::os::arch::extra::HANDLE;
+            use std::libc::types::os::arch::extra::HANDLE;
             use os::win32::{
                 as_utf16_p
             };
@@ -906,12 +899,11 @@ pub fn utime(p: &CString, atime: u64, mtime: u64) -> IoResult<()> {
 
 #[cfg(test)]
 mod tests {
-    use io::native::file::{CFile, FileDesc};
-    use io;
-    use libc;
-    use os;
-    use result::Ok;
-    use rt::rtio::RtioFileStream;
+    use super::{CFile, FileDesc};
+    use std::io;
+    use std::libc;
+    use std::os;
+    use std::rt::rtio::RtioFileStream;
 
     #[ignore(cfg(target_os = "freebsd"))] // hmm, maybe pipes have a tiny buffer
     #[test]
diff --git a/src/libstd/io/native/mod.rs b/src/libnative/io/mod.rs
similarity index 92%
rename from src/libstd/io/native/mod.rs
rename to src/libnative/io/mod.rs
index d9dccc84f1c..32056215e7c 100644
--- a/src/libstd/io/native/mod.rs
+++ b/src/libnative/io/mod.rs
@@ -21,24 +21,21 @@
 //! play. The only dependencies of these modules are the normal system libraries
 //! that you would find on the respective platform.
 
-use c_str::CString;
-use comm::SharedChan;
-use libc::c_int;
-use libc;
-use option::{Option, None, Some};
-use os;
-use path::Path;
-use result::{Result, Ok, Err};
-use rt::rtio;
-use rt::rtio::{RtioTcpStream, RtioTcpListener, RtioUdpSocket, RtioUnixListener,
-               RtioPipe, RtioFileStream, RtioProcess, RtioSignal, RtioTTY,
-               CloseBehavior, RtioTimer};
-use io;
-use io::IoError;
-use io::net::ip::SocketAddr;
-use io::process::ProcessConfig;
-use io::signal::Signum;
-use ai = io::net::addrinfo;
+use std::c_str::CString;
+use std::comm::SharedChan;
+use std::libc::c_int;
+use std::libc;
+use std::os;
+use std::rt::rtio;
+use std::rt::rtio::{RtioTcpStream, RtioTcpListener, RtioUdpSocket,
+                    RtioUnixListener, RtioPipe, RtioFileStream, RtioProcess,
+                    RtioSignal, RtioTTY, CloseBehavior, RtioTimer};
+use std::io;
+use std::io::IoError;
+use std::io::net::ip::SocketAddr;
+use std::io::process::ProcessConfig;
+use std::io::signal::Signum;
+use ai = std::io::net::addrinfo;
 
 // Local re-exports
 pub use self::file::FileDesc;
@@ -223,6 +220,3 @@ impl rtio::IoFactory for IoFactory {
         Err(unimpl())
     }
 }
-
-pub static mut NATIVE_IO_FACTORY: IoFactory = IoFactory;
-
diff --git a/src/libstd/io/native/process.rs b/src/libnative/io/process.rs
similarity index 95%
rename from src/libstd/io/native/process.rs
rename to src/libnative/io/process.rs
index ef972dc4d0a..64ce9d7e348 100644
--- a/src/libstd/io/native/process.rs
+++ b/src/libnative/io/process.rs
@@ -8,18 +8,17 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use io;
-use libc::{pid_t, c_void, c_int};
-use libc;
-use os;
-use prelude::*;
-use ptr;
-use rt::rtio;
-use super::file;
-#[cfg(windows)]
-use cast;
+use std::io;
+use std::libc::{pid_t, c_void, c_int};
+use std::libc;
+use std::os;
+use std::ptr;
+use std::rt::rtio;
+use p = std::io::process;
 
-use p = io::process;
+#[cfg(windows)] use std::cast;
+
+use super::file;
 
 /**
  * A value representing a child process.
@@ -179,22 +178,22 @@ fn spawn_process_os(prog: &str, args: &[~str],
                     env: Option<~[(~str, ~str)]>,
                     dir: Option<&Path>,
                     in_fd: c_int, out_fd: c_int, err_fd: c_int) -> SpawnProcessResult {
-    use libc::types::os::arch::extra::{DWORD, HANDLE, STARTUPINFO};
-    use libc::consts::os::extra::{
+    use std::libc::types::os::arch::extra::{DWORD, HANDLE, STARTUPINFO};
+    use std::libc::consts::os::extra::{
         TRUE, FALSE,
         STARTF_USESTDHANDLES,
         INVALID_HANDLE_VALUE,
         DUPLICATE_SAME_ACCESS
     };
-    use libc::funcs::extra::kernel32::{
+    use std::libc::funcs::extra::kernel32::{
         GetCurrentProcess,
         DuplicateHandle,
         CloseHandle,
         CreateProcessA
     };
-    use libc::funcs::extra::msvcrt::get_osfhandle;
+    use std::libc::funcs::extra::msvcrt::get_osfhandle;
 
-    use mem;
+    use std::mem;
 
     unsafe {
 
@@ -256,10 +255,10 @@ fn spawn_process_os(prog: &str, args: &[~str],
             fail!("failure in CreateProcess: {}", *msg);
         }
 
-        // We close the thread handle because we don't care about keeping the
+        // We close the thread handle because std::we don't care about keeping the
         // thread id valid, and we aren't keeping the thread handle around to be
         // able to close it later. We don't close the process handle however
-        // because we want the process id to stay valid at least until the
+        // because std::we want the process id to stay valid at least until the
         // calling code closes the process handle.
         CloseHandle(pi.hThread);
 
@@ -362,8 +361,8 @@ fn spawn_process_os(prog: &str, args: &[~str],
                     env: Option<~[(~str, ~str)]>,
                     dir: Option<&Path>,
                     in_fd: c_int, out_fd: c_int, err_fd: c_int) -> SpawnProcessResult {
-    use libc::funcs::posix88::unistd::{fork, dup2, close, chdir, execvp};
-    use libc::funcs::bsd44::getdtablesize;
+    use std::libc::funcs::posix88::unistd::{fork, dup2, close, chdir, execvp};
+    use std::libc::funcs::bsd44::getdtablesize;
 
     mod rustrt {
         extern {
@@ -433,7 +432,7 @@ fn spawn_process_os(prog: &str, args: &[~str],
 
 #[cfg(unix)]
 fn with_argv<T>(prog: &str, args: &[~str], cb: |**libc::c_char| -> T) -> T {
-    use vec;
+    use std::vec;
 
     // We can't directly convert `str`s into `*char`s, as someone needs to hold
     // a reference to the intermediary byte buffers. So first build an array to
@@ -459,7 +458,7 @@ fn with_argv<T>(prog: &str, args: &[~str], cb: |**libc::c_char| -> T) -> T {
 
 #[cfg(unix)]
 fn with_envp<T>(env: Option<~[(~str, ~str)]>, cb: |*c_void| -> T) -> T {
-    use vec;
+    use std::vec;
 
     // On posixy systems we can pass a char** for envp, which is a
     // null-terminated array of "k=v\n" strings. Like `with_argv`, we have to
@@ -540,8 +539,8 @@ fn waitpid(pid: pid_t) -> int {
 
     #[cfg(windows)]
     fn waitpid_os(pid: pid_t) -> int {
-        use libc::types::os::arch::extra::DWORD;
-        use libc::consts::os::extra::{
+        use std::libc::types::os::arch::extra::DWORD;
+        use std::libc::consts::os::extra::{
             SYNCHRONIZE,
             PROCESS_QUERY_INFORMATION,
             FALSE,
@@ -549,7 +548,7 @@ fn waitpid(pid: pid_t) -> int {
             INFINITE,
             WAIT_FAILED
         };
-        use libc::funcs::extra::kernel32::{
+        use std::libc::funcs::extra::kernel32::{
             OpenProcess,
             GetExitCodeProcess,
             CloseHandle,
@@ -585,7 +584,7 @@ fn waitpid(pid: pid_t) -> int {
 
     #[cfg(unix)]
     fn waitpid_os(pid: pid_t) -> int {
-        use libc::funcs::posix01::wait::*;
+        use std::libc::funcs::posix01::wait;
 
         #[cfg(target_os = "linux")]
         #[cfg(target_os = "android")]
@@ -612,7 +611,7 @@ fn waitpid(pid: pid_t) -> int {
         }
 
         let mut status = 0 as c_int;
-        if unsafe { waitpid(pid, &mut status, 0) } == -1 {
+        if unsafe { wait::waitpid(pid, &mut status, 0) } == -1 {
             fail!("failure in waitpid: {}", os::last_os_error());
         }
 
diff --git a/src/libnative/lib.rs b/src/libnative/lib.rs
new file mode 100644
index 00000000000..e0666592651
--- /dev/null
+++ b/src/libnative/lib.rs
@@ -0,0 +1,94 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The native runtime crate
+//!
+//! This crate contains an implementation of 1:1 scheduling for a "native"
+//! runtime. In addition, all I/O provided by this crate is the thread blocking
+//! version of I/O.
+
+#[pkgid = "native#0.9-pre"];
+#[crate_id = "native#0.9-pre"];
+#[license = "MIT/ASL2"];
+#[crate_type = "rlib"];
+#[crate_type = "dylib"];
+
+// Allow check-stage0-native for now
+#[cfg(stage0, test)] extern mod green;
+
+// NB this crate explicitly does *not* allow glob imports, please seriously
+//    consider whether they're needed before adding that feature here (the
+//    answer is that you don't need them)
+
+use std::os;
+use std::rt::local::Local;
+use std::rt::task::Task;
+use std::rt;
+
+pub mod io;
+pub mod task;
+
+
+// XXX: this should not exist here
+#[cfg(stage0)]
+#[lang = "start"]
+pub fn lang_start(main: *u8, argc: int, argv: **u8) -> int {
+    use std::cast;
+    use std::task;
+
+    do start(argc, argv) {
+        // Instead of invoking main directly on this thread, invoke it on
+        // another spawned thread that we are guaranteed to know the size of the
+        // stack of. Currently, we do not have a method of figuring out the size
+        // of the main thread's stack, so for stack overflow detection to work
+        // we must spawn the task in a subtask which we know the stack size of.
+        let main: extern "Rust" fn() = unsafe { cast::transmute(main) };
+        let mut task = task::task();
+        task.name("<main>");
+        match do task.try { main() } {
+            Ok(()) => { os::set_exit_status(0); }
+            Err(..) => { os::set_exit_status(rt::DEFAULT_ERROR_CODE); }
+        }
+    }
+}
+
+/// Executes the given procedure after initializing the runtime with the given
+/// argc/argv.
+///
+/// This procedure is guaranteed to run on the thread calling this function, but
+/// the stack bounds for this rust task will *not* be set. Care must be taken
+/// for this function to not overflow its stack.
+///
+/// This function will only return once *all* native threads in the system have
+/// exited.
+pub fn start(argc: int, argv: **u8, main: proc()) -> int {
+    rt::init(argc, argv);
+    let mut exit_code = None;
+    let mut main = Some(main);
+    task::new().run(|| {
+        exit_code = Some(run(main.take_unwrap()));
+    });
+    unsafe { rt::cleanup(); }
+    return exit_code.unwrap();
+}
+
+/// Executes a procedure on the current thread in a Rust task context.
+///
+/// This function has all of the same details as `start` except for a different
+/// number of arguments.
+pub fn run(main: proc()) -> int {
+    // Run the main procedure and then wait for everything to finish
+    main();
+    unsafe {
+        let mut task = Local::borrow(None::<Task>);
+        task.get().wait_for_other_tasks();
+    }
+    os::get_exit_status()
+}
diff --git a/src/libnative/task.rs b/src/libnative/task.rs
new file mode 100644
index 00000000000..12e361d8041
--- /dev/null
+++ b/src/libnative/task.rs
@@ -0,0 +1,330 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Tasks implemented on top of OS threads
+//!
+//! This module contains the implementation of the 1:1 threading module required
+//! by rust tasks. This implements the necessary API traits laid out by std::rt
+//! in order to spawn new tasks and deschedule the current task.
+
+use std::cast;
+use std::rt::env;
+use std::rt::local::Local;
+use std::rt::rtio;
+use std::rt::task::{Task, BlockedTask};
+use std::rt::thread::Thread;
+use std::rt;
+use std::task::TaskOpts;
+use std::unstable::mutex::Mutex;
+use std::unstable::stack;
+
+use io;
+use task;
+
+/// Creates a new Task which is ready to execute as a 1:1 task.
+pub fn new() -> ~Task {
+    let mut task = ~Task::new();
+    task.put_runtime(~Ops {
+        lock: unsafe { Mutex::new() },
+        awoken: false,
+    } as ~rt::Runtime);
+    return task;
+}
+
+/// Spawns a function with the default configuration
+pub fn spawn(f: proc()) {
+    spawn_opts(TaskOpts::new(), f)
+}
+
+/// Spawns a new task given the configuration options and a procedure to run
+/// inside the task.
+pub fn spawn_opts(opts: TaskOpts, f: proc()) {
+    let TaskOpts {
+        watched: _watched,
+        notify_chan, name, stack_size
+    } = opts;
+
+    let mut task = new();
+    task.name = name;
+    match notify_chan {
+        Some(chan) => {
+            let on_exit = proc(task_result) { chan.send(task_result) };
+            task.death.on_exit = Some(on_exit);
+        }
+        None => {}
+    }
+
+    let stack = stack_size.unwrap_or(env::min_stack());
+    let task = task;
+
+    // Spawning a new OS thread guarantees that __morestack will never get
+    // triggered, but we must manually set up the actual stack bounds once this
+    // function starts executing. This raises the lower limit by a bit because
+    // by the time that this function is executing we've already consumed at
+    // least a little bit of stack (we don't know the exact byte address at
+    // which our stack started).
+    Thread::spawn_stack(stack, proc() {
+        let something_around_the_top_of_the_stack = 1;
+        let addr = &something_around_the_top_of_the_stack as *int;
+        unsafe {
+            let my_stack = addr as uint;
+            stack::record_stack_bounds(my_stack - stack + 1024, my_stack);
+        }
+
+        let mut f = Some(f);
+        task.run(|| { f.take_unwrap()() });
+    })
+}
+
+// This structure is the glue between channels and the 1:1 scheduling mode. This
+// structure is allocated once per task.
+struct Ops {
+    lock: Mutex,  // native synchronization
+    awoken: bool, // used to prevent spurious wakeups
+}
+
+impl rt::Runtime for Ops {
+    fn yield_now(~self, mut cur_task: ~Task) {
+        // put the task back in TLS and then invoke the OS thread yield
+        cur_task.put_runtime(self as ~rt::Runtime);
+        Local::put(cur_task);
+        Thread::yield_now();
+    }
+
+    fn maybe_yield(~self, mut cur_task: ~Task) {
+        // just put the task back in TLS, on OS threads we never need to
+        // opportunistically yield b/c the OS will do that for us (preemption)
+        cur_task.put_runtime(self as ~rt::Runtime);
+        Local::put(cur_task);
+    }
+
+    fn wrap(~self) -> ~Any {
+        self as ~Any
+    }
+
+    // This function gets a little interesting. There are a few safety and
+    // ownership violations going on here, but this is all done in the name of
+    // shared state. Additionally, all of the violations are protected with a
+    // mutex, so in theory there are no races.
+    //
+    // The first thing we need to do is to get a pointer to the task's internal
+    // mutex. This address will not be changing (because the task is allocated
+    // on the heap). We must have this handle separately because the task will
+    // have its ownership transferred to the given closure. We're guaranteed,
+    // however, that this memory will remain valid because *this* is the current
+    // task's execution thread.
+    //
+    // The next weird part is where ownership of the task actually goes. We
+    // relinquish it to the `f` blocking function, but upon returning this
+    // function needs to replace the task back in TLS. There is no communication
+    // from the wakeup thread back to this thread about the task pointer, and
+    // there's really no need to. In order to get around this, we cast the task
+    // to a `uint` which is then used at the end of this function to cast back
+    // to a `~Task` object. Naturally, this looks like it violates ownership
+    // semantics in that there may be two `~Task` objects.
+    //
+    // The fun part is that the wakeup half of this implementation knows to
+    // "forget" the task on the other end. This means that the awakening half of
+    // things silently relinquishes ownership back to this thread, but not in a
+    // way that the compiler can understand. The task's memory is always valid
+    // for both tasks because these operations are all done inside of a mutex.
+    //
+    // You'll also find that if blocking fails (the `f` function hands the
+    // BlockedTask back to us), we will `cast::forget` the handles. The
+    // reasoning for this is the same logic as above in that the task silently
+    // transfers ownership via the `uint`, not through normal compiler
+    // semantics.
+    //
+    // On a mildly unrelated note, it should also be pointed out that OS
+    // condition variables are susceptible to spurious wakeups, which we need to
+    // be ready for. In order to accomodate for this fact, we have an extra
+    // `awoken` field which indicates whether we were actually woken up via some
+    // invocation of `reawaken`. This flag is only ever accessed inside the
+    // lock, so there's no need to make it atomic.
+    fn deschedule(mut ~self, times: uint, mut cur_task: ~Task,
+                  f: |BlockedTask| -> Result<(), BlockedTask>) {
+        let me = &mut *self as *mut Ops;
+        cur_task.put_runtime(self as ~rt::Runtime);
+
+        unsafe {
+            let cur_task_dupe = *cast::transmute::<&~Task, &uint>(&cur_task);
+            let task = BlockedTask::block(cur_task);
+
+            if times == 1 {
+                (*me).lock.lock();
+                (*me).awoken = false;
+                match f(task) {
+                    Ok(()) => {
+                        while !(*me).awoken {
+                            (*me).lock.wait();
+                        }
+                    }
+                    Err(task) => { cast::forget(task.wake()); }
+                }
+                (*me).lock.unlock();
+            } else {
+                let mut iter = task.make_selectable(times);
+                (*me).lock.lock();
+                (*me).awoken = false;
+                let success = iter.all(|task| {
+                    match f(task) {
+                        Ok(()) => true,
+                        Err(task) => {
+                            cast::forget(task.wake());
+                            false
+                        }
+                    }
+                });
+                while success && !(*me).awoken {
+                    (*me).lock.wait();
+                }
+                (*me).lock.unlock();
+            }
+            // re-acquire ownership of the task
+            cur_task = cast::transmute::<uint, ~Task>(cur_task_dupe);
+        }
+
+        // put the task back in TLS, and everything is as it once was.
+        Local::put(cur_task);
+    }
+
+    // See the comments on `deschedule` for why the task is forgotten here, and
+    // why it's valid to do so.
+    fn reawaken(mut ~self, mut to_wake: ~Task, _can_resched: bool) {
+        unsafe {
+            let me = &mut *self as *mut Ops;
+            to_wake.put_runtime(self as ~rt::Runtime);
+            cast::forget(to_wake);
+            (*me).lock.lock();
+            (*me).awoken = true;
+            (*me).lock.signal();
+            (*me).lock.unlock();
+        }
+    }
+
+    fn spawn_sibling(~self, mut cur_task: ~Task, opts: TaskOpts, f: proc()) {
+        cur_task.put_runtime(self as ~rt::Runtime);
+        Local::put(cur_task);
+
+        task::spawn_opts(opts, f);
+    }
+
+    fn local_io<'a>(&'a mut self) -> Option<rtio::LocalIo<'a>> {
+        static mut io: io::IoFactory = io::IoFactory;
+        // Unsafety is from accessing `io`, which is guaranteed to be safe
+        // because you can't do anything usable with this statically initialized
+        // unit struct.
+        Some(unsafe { rtio::LocalIo::new(&mut io as &mut rtio::IoFactory) })
+    }
+}
+
+impl Drop for Ops {
+    fn drop(&mut self) {
+        unsafe { self.lock.destroy() }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::rt::Runtime;
+    use std::rt::local::Local;
+    use std::rt::task::Task;
+    use std::task;
+    use std::task::TaskOpts;
+    use super::{spawn, spawn_opts, Ops};
+
+    #[test]
+    fn smoke() {
+        let (p, c) = Chan::new();
+        do spawn {
+            c.send(());
+        }
+        p.recv();
+    }
+
+    #[test]
+    fn smoke_fail() {
+        let (p, c) = Chan::<()>::new();
+        do spawn {
+            let _c = c;
+            fail!()
+        }
+        assert_eq!(p.recv_opt(), None);
+    }
+
+    #[test]
+    fn smoke_opts() {
+        let mut opts = TaskOpts::new();
+        opts.name = Some(SendStrStatic("test"));
+        opts.stack_size = Some(20 * 4096);
+        let (p, c) = Chan::new();
+        opts.notify_chan = Some(c);
+        spawn_opts(opts, proc() {});
+        assert!(p.recv().is_ok());
+    }
+
+    #[test]
+    fn smoke_opts_fail() {
+        let mut opts = TaskOpts::new();
+        let (p, c) = Chan::new();
+        opts.notify_chan = Some(c);
+        spawn_opts(opts, proc() { fail!() });
+        assert!(p.recv().is_err());
+    }
+
+    #[test]
+    fn yield_test() {
+        let (p, c) = Chan::new();
+        do spawn {
+            10.times(task::deschedule);
+            c.send(());
+        }
+        p.recv();
+    }
+
+    #[test]
+    fn spawn_children() {
+        let (p, c) = Chan::new();
+        do spawn {
+            let (p, c2) = Chan::new();
+            do spawn {
+                let (p, c3) = Chan::new();
+                do spawn {
+                    c3.send(());
+                }
+                p.recv();
+                c2.send(());
+            }
+            p.recv();
+            c.send(());
+        }
+        p.recv();
+    }
+
+    #[test]
+    fn spawn_inherits() {
+        let (p, c) = Chan::new();
+        do spawn {
+            let c = c;
+            do spawn {
+                let mut task: ~Task = Local::take();
+                match task.maybe_take_runtime::<Ops>() {
+                    Some(ops) => {
+                        task.put_runtime(ops as ~Runtime);
+                    }
+                    None => fail!(),
+                }
+                Local::put(task);
+                c.send(());
+            }
+        }
+        p.recv();
+    }
+}
diff --git a/src/librustc/back/link.rs b/src/librustc/back/link.rs
index 37114660826..11a63db6aba 100644
--- a/src/librustc/back/link.rs
+++ b/src/librustc/back/link.rs
@@ -333,6 +333,10 @@ pub mod write {
     }
 
     unsafe fn configure_llvm(sess: Session) {
+        use std::unstable::mutex::{MUTEX_INIT, Mutex};
+        static mut LOCK: Mutex = MUTEX_INIT;
+        static mut CONFIGURED: bool = false;
+
         // Copy what clan does by turning on loop vectorization at O2 and
         // slp vectorization at O3
         let vectorize_loop = !sess.no_vectorize_loops() &&
@@ -360,7 +364,13 @@ pub mod write {
             add(*arg);
         }
 
-        llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int, llvm_args.as_ptr());
+        LOCK.lock();
+        if !CONFIGURED {
+            llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
+                                         llvm_args.as_ptr());
+            CONFIGURED = true;
+        }
+        LOCK.unlock();
     }
 
     unsafe fn populate_llvm_passes(fpm: lib::llvm::PassManagerRef,
diff --git a/src/librustc/front/std_inject.rs b/src/librustc/front/std_inject.rs
index a40f8183e19..1503e4effeb 100644
--- a/src/librustc/front/std_inject.rs
+++ b/src/librustc/front/std_inject.rs
@@ -70,6 +70,15 @@ impl fold::ast_fold for StandardLibraryInjector {
         }];
 
         if use_uv(&crate) && !*self.sess.building_library {
+            vis.push(ast::view_item {
+                node: ast::view_item_extern_mod(self.sess.ident_of("green"),
+                                                None,
+                                                ~[vers_item],
+                                                ast::DUMMY_NODE_ID),
+                attrs: ~[],
+                vis: ast::private,
+                span: dummy_sp()
+            });
             vis.push(ast::view_item {
                 node: ast::view_item_extern_mod(self.sess.ident_of("rustuv"),
                                                 None,
diff --git a/src/librustc/middle/trans/debuginfo.rs b/src/librustc/middle/trans/debuginfo.rs
index a77e8f764f3..61fadb7e236 100644
--- a/src/librustc/middle/trans/debuginfo.rs
+++ b/src/librustc/middle/trans/debuginfo.rs
@@ -146,7 +146,7 @@ use std::hashmap::HashMap;
 use std::hashmap::HashSet;
 use std::libc::{c_uint, c_ulonglong, c_longlong};
 use std::ptr;
-use std::unstable::atomics;
+use std::sync::atomics;
 use std::vec;
 use syntax::codemap::{Span, Pos};
 use syntax::{ast, codemap, ast_util, ast_map, opt_vec};
diff --git a/src/librustpkg/path_util.rs b/src/librustpkg/path_util.rs
index a6b1088335c..0d927fc36ae 100644
--- a/src/librustpkg/path_util.rs
+++ b/src/librustpkg/path_util.rs
@@ -390,7 +390,7 @@ pub fn mk_output_path(what: OutputType, where: Target,
                                Bench => "bench",
                                _     => ""
                            },
-                           os::EXE_SUFFIX))
+                           os::consts::EXE_SUFFIX))
     };
     if !output_path.is_absolute() {
         output_path = os::getcwd().join(&output_path);
diff --git a/src/librustpkg/tests.rs b/src/librustpkg/tests.rs
index ecf08df5f18..21f18eda140 100644
--- a/src/librustpkg/tests.rs
+++ b/src/librustpkg/tests.rs
@@ -487,8 +487,9 @@ fn lib_output_file_name(workspace: &Path, short_name: &str) -> Path {
 }
 
 fn output_file_name(workspace: &Path, short_name: ~str) -> Path {
-    target_build_dir(workspace).join(short_name.as_slice()).join(format!("{}{}", short_name,
-                                                                         os::EXE_SUFFIX))
+    target_build_dir(workspace).join(short_name.as_slice())
+                               .join(format!("{}{}", short_name,
+                                             os::consts::EXE_SUFFIX))
 }
 
 #[cfg(target_os = "linux")]
@@ -1353,7 +1354,7 @@ fn test_import_rustpkg() {
     command_line_test([~"build", ~"foo"], workspace);
     debug!("workspace = {}", workspace.display());
     assert!(target_build_dir(workspace).join("foo").join(format!("pkg{}",
-        os::EXE_SUFFIX)).exists());
+        os::consts::EXE_SUFFIX)).exists());
 }
 
 #[test]
@@ -1366,7 +1367,7 @@ fn test_macro_pkg_script() {
     command_line_test([~"build", ~"foo"], workspace);
     debug!("workspace = {}", workspace.display());
     assert!(target_build_dir(workspace).join("foo").join(format!("pkg{}",
-        os::EXE_SUFFIX)).exists());
+        os::consts::EXE_SUFFIX)).exists());
 }
 
 #[test]
diff --git a/src/librustuv/addrinfo.rs b/src/librustuv/addrinfo.rs
index 04c1c5a9fb8..f6fad524b5c 100644
--- a/src/librustuv/addrinfo.rs
+++ b/src/librustuv/addrinfo.rs
@@ -11,12 +11,10 @@
 use ai = std::io::net::addrinfo;
 use std::libc::c_int;
 use std::ptr::null;
-use std::rt::BlockedTask;
-use std::rt::local::Local;
-use std::rt::sched::Scheduler;
+use std::rt::task::BlockedTask;
 
 use net;
-use super::{Loop, UvError, Request, wait_until_woken_after};
+use super::{Loop, UvError, Request, wait_until_woken_after, wakeup};
 use uvll;
 
 struct Addrinfo {
@@ -108,8 +106,7 @@ impl GetAddrInfoRequest {
             cx.status = status;
             cx.addrinfo = Some(Addrinfo { handle: res });
 
-            let sched: ~Scheduler = Local::take();
-            sched.resume_blocked_task_immediately(cx.slot.take_unwrap());
+            wakeup(&mut cx.slot);
         }
     }
 }
@@ -188,12 +185,13 @@ pub fn accum_addrinfo(addr: &Addrinfo) -> ~[ai::Info] {
 #[cfg(test, not(target_os="android"))]
 mod test {
     use std::io::net::ip::{SocketAddr, Ipv4Addr};
-    use super::*;
     use super::super::local_loop;
+    use super::GetAddrInfoRequest;
 
     #[test]
     fn getaddrinfo_test() {
-        match GetAddrInfoRequest::run(local_loop(), Some("localhost"), None, None) {
+        let loop_ = &mut local_loop().loop_;
+        match GetAddrInfoRequest::run(loop_, Some("localhost"), None, None) {
             Ok(infos) => {
                 let mut found_local = false;
                 let local_addr = &SocketAddr {
@@ -211,9 +209,10 @@ mod test {
 
     #[test]
     fn issue_10663() {
+        let loop_ = &mut local_loop().loop_;
         // Something should happen here, but this certainly shouldn't cause
         // everything to die. The actual outcome we don't care too much about.
-        GetAddrInfoRequest::run(local_loop(), Some("irc.n0v4.com"), None,
+        GetAddrInfoRequest::run(loop_, Some("irc.n0v4.com"), None,
                                 None);
     }
 }
diff --git a/src/librustuv/async.rs b/src/librustuv/async.rs
index 5a0db8313fb..0c353785982 100644
--- a/src/librustuv/async.rs
+++ b/src/librustuv/async.rs
@@ -127,16 +127,15 @@ impl Drop for AsyncWatcher {
 mod test_remote {
     use std::rt::rtio::Callback;
     use std::rt::thread::Thread;
-    use std::rt::tube::Tube;
 
-    use super::*;
+    use super::AsyncWatcher;
     use super::super::local_loop;
 
     // Make sure that we can fire watchers in remote threads and that they
     // actually trigger what they say they will.
     #[test]
     fn smoke_test() {
-        struct MyCallback(Option<Tube<int>>);
+        struct MyCallback(Option<Chan<int>>);
         impl Callback for MyCallback {
             fn call(&mut self) {
                 // this can get called more than once, but we only want to send
@@ -147,16 +146,17 @@ mod test_remote {
             }
         }
 
-        let mut tube = Tube::new();
-        let cb = ~MyCallback(Some(tube.clone()));
-        let watcher = AsyncWatcher::new(local_loop(), cb as ~Callback);
+        let (port, chan) = Chan::new();
+        let cb = ~MyCallback(Some(chan));
+        let watcher = AsyncWatcher::new(&mut local_loop().loop_,
+                                        cb as ~Callback);
 
         let thread = do Thread::start {
             let mut watcher = watcher;
             watcher.fire();
         };
 
-        assert_eq!(tube.recv(), 1);
+        assert_eq!(port.recv(), 1);
         thread.join();
     }
 }
diff --git a/src/librustuv/file.rs b/src/librustuv/file.rs
index 3a8af71e019..82d0fd823a3 100644
--- a/src/librustuv/file.rs
+++ b/src/librustuv/file.rs
@@ -14,15 +14,14 @@ use std::cast::transmute;
 use std::cast;
 use std::libc::{c_int, c_char, c_void, size_t};
 use std::libc;
-use std::rt::BlockedTask;
+use std::rt::task::BlockedTask;
 use std::io::{FileStat, IoError};
 use std::io;
-use std::rt::local::Local;
 use std::rt::rtio;
-use std::rt::sched::{Scheduler, SchedHandle};
 
-use super::{Loop, UvError, uv_error_to_io_error, wait_until_woken_after};
-use uvio::HomingIO;
+use homing::{HomingIO, HomeHandle};
+use super::{Loop, UvError, uv_error_to_io_error, wait_until_woken_after, wakeup};
+use uvio::UvIoFactory;
 use uvll;
 
 pub struct FsRequest {
@@ -34,19 +33,19 @@ pub struct FileWatcher {
     priv loop_: Loop,
     priv fd: c_int,
     priv close: rtio::CloseBehavior,
-    priv home: SchedHandle,
+    priv home: HomeHandle,
 }
 
 impl FsRequest {
-    pub fn open(loop_: &Loop, path: &CString, flags: int, mode: int)
+    pub fn open(io: &mut UvIoFactory, path: &CString, flags: int, mode: int)
         -> Result<FileWatcher, UvError>
     {
         execute(|req, cb| unsafe {
-            uvll::uv_fs_open(loop_.handle,
+            uvll::uv_fs_open(io.uv_loop(),
                              req, path.with_ref(|p| p), flags as c_int,
                              mode as c_int, cb)
         }).map(|req|
-            FileWatcher::new(*loop_, req.get_result() as c_int,
+            FileWatcher::new(io, req.get_result() as c_int,
                              rtio::CloseSynchronously)
         )
     }
@@ -320,8 +319,7 @@ fn execute(f: |*uvll::uv_fs_t, uvll::uv_fs_cb| -> c_int)
         let slot: &mut Option<BlockedTask> = unsafe {
             cast::transmute(uvll::get_data_for_req(req))
         };
-        let sched: ~Scheduler = Local::take();
-        sched.resume_blocked_task_immediately(slot.take_unwrap());
+        wakeup(slot);
     }
 }
 
@@ -331,16 +329,17 @@ fn execute_nop(f: |*uvll::uv_fs_t, uvll::uv_fs_cb| -> c_int)
 }
 
 impl HomingIO for FileWatcher {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl FileWatcher {
-    pub fn new(loop_: Loop, fd: c_int, close: rtio::CloseBehavior) -> FileWatcher {
+    pub fn new(io: &mut UvIoFactory, fd: c_int,
+               close: rtio::CloseBehavior) -> FileWatcher {
         FileWatcher {
-            loop_: loop_,
+            loop_: Loop::wrap(io.uv_loop()),
             fd: fd,
             close: close,
-            home: get_handle_to_current_scheduler!()
+            home: io.make_handle(),
         }
     }
 
@@ -448,8 +447,11 @@ mod test {
     use std::io;
     use std::str;
     use std::vec;
-    use super::*;
-    use l = super::super::local_loop;
+    use super::FsRequest;
+    use super::super::Loop;
+    use super::super::local_loop;
+
+    fn l() -> &mut Loop { &mut local_loop().loop_ }
 
     #[test]
     fn file_test_full_simple_sync() {
@@ -460,7 +462,7 @@ mod test {
 
         {
             // open/create
-            let result = FsRequest::open(l(), &path_str.to_c_str(),
+            let result = FsRequest::open(local_loop(), &path_str.to_c_str(),
                                          create_flags as int, mode as int);
             assert!(result.is_ok());
             let result = result.unwrap();
@@ -473,7 +475,7 @@ mod test {
 
         {
             // re-open
-            let result = FsRequest::open(l(), &path_str.to_c_str(),
+            let result = FsRequest::open(local_loop(), &path_str.to_c_str(),
                                          read_flags as int, 0);
             assert!(result.is_ok());
             let result = result.unwrap();
@@ -500,7 +502,7 @@ mod test {
         let create_flags = (O_RDWR | O_CREAT) as int;
         let mode = (S_IWUSR | S_IRUSR) as int;
 
-        let result = FsRequest::open(l(), path, create_flags, mode);
+        let result = FsRequest::open(local_loop(), path, create_flags, mode);
         assert!(result.is_ok());
         let file = result.unwrap();
 
diff --git a/src/librustuv/homing.rs b/src/librustuv/homing.rs
new file mode 100644
index 00000000000..16534b7b38b
--- /dev/null
+++ b/src/librustuv/homing.rs
@@ -0,0 +1,212 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Homing I/O implementation
+//!
+//! In libuv, whenever a handle is created on an I/O loop it is illegal to use
+//! that handle outside of that I/O loop. We use libuv I/O with our green
+//! scheduler, and each green scheduler corresponds to a different I/O loop on a
+//! different OS thread. Green tasks are also free to roam among schedulers,
+//! which implies that it is possible to create an I/O handle on one event loop
+//! and then attempt to use it on another.
+//!
+//! In order to solve this problem, this module implements the notion of a
+//! "homing operation" which will transplant a task from its currently running
+//! scheduler back onto the original I/O loop. This is accomplished entirely at
+//! the librustuv layer with very little cooperation from the scheduler (which
+//! we don't even know exists technically).
+//!
+//! These homing operations are completed by first realizing that we're on the
+//! wrong I/O loop, then descheduling ourselves, sending ourselves to the
+//! correct I/O loop, and then waking up the I/O loop in order to process its
+//! local queue of tasks which need to run.
+//!
+//! This enqueueing is done with a concurrent queue from libstd, and the
+//! signalling is achieved with an async handle.
+
+#[allow(dead_code)];
+
+use std::cast;
+use std::rt::local::Local;
+use std::rt::rtio::LocalIo;
+use std::rt::task::{Task, BlockedTask};
+
+use ForbidUnwind;
+use queue::{Queue, QueuePool};
+
+/// A handle to a remote libuv event loop. This handle will keep the event loop
+/// alive while active in order to ensure that a homing operation can always be
+/// completed.
+///
+/// Handles are clone-able in order to derive new handles from existing handles
+/// (very useful for when accepting a socket from a server).
+pub struct HomeHandle {
+    priv queue: Queue,
+    priv id: uint,
+}
+
+impl HomeHandle {
+    pub fn new(id: uint, pool: &mut QueuePool) -> HomeHandle {
+        HomeHandle { queue: pool.queue(), id: id }
+    }
+
+    fn send(&mut self, task: BlockedTask) {
+        self.queue.push(task);
+    }
+}
+
+impl Clone for HomeHandle {
+    fn clone(&self) -> HomeHandle {
+        HomeHandle {
+            queue: self.queue.clone(),
+            id: self.id,
+        }
+    }
+}
+
+pub fn local_id() -> uint {
+    let mut io = match LocalIo::borrow() {
+        Some(io) => io, None => return 0,
+    };
+    let io = io.get();
+    unsafe {
+        let (_vtable, ptr): (uint, uint) = cast::transmute(io);
+        return ptr;
+    }
+}
+
+pub trait HomingIO {
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle;
+
+    /// This function will move tasks to run on their home I/O scheduler. Note
+    /// that this function does *not* pin the task to the I/O scheduler, but
+    /// rather it simply moves it to running on the I/O scheduler.
+    fn go_to_IO_home(&mut self) -> uint {
+        let _f = ForbidUnwind::new("going home");
+
+        let cur_loop_id = local_id();
+        let destination = self.home().id;
+
+        // Try at all costs to avoid the homing operation because it is quite
+        // expensive. Hence, we only deschedule/send if we're not on the correct
+        // event loop. If we're already on the home event loop, then we're good
+        // to go (remember we have no preemption, so we're guaranteed to stay on
+        // this event loop as long as we avoid the scheduler).
+        if cur_loop_id != destination {
+            let cur_task: ~Task = Local::take();
+            cur_task.deschedule(1, |task| {
+                self.home().send(task);
+                Ok(())
+            });
+
+            // Once we wake up, assert that we're in the right location
+            assert_eq!(local_id(), destination);
+        }
+
+        return destination;
+    }
+
+    /// Fires a single homing missile, returning another missile targeted back
+    /// at the original home of this task. In other words, this function will
+    /// move the local task to its I/O scheduler and then return an RAII wrapper
+    /// which will return the task home.
+    fn fire_homing_missile(&mut self) -> HomingMissile {
+        HomingMissile { io_home: self.go_to_IO_home() }
+    }
+}
+
+/// After a homing operation has been completed, this will return the current
+/// task back to its appropriate home (if applicable). The field is used to
+/// assert that we are where we think we are.
+struct HomingMissile {
+    priv io_home: uint,
+}
+
+impl HomingMissile {
+    /// Check at runtime that the task has *not* transplanted itself to a
+    /// different I/O loop while executing.
+    pub fn check(&self, msg: &'static str) {
+        assert!(local_id() == self.io_home, "{}", msg);
+    }
+}
+
+impl Drop for HomingMissile {
+    fn drop(&mut self) {
+        let _f = ForbidUnwind::new("leaving home");
+
+        // It would truly be a sad day if we had moved off the home I/O
+        // scheduler while we were doing I/O.
+        self.check("task moved away from the home scheduler");
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use green::sched;
+    use green::{SchedPool, PoolConfig};
+    use std::rt::rtio::RtioUdpSocket;
+    use std::io::test::next_test_ip4;
+    use std::task::TaskOpts;
+
+    use net::UdpWatcher;
+    use super::super::local_loop;
+
+    // On one thread, create a udp socket. Then send that socket to another
+    // thread and destroy the socket on the remote thread. This should make sure
+    // that homing kicks in for the socket to go back home to the original
+    // thread, close itself, and then come back to the last thread.
+    #[test]
+    fn test_homing_closes_correctly() {
+        let (port, chan) = Chan::new();
+        let mut pool = SchedPool::new(PoolConfig {
+            threads: 1,
+            event_loop_factory: None,
+        });
+
+        do pool.spawn(TaskOpts::new()) {
+            let listener = UdpWatcher::bind(local_loop(), next_test_ip4());
+            chan.send(listener.unwrap());
+        }
+
+        let task = do pool.task(TaskOpts::new()) {
+            port.recv();
+        };
+        pool.spawn_sched().send(sched::TaskFromFriend(task));
+
+        pool.shutdown();
+    }
+
+    #[test]
+    fn test_homing_read() {
+        let (port, chan) = Chan::new();
+        let mut pool = SchedPool::new(PoolConfig {
+            threads: 1,
+            event_loop_factory: None,
+        });
+
+        do pool.spawn(TaskOpts::new()) {
+            let addr1 = next_test_ip4();
+            let addr2 = next_test_ip4();
+            let listener = UdpWatcher::bind(local_loop(), addr2);
+            chan.send((listener.unwrap(), addr1));
+            let mut listener = UdpWatcher::bind(local_loop(), addr1).unwrap();
+            listener.sendto([1, 2, 3, 4], addr2);
+        }
+
+        let task = do pool.task(TaskOpts::new()) {
+            let (mut watcher, addr) = port.recv();
+            let mut buf = [0, ..10];
+            assert_eq!(watcher.recvfrom(buf).unwrap(), (4, addr));
+        };
+        pool.spawn_sched().send(sched::TaskFromFriend(task));
+
+        pool.shutdown();
+    }
+}
diff --git a/src/librustuv/idle.rs b/src/librustuv/idle.rs
index 32c7699a308..80d21404e4b 100644
--- a/src/librustuv/idle.rs
+++ b/src/librustuv/idle.rs
@@ -97,72 +97,102 @@ impl Drop for IdleWatcher {
 
 #[cfg(test)]
 mod test {
-    use super::*;
-    use std::rt::tube::Tube;
+    use std::cast;
+    use std::cell::RefCell;
+    use std::rc::Rc;
     use std::rt::rtio::{Callback, PausableIdleCallback};
+    use std::rt::task::{BlockedTask, Task};
+    use std::rt::local::Local;
+    use super::IdleWatcher;
     use super::super::local_loop;
 
-    struct MyCallback(Tube<int>, int);
+    type Chan = Rc<RefCell<(Option<BlockedTask>, uint)>>;
+
+    struct MyCallback(Rc<RefCell<(Option<BlockedTask>, uint)>>, uint);
     impl Callback for MyCallback {
         fn call(&mut self) {
-            match *self {
-                MyCallback(ref mut tube, val) => tube.send(val)
-            }
+            let task = match *self {
+                MyCallback(ref rc, n) => {
+                    let mut slot = rc.borrow().borrow_mut();
+                    match *slot.get() {
+                        (ref mut task, ref mut val) => {
+                            *val = n;
+                            task.take_unwrap()
+                        }
+                    }
+                }
+            };
+            task.wake().map(|t| t.reawaken(true));
         }
     }
 
+    fn mk(v: uint) -> (~IdleWatcher, Chan) {
+        let rc = Rc::from_send(RefCell::new((None, 0)));
+        let cb = ~MyCallback(rc.clone(), v);
+        let cb = cb as ~Callback:;
+        let cb = unsafe { cast::transmute(cb) };
+        (IdleWatcher::new(&mut local_loop().loop_, cb), rc)
+    }
+
+    fn sleep(chan: &Chan) -> uint {
+        let task: ~Task = Local::take();
+        task.deschedule(1, |task| {
+            let mut slot = chan.borrow().borrow_mut();
+            match *slot.get() {
+                (ref mut slot, _) => {
+                    assert!(slot.is_none());
+                    *slot = Some(task);
+                }
+            }
+            Ok(())
+        });
+
+        let slot = chan.borrow().borrow();
+        match *slot.get() { (_, n) => n }
+    }
+
     #[test]
     fn not_used() {
-        let cb = ~MyCallback(Tube::new(), 1);
-        let _idle = IdleWatcher::new(local_loop(), cb as ~Callback);
+        let (_idle, _chan) = mk(1);
     }
 
     #[test]
     fn smoke_test() {
-        let mut tube = Tube::new();
-        let cb = ~MyCallback(tube.clone(), 1);
-        let mut idle = IdleWatcher::new(local_loop(), cb as ~Callback);
+        let (mut idle, chan) = mk(1);
         idle.resume();
-        tube.recv();
+        assert_eq!(sleep(&chan), 1);
     }
 
     #[test] #[should_fail]
     fn smoke_fail() {
-        let tube = Tube::new();
-        let cb = ~MyCallback(tube.clone(), 1);
-        let mut idle = IdleWatcher::new(local_loop(), cb as ~Callback);
+        let (mut idle, _chan) = mk(1);
         idle.resume();
         fail!();
     }
 
     #[test]
     fn fun_combinations_of_methods() {
-        let mut tube = Tube::new();
-        let cb = ~MyCallback(tube.clone(), 1);
-        let mut idle = IdleWatcher::new(local_loop(), cb as ~Callback);
+        let (mut idle, chan) = mk(1);
         idle.resume();
-        tube.recv();
+        assert_eq!(sleep(&chan), 1);
         idle.pause();
         idle.resume();
         idle.resume();
-        tube.recv();
+        assert_eq!(sleep(&chan), 1);
         idle.pause();
         idle.pause();
         idle.resume();
-        tube.recv();
+        assert_eq!(sleep(&chan), 1);
     }
 
     #[test]
     fn pause_pauses() {
-        let mut tube = Tube::new();
-        let cb = ~MyCallback(tube.clone(), 1);
-        let mut idle1 = IdleWatcher::new(local_loop(), cb as ~Callback);
-        let cb = ~MyCallback(tube.clone(), 2);
-        let mut idle2 = IdleWatcher::new(local_loop(), cb as ~Callback);
+        let (mut idle1, chan1) = mk(1);
+        let (mut idle2, chan2) = mk(2);
         idle2.resume();
-        assert_eq!(tube.recv(), 2);
+        assert_eq!(sleep(&chan2), 2);
         idle2.pause();
         idle1.resume();
-        assert_eq!(tube.recv(), 1);
+        assert_eq!(sleep(&chan1), 1);
     }
 }
diff --git a/src/librustuv/lib.rs b/src/librustuv/lib.rs
index 2e5b7254769..2ef10dd33ac 100644
--- a/src/librustuv/lib.rs
+++ b/src/librustuv/lib.rs
@@ -41,23 +41,23 @@ via `close` and `delete` methods.
 #[crate_type = "rlib"];
 #[crate_type = "dylib"];
 
-#[feature(macro_rules, globs)];
+#[feature(macro_rules)];
+
+#[cfg(test)] extern mod green;
 
-use std::cast::transmute;
 use std::cast;
+use std::io;
+use std::io::IoError;
 use std::libc::{c_int, malloc};
 use std::ptr::null;
 use std::ptr;
-use std::rt::BlockedTask;
 use std::rt::local::Local;
-use std::rt::sched::Scheduler;
+use std::rt::task::{BlockedTask, Task};
 use std::str::raw::from_c_str;
 use std::str;
 use std::task;
 use std::unstable::finally::Finally;
 
-use std::io::IoError;
-
 pub use self::async::AsyncWatcher;
 pub use self::file::{FsRequest, FileWatcher};
 pub use self::idle::IdleWatcher;
@@ -70,6 +70,9 @@ pub use self::tty::TtyWatcher;
 
 mod macros;
 
+mod queue;
+mod homing;
+
 /// The implementation of `rtio` for libuv
 pub mod uvio;
 
@@ -144,32 +147,29 @@ pub trait UvHandle<T> {
                 uvll::free_handle(handle);
                 if data == ptr::null() { return }
                 let slot: &mut Option<BlockedTask> = cast::transmute(data);
-                let sched: ~Scheduler = Local::take();
-                sched.resume_blocked_task_immediately(slot.take_unwrap());
+                wakeup(slot);
             }
         }
     }
 }
 
 pub struct ForbidSwitch {
-    msg: &'static str,
-    sched: uint,
+    priv msg: &'static str,
+    priv io: uint,
 }
 
 impl ForbidSwitch {
     fn new(s: &'static str) -> ForbidSwitch {
-        let mut sched = Local::borrow(None::<Scheduler>);
         ForbidSwitch {
             msg: s,
-            sched: sched.get().sched_id(),
+            io: homing::local_id(),
         }
     }
 }
 
 impl Drop for ForbidSwitch {
     fn drop(&mut self) {
-        let mut sched = Local::borrow(None::<Scheduler>);
-        assert!(self.sched == sched.get().sched_id(),
+        assert!(self.io == homing::local_id(),
                 "didnt want a scheduler switch: {}",
                 self.msg);
     }
@@ -199,14 +199,20 @@ fn wait_until_woken_after(slot: *mut Option<BlockedTask>, f: ||) {
     let _f = ForbidUnwind::new("wait_until_woken_after");
     unsafe {
         assert!((*slot).is_none());
-        let sched: ~Scheduler = Local::take();
-        sched.deschedule_running_task_and_then(|_, task| {
-            f();
+        let task: ~Task = Local::take();
+        task.deschedule(1, |task| {
             *slot = Some(task);
-        })
+            f();
+            Ok(())
+        });
     }
 }
 
+fn wakeup(slot: &mut Option<BlockedTask>) {
+    assert!(slot.is_some());
+    slot.take_unwrap().wake().map(|t| t.reawaken(true));
+}
+
 pub struct Request {
     handle: *uvll::uv_req_t,
     priv defused: bool,
@@ -325,28 +331,26 @@ fn error_smoke_test() {
 pub fn uv_error_to_io_error(uverr: UvError) -> IoError {
     unsafe {
         // Importing error constants
-        use uvll::*;
-        use std::io::*;
 
         // uv error descriptions are static
         let c_desc = uvll::uv_strerror(*uverr);
         let desc = str::raw::c_str_to_static_slice(c_desc);
 
         let kind = match *uverr {
-            UNKNOWN => OtherIoError,
-            OK => OtherIoError,
-            EOF => EndOfFile,
-            EACCES => PermissionDenied,
-            ECONNREFUSED => ConnectionRefused,
-            ECONNRESET => ConnectionReset,
-            ENOENT => FileNotFound,
-            ENOTCONN => NotConnected,
-            EPIPE => BrokenPipe,
-            ECONNABORTED => ConnectionAborted,
+            uvll::UNKNOWN => io::OtherIoError,
+            uvll::OK => io::OtherIoError,
+            uvll::EOF => io::EndOfFile,
+            uvll::EACCES => io::PermissionDenied,
+            uvll::ECONNREFUSED => io::ConnectionRefused,
+            uvll::ECONNRESET => io::ConnectionReset,
+            uvll::ENOTCONN => io::NotConnected,
+            uvll::ENOENT => io::FileNotFound,
+            uvll::EPIPE => io::BrokenPipe,
+            uvll::ECONNABORTED => io::ConnectionAborted,
             err => {
                 uvdebug!("uverr.code {}", err as int);
                 // XXX: Need to map remaining uv error types
-                OtherIoError
+                io::OtherIoError
             }
         };
 
@@ -387,15 +391,17 @@ pub fn slice_to_uv_buf(v: &[u8]) -> Buf {
     uvll::uv_buf_t { base: data, len: v.len() as uvll::uv_buf_len_t }
 }
 
+// This function is full of lies!
 #[cfg(test)]
-fn local_loop() -> &'static mut Loop {
+fn local_loop() -> &'static mut uvio::UvIoFactory {
     unsafe {
         cast::transmute({
-            let mut sched = Local::borrow(None::<Scheduler>);
+            let mut task = Local::borrow(None::<Task>);
+            let mut io = task.get().local_io().unwrap();
             let (_vtable, uvio): (uint, &'static mut uvio::UvIoFactory) =
-                cast::transmute(sched.get().event_loop.io().unwrap());
+                cast::transmute(io.get());
             uvio
-        }.uv_loop())
+        })
     }
 }
 
diff --git a/src/librustuv/macros.rs b/src/librustuv/macros.rs
index a63dcc6de31..6c8c16784a1 100644
--- a/src/librustuv/macros.rs
+++ b/src/librustuv/macros.rs
@@ -27,18 +27,20 @@ macro_rules! uvdebug (
     })
 )
 
-// get a handle for the current scheduler
-macro_rules! get_handle_to_current_scheduler(
-    () => ({
-        let mut sched = Local::borrow(None::<Scheduler>);
-        sched.get().make_handle()
-    })
-)
-
 pub fn dumb_println(args: &fmt::Arguments) {
-    use std::io::native::file::FileDesc;
     use std::io;
     use std::libc;
-    let mut out = FileDesc::new(libc::STDERR_FILENO, false);
-    fmt::writeln(&mut out as &mut io::Writer, args);
+
+    struct Stderr;
+    impl io::Writer for Stderr {
+        fn write(&mut self, data: &[u8]) {
+            unsafe {
+                libc::write(libc::STDERR_FILENO,
+                            data.as_ptr() as *libc::c_void,
+                            data.len() as libc::size_t);
+            }
+        }
+    }
+    let mut w = Stderr;
+    fmt::writeln(&mut w as &mut io::Writer, args);
 }
diff --git a/src/librustuv/net.rs b/src/librustuv/net.rs
index ce543eafd2f..85e9202c1fa 100644
--- a/src/librustuv/net.rs
+++ b/src/librustuv/net.rs
@@ -9,24 +9,22 @@
 // except according to those terms.
 
 use std::cast;
-use std::libc;
-use std::libc::{size_t, ssize_t, c_int, c_void, c_uint, c_char};
-use std::ptr;
-use std::rt::BlockedTask;
 use std::io::IoError;
 use std::io::net::ip::{Ipv4Addr, Ipv6Addr, SocketAddr, IpAddr};
-use std::rt::local::Local;
+use std::libc::{size_t, ssize_t, c_int, c_void, c_uint, c_char};
+use std::libc;
+use std::ptr;
 use std::rt::rtio;
-use std::rt::sched::{Scheduler, SchedHandle};
-use std::rt::tube::Tube;
+use std::rt::task::BlockedTask;
 use std::str;
 use std::vec;
 
+use homing::{HomingIO, HomeHandle};
 use stream::StreamWatcher;
 use super::{Loop, Request, UvError, Buf, status_to_io_result,
             uv_error_to_io_error, UvHandle, slice_to_uv_buf,
-            wait_until_woken_after};
-use uvio::HomingIO;
+            wait_until_woken_after, wakeup};
+use uvio::UvIoFactory;
 use uvll;
 use uvll::sockaddr;
 
@@ -88,21 +86,19 @@ pub fn sockaddr_to_socket_addr(addr: *sockaddr) -> SocketAddr {
     }
 }
 
-#[cfg(test)]
 #[test]
 fn test_ip4_conversion() {
-    use std::rt;
-    let ip4 = rt::test::next_test_ip4();
+    use std::io::net::ip::{SocketAddr, Ipv4Addr};
+    let ip4 = SocketAddr { ip: Ipv4Addr(127, 0, 0, 1), port: 4824 };
     socket_addr_as_sockaddr(ip4, |addr| {
         assert_eq!(ip4, sockaddr_to_socket_addr(addr));
     })
 }
 
-#[cfg(test)]
 #[test]
 fn test_ip6_conversion() {
-    use std::rt;
-    let ip6 = rt::test::next_test_ip6();
+    use std::io::net::ip::{SocketAddr, Ipv6Addr};
+    let ip6 = SocketAddr { ip: Ipv6Addr(0, 0, 0, 0, 0, 0, 0, 1), port: 4824 };
     socket_addr_as_sockaddr(ip6, |addr| {
         assert_eq!(ip6, sockaddr_to_socket_addr(addr));
     })
@@ -145,42 +141,47 @@ fn socket_name(sk: SocketNameKind, handle: *c_void) -> Result<SocketAddr, IoErro
 pub struct TcpWatcher {
     handle: *uvll::uv_tcp_t,
     stream: StreamWatcher,
-    home: SchedHandle,
+    home: HomeHandle,
 }
 
 pub struct TcpListener {
-    home: SchedHandle,
+    home: HomeHandle,
     handle: *uvll::uv_pipe_t,
     priv closing_task: Option<BlockedTask>,
-    priv outgoing: Tube<Result<~rtio::RtioTcpStream, IoError>>,
+    priv outgoing: Chan<Result<~rtio::RtioTcpStream, IoError>>,
+    priv incoming: Port<Result<~rtio::RtioTcpStream, IoError>>,
 }
 
 pub struct TcpAcceptor {
     listener: ~TcpListener,
-    priv incoming: Tube<Result<~rtio::RtioTcpStream, IoError>>,
 }
 
 // TCP watchers (clients/streams)
 
 impl TcpWatcher {
-    pub fn new(loop_: &Loop) -> TcpWatcher {
+    pub fn new(io: &mut UvIoFactory) -> TcpWatcher {
+        let handle = io.make_handle();
+        TcpWatcher::new_home(&io.loop_, handle)
+    }
+
+    fn new_home(loop_: &Loop, home: HomeHandle) -> TcpWatcher {
         let handle = unsafe { uvll::malloc_handle(uvll::UV_TCP) };
         assert_eq!(unsafe {
             uvll::uv_tcp_init(loop_.handle, handle)
         }, 0);
         TcpWatcher {
-            home: get_handle_to_current_scheduler!(),
+            home: home,
             handle: handle,
             stream: StreamWatcher::new(handle),
         }
     }
 
-    pub fn connect(loop_: &mut Loop, address: SocketAddr)
+    pub fn connect(io: &mut UvIoFactory, address: SocketAddr)
         -> Result<TcpWatcher, UvError>
     {
         struct Ctx { status: c_int, task: Option<BlockedTask> }
 
-        let tcp = TcpWatcher::new(loop_);
+        let tcp = TcpWatcher::new(io);
         let ret = socket_addr_as_sockaddr(address, |addr| {
             let mut req = Request::new(uvll::UV_CONNECT);
             let result = unsafe {
@@ -213,14 +214,13 @@ impl TcpWatcher {
             assert!(status != uvll::ECANCELED);
             let cx: &mut Ctx = unsafe { req.get_data() };
             cx.status = status;
-            let scheduler: ~Scheduler = Local::take();
-            scheduler.resume_blocked_task_immediately(cx.task.take_unwrap());
+            wakeup(&mut cx.task);
         }
     }
 }
 
 impl HomingIO for TcpWatcher {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl rtio::RtioSocket for TcpWatcher {
@@ -290,17 +290,19 @@ impl Drop for TcpWatcher {
 // TCP listeners (unbound servers)
 
 impl TcpListener {
-    pub fn bind(loop_: &mut Loop, address: SocketAddr)
+    pub fn bind(io: &mut UvIoFactory, address: SocketAddr)
                 -> Result<~TcpListener, UvError> {
         let handle = unsafe { uvll::malloc_handle(uvll::UV_TCP) };
         assert_eq!(unsafe {
-            uvll::uv_tcp_init(loop_.handle, handle)
+            uvll::uv_tcp_init(io.uv_loop(), handle)
         }, 0);
+        let (port, chan) = Chan::new();
         let l = ~TcpListener {
-            home: get_handle_to_current_scheduler!(),
+            home: io.make_handle(),
             handle: handle,
             closing_task: None,
-            outgoing: Tube::new(),
+            outgoing: chan,
+            incoming: port,
         };
         let res = socket_addr_as_sockaddr(address, |addr| unsafe {
             uvll::uv_tcp_bind(l.handle, addr)
@@ -313,7 +315,7 @@ impl TcpListener {
 }
 
 impl HomingIO for TcpListener {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl UvHandle<uvll::uv_tcp_t> for TcpListener {
@@ -330,11 +332,7 @@ impl rtio::RtioSocket for TcpListener {
 impl rtio::RtioTcpListener for TcpListener {
     fn listen(mut ~self) -> Result<~rtio::RtioTcpAcceptor, IoError> {
         // create the acceptor object from ourselves
-        let incoming = self.outgoing.clone();
-        let mut acceptor = ~TcpAcceptor {
-            listener: self,
-            incoming: incoming,
-        };
+        let mut acceptor = ~TcpAcceptor { listener: self };
 
         let _m = acceptor.fire_homing_missile();
         // XXX: the 128 backlog should be configurable
@@ -347,19 +345,18 @@ impl rtio::RtioTcpListener for TcpListener {
 
 extern fn listen_cb(server: *uvll::uv_stream_t, status: c_int) {
     assert!(status != uvll::ECANCELED);
+    let tcp: &mut TcpListener = unsafe { UvHandle::from_uv_handle(&server) };
     let msg = match status {
         0 => {
             let loop_ = Loop::wrap(unsafe {
                 uvll::get_loop_for_uv_handle(server)
             });
-            let client = TcpWatcher::new(&loop_);
+            let client = TcpWatcher::new_home(&loop_, tcp.home().clone());
             assert_eq!(unsafe { uvll::uv_accept(server, client.handle) }, 0);
             Ok(~client as ~rtio::RtioTcpStream)
         }
         n => Err(uv_error_to_io_error(UvError(n)))
     };
-
-    let tcp: &mut TcpListener = unsafe { UvHandle::from_uv_handle(&server) };
     tcp.outgoing.send(msg);
 }
 
@@ -373,7 +370,7 @@ impl Drop for TcpListener {
 // TCP acceptors (bound servers)
 
 impl HomingIO for TcpAcceptor {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { self.listener.home() }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { self.listener.home() }
 }
 
 impl rtio::RtioSocket for TcpAcceptor {
@@ -385,8 +382,7 @@ impl rtio::RtioSocket for TcpAcceptor {
 
 impl rtio::RtioTcpAcceptor for TcpAcceptor {
     fn accept(&mut self) -> Result<~rtio::RtioTcpStream, IoError> {
-        let _m = self.fire_homing_missile();
-        self.incoming.recv()
+        self.listener.incoming.recv()
     }
 
     fn accept_simultaneously(&mut self) -> Result<(), IoError> {
@@ -410,18 +406,18 @@ impl rtio::RtioTcpAcceptor for TcpAcceptor {
 
 pub struct UdpWatcher {
     handle: *uvll::uv_udp_t,
-    home: SchedHandle,
+    home: HomeHandle,
 }
 
 impl UdpWatcher {
-    pub fn bind(loop_: &Loop, address: SocketAddr)
+    pub fn bind(io: &mut UvIoFactory, address: SocketAddr)
                 -> Result<UdpWatcher, UvError> {
         let udp = UdpWatcher {
             handle: unsafe { uvll::malloc_handle(uvll::UV_UDP) },
-            home: get_handle_to_current_scheduler!(),
+            home: io.make_handle(),
         };
         assert_eq!(unsafe {
-            uvll::uv_udp_init(loop_.handle, udp.handle)
+            uvll::uv_udp_init(io.uv_loop(), udp.handle)
         }, 0);
         let result = socket_addr_as_sockaddr(address, |addr| unsafe {
             uvll::uv_udp_bind(udp.handle, addr, 0u32)
@@ -438,7 +434,7 @@ impl UvHandle<uvll::uv_udp_t> for UdpWatcher {
 }
 
 impl HomingIO for UdpWatcher {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl rtio::RtioSocket for UdpWatcher {
@@ -519,9 +515,7 @@ impl rtio::RtioUdpSocket for UdpWatcher {
                 Some(sockaddr_to_socket_addr(addr))
             };
             cx.result = Some((nread, addr));
-
-            let sched: ~Scheduler = Local::take();
-            sched.resume_blocked_task_immediately(cx.task.take_unwrap());
+            wakeup(&mut cx.task);
         }
     }
 
@@ -556,9 +550,7 @@ impl rtio::RtioUdpSocket for UdpWatcher {
             assert!(status != uvll::ECANCELED);
             let cx: &mut Ctx = unsafe { req.get_data() };
             cx.result = status;
-
-            let sched: ~Scheduler = Local::take();
-            sched.resume_blocked_task_immediately(cx.task.take_unwrap());
+            wakeup(&mut cx.task);
         }
     }
 
@@ -640,18 +632,13 @@ impl Drop for UdpWatcher {
     }
 }
 
-////////////////////////////////////////////////////////////////////////////////
-/// UV request support
-////////////////////////////////////////////////////////////////////////////////
-
 #[cfg(test)]
 mod test {
-    use std::rt::test::*;
     use std::rt::rtio::{RtioTcpStream, RtioTcpListener, RtioTcpAcceptor,
                         RtioUdpSocket};
-    use std::task;
+    use std::io::test::{next_test_ip4, next_test_ip6};
 
-    use super::*;
+    use super::{UdpWatcher, TcpWatcher, TcpListener};
     use super::super::local_loop;
 
     #[test]
@@ -824,7 +811,6 @@ mod test {
 
     #[test]
     fn test_read_read_read() {
-        use std::rt::rtio::*;
         let addr = next_test_ip4();
         static MAX: uint = 5000;
         let (port, chan) = Chan::new();
@@ -843,20 +829,18 @@ mod test {
             }
         }
 
-        do spawn {
-            port.recv();
-            let mut stream = TcpWatcher::connect(local_loop(), addr).unwrap();
-            let mut buf = [0, .. 2048];
-            let mut total_bytes_read = 0;
-            while total_bytes_read < MAX {
-                let nread = stream.read(buf).unwrap();
-                total_bytes_read += nread;
-                for i in range(0u, nread) {
-                    assert_eq!(buf[i], 1);
-                }
+        port.recv();
+        let mut stream = TcpWatcher::connect(local_loop(), addr).unwrap();
+        let mut buf = [0, .. 2048];
+        let mut total_bytes_read = 0;
+        while total_bytes_read < MAX {
+            let nread = stream.read(buf).unwrap();
+            total_bytes_read += nread;
+            for i in range(0u, nread) {
+                assert_eq!(buf[i], 1);
             }
-            uvdebug!("read {} bytes total", total_bytes_read);
         }
+        uvdebug!("read {} bytes total", total_bytes_read);
     }
 
     #[test]
@@ -922,65 +906,35 @@ mod test {
             assert!(total_bytes_sent >= MAX);
         }
 
-        do spawn {
-            let l = local_loop();
-            let mut client_out = UdpWatcher::bind(l, client_out_addr).unwrap();
-            let mut client_in = UdpWatcher::bind(l, client_in_addr).unwrap();
-            let (port, chan) = (p2, c1);
-            port.recv();
-            chan.send(());
-            let mut total_bytes_recv = 0;
-            let mut buf = [0, .. 2048];
-            while total_bytes_recv < MAX {
-                // ask for more
-                assert!(client_out.sendto([1], server_in_addr).is_ok());
-                // wait for data
-                let res = client_in.recvfrom(buf);
-                assert!(res.is_ok());
-                let (nread, src) = res.unwrap();
-                assert_eq!(src, server_out_addr);
-                total_bytes_recv += nread;
-                for i in range(0u, nread) {
-                    assert_eq!(buf[i], 1);
-                }
+        let l = local_loop();
+        let mut client_out = UdpWatcher::bind(l, client_out_addr).unwrap();
+        let mut client_in = UdpWatcher::bind(l, client_in_addr).unwrap();
+        let (port, chan) = (p2, c1);
+        port.recv();
+        chan.send(());
+        let mut total_bytes_recv = 0;
+        let mut buf = [0, .. 2048];
+        while total_bytes_recv < MAX {
+            // ask for more
+            assert!(client_out.sendto([1], server_in_addr).is_ok());
+            // wait for data
+            let res = client_in.recvfrom(buf);
+            assert!(res.is_ok());
+            let (nread, src) = res.unwrap();
+            assert_eq!(src, server_out_addr);
+            total_bytes_recv += nread;
+            for i in range(0u, nread) {
+                assert_eq!(buf[i], 1);
             }
-            // tell the server we're done
-            assert!(client_out.sendto([0], server_in_addr).is_ok());
         }
+        // tell the server we're done
+        assert!(client_out.sendto([0], server_in_addr).is_ok());
     }
 
     #[test]
     fn test_read_and_block() {
         let addr = next_test_ip4();
-        let (port, chan) = Chan::new();
-
-        do spawn {
-            let listener = TcpListener::bind(local_loop(), addr).unwrap();
-            let mut acceptor = listener.listen().unwrap();
-            let (port2, chan2) = Chan::new();
-            chan.send(port2);
-            let mut stream = acceptor.accept().unwrap();
-            let mut buf = [0, .. 2048];
-
-            let expected = 32;
-            let mut current = 0;
-            let mut reads = 0;
-
-            while current < expected {
-                let nread = stream.read(buf).unwrap();
-                for i in range(0u, nread) {
-                    let val = buf[i] as uint;
-                    assert_eq!(val, current % 8);
-                    current += 1;
-                }
-                reads += 1;
-
-                chan2.send(());
-            }
-
-            // Make sure we had multiple reads
-            assert!(reads > 1);
-        }
+        let (port, chan) = Chan::<Port<()>>::new();
 
         do spawn {
             let port2 = port.recv();
@@ -992,13 +946,39 @@ mod test {
             stream.write([0, 1, 2, 3, 4, 5, 6, 7]);
             port2.recv();
         }
+
+        let listener = TcpListener::bind(local_loop(), addr).unwrap();
+        let mut acceptor = listener.listen().unwrap();
+        let (port2, chan2) = Chan::new();
+        chan.send(port2);
+        let mut stream = acceptor.accept().unwrap();
+        let mut buf = [0, .. 2048];
+
+        let expected = 32;
+        let mut current = 0;
+        let mut reads = 0;
+
+        while current < expected {
+            let nread = stream.read(buf).unwrap();
+            for i in range(0u, nread) {
+                let val = buf[i] as uint;
+                assert_eq!(val, current % 8);
+                current += 1;
+            }
+            reads += 1;
+
+            chan2.try_send(());
+        }
+
+        // Make sure we had multiple reads
+        assert!(reads > 1);
     }
 
     #[test]
     fn test_simple_tcp_server_and_client_on_diff_threads() {
         let addr = next_test_ip4();
 
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             let listener = TcpListener::bind(local_loop(), addr).unwrap();
             let mut acceptor = listener.listen().unwrap();
             let mut stream = acceptor.accept().unwrap();
@@ -1010,131 +990,11 @@ mod test {
             }
         }
 
-        do task::spawn_sched(task::SingleThreaded) {
-            let mut stream = TcpWatcher::connect(local_loop(), addr);
-            while stream.is_err() {
-                stream = TcpWatcher::connect(local_loop(), addr);
-            }
-            stream.unwrap().write([0, 1, 2, 3, 4, 5, 6, 7]);
-        }
-    }
-
-    // On one thread, create a udp socket. Then send that socket to another
-    // thread and destroy the socket on the remote thread. This should make sure
-    // that homing kicks in for the socket to go back home to the original
-    // thread, close itself, and then come back to the last thread.
-    #[test]
-    fn test_homing_closes_correctly() {
-        let (port, chan) = Chan::new();
-
-        do task::spawn_sched(task::SingleThreaded) {
-            let listener = UdpWatcher::bind(local_loop(), next_test_ip4()).unwrap();
-            chan.send(listener);
-        }
-
-        do task::spawn_sched(task::SingleThreaded) {
-            port.recv();
-        }
-    }
-
-    // This is a bit of a crufty old test, but it has its uses.
-    #[test]
-    fn test_simple_homed_udp_io_bind_then_move_task_then_home_and_close() {
-        use std::cast;
-        use std::rt::local::Local;
-        use std::rt::rtio::{EventLoop, IoFactory};
-        use std::rt::sched::Scheduler;
-        use std::rt::sched::{Shutdown, TaskFromFriend};
-        use std::rt::sleeper_list::SleeperList;
-        use std::rt::task::Task;
-        use std::rt::thread::Thread;
-        use std::rt::deque::BufferPool;
-        use std::task::TaskResult;
-        use std::unstable::run_in_bare_thread;
-        use uvio::UvEventLoop;
-
-        do run_in_bare_thread {
-            let sleepers = SleeperList::new();
-            let mut pool = BufferPool::new();
-            let (worker1, stealer1) = pool.deque();
-            let (worker2, stealer2) = pool.deque();
-            let queues = ~[stealer1, stealer2];
-
-            let loop1 = ~UvEventLoop::new() as ~EventLoop;
-            let mut sched1 = ~Scheduler::new(loop1, worker1, queues.clone(),
-                                             sleepers.clone());
-            let loop2 = ~UvEventLoop::new() as ~EventLoop;
-            let mut sched2 = ~Scheduler::new(loop2, worker2, queues.clone(),
-                                             sleepers.clone());
-
-            let handle1 = sched1.make_handle();
-            let handle2 = sched2.make_handle();
-            let tasksFriendHandle = sched2.make_handle();
-
-            let on_exit: proc(TaskResult) = proc(exit_status) {
-                let mut handle1 = handle1;
-                let mut handle2 = handle2;
-                handle1.send(Shutdown);
-                handle2.send(Shutdown);
-                assert!(exit_status.is_ok());
-            };
-
-            unsafe fn local_io() -> &'static mut IoFactory {
-                let mut sched = Local::borrow(None::<Scheduler>);
-                let io = sched.get().event_loop.io();
-                cast::transmute(io.unwrap())
-            }
-
-            let test_function: proc() = proc() {
-                let io = unsafe { local_io() };
-                let addr = next_test_ip4();
-                let maybe_socket = io.udp_bind(addr);
-                // this socket is bound to this event loop
-                assert!(maybe_socket.is_ok());
-
-                // block self on sched1
-                let scheduler: ~Scheduler = Local::take();
-                let mut tasksFriendHandle = Some(tasksFriendHandle);
-                scheduler.deschedule_running_task_and_then(|_, task| {
-                    // unblock task
-                    task.wake().map(|task| {
-                        // send self to sched2
-                        tasksFriendHandle.take_unwrap()
-                                         .send(TaskFromFriend(task));
-                    });
-                    // sched1 should now sleep since it has nothing else to do
-                })
-                // sched2 will wake up and get the task as we do nothing else,
-                // the function ends and the socket goes out of scope sched2
-                // will start to run the destructor the destructor will first
-                // block the task, set it's home as sched1, then enqueue it
-                // sched2 will dequeue the task, see that it has a home, and
-                // send it to sched1 sched1 will wake up, exec the close
-                // function on the correct loop, and then we're done
-            };
-
-            let mut main_task = ~Task::new_root(&mut sched1.stack_pool, None,
-                                                test_function);
-            main_task.death.on_exit = Some(on_exit);
-
-            let null_task = ~do Task::new_root(&mut sched2.stack_pool, None) {
-                // nothing
-            };
-
-            let main_task = main_task;
-            let sched1 = sched1;
-            let thread1 = do Thread::start {
-                sched1.bootstrap(main_task);
-            };
-
-            let sched2 = sched2;
-            let thread2 = do Thread::start {
-                sched2.bootstrap(null_task);
-            };
-
-            thread1.join();
-            thread2.join();
+        let mut stream = TcpWatcher::connect(local_loop(), addr);
+        while stream.is_err() {
+            stream = TcpWatcher::connect(local_loop(), addr);
         }
+        stream.unwrap().write([0, 1, 2, 3, 4, 5, 6, 7]);
     }
 
     #[should_fail] #[test]
@@ -1176,7 +1036,7 @@ mod test {
         // force the handle to be created on a different scheduler, failure in
         // the original task will force a homing operation back to this
         // scheduler.
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             let w = UdpWatcher::bind(local_loop(), addr).unwrap();
             chan.send(w);
         }
@@ -1184,67 +1044,4 @@ mod test {
         let _w = port.recv();
         fail!();
     }
-
-    #[should_fail]
-    #[test]
-    #[ignore(reason = "linked failure")]
-    fn linked_failure1() {
-        let (port, chan) = Chan::new();
-        let addr = next_test_ip4();
-
-        do spawn {
-            let w = TcpListener::bind(local_loop(), addr).unwrap();
-            let mut w = w.listen().unwrap();
-            chan.send(());
-            w.accept();
-        }
-
-        port.recv();
-        fail!();
-    }
-
-    #[should_fail]
-    #[test]
-    #[ignore(reason = "linked failure")]
-    fn linked_failure2() {
-        let (port, chan) = Chan::new();
-        let addr = next_test_ip4();
-
-        do spawn {
-            let w = TcpListener::bind(local_loop(), addr).unwrap();
-            let mut w = w.listen().unwrap();
-            chan.send(());
-            let mut buf = [0];
-            w.accept().unwrap().read(buf);
-        }
-
-        port.recv();
-        let _w = TcpWatcher::connect(local_loop(), addr).unwrap();
-
-        fail!();
-    }
-
-    #[should_fail]
-    #[test]
-    #[ignore(reason = "linked failure")]
-    fn linked_failure3() {
-        let (port, chan) = Chan::new();
-        let addr = next_test_ip4();
-
-        do spawn {
-            let chan = chan;
-            let w = TcpListener::bind(local_loop(), addr).unwrap();
-            let mut w = w.listen().unwrap();
-            chan.send(());
-            let mut conn = w.accept().unwrap();
-            chan.send(());
-            let buf = [0, ..65536];
-            conn.write(buf);
-        }
-
-        port.recv();
-        let _w = TcpWatcher::connect(local_loop(), addr).unwrap();
-        port.recv();
-        fail!();
-    }
 }
diff --git a/src/librustuv/pipe.rs b/src/librustuv/pipe.rs
index 814205cbbf1..ff4481e8b97 100644
--- a/src/librustuv/pipe.rs
+++ b/src/librustuv/pipe.rs
@@ -9,35 +9,33 @@
 // except according to those terms.
 
 use std::c_str::CString;
-use std::libc;
-use std::rt::BlockedTask;
 use std::io::IoError;
-use std::rt::local::Local;
+use std::libc;
 use std::rt::rtio::{RtioPipe, RtioUnixListener, RtioUnixAcceptor};
-use std::rt::sched::{Scheduler, SchedHandle};
-use std::rt::tube::Tube;
+use std::rt::task::BlockedTask;
 
+use homing::{HomingIO, HomeHandle};
 use stream::StreamWatcher;
 use super::{Loop, UvError, UvHandle, Request, uv_error_to_io_error,
-            wait_until_woken_after};
-use uvio::HomingIO;
+            wait_until_woken_after, wakeup};
+use uvio::UvIoFactory;
 use uvll;
 
 pub struct PipeWatcher {
     stream: StreamWatcher,
-    home: SchedHandle,
+    home: HomeHandle,
     priv defused: bool,
 }
 
 pub struct PipeListener {
-    home: SchedHandle,
+    home: HomeHandle,
     pipe: *uvll::uv_pipe_t,
-    priv outgoing: Tube<Result<~RtioPipe, IoError>>,
+    priv outgoing: Chan<Result<~RtioPipe, IoError>>,
+    priv incoming: Port<Result<~RtioPipe, IoError>>,
 }
 
 pub struct PipeAcceptor {
     listener: ~PipeListener,
-    priv incoming: Tube<Result<~RtioPipe, IoError>>,
 }
 
 // PipeWatcher implementation and traits
@@ -46,7 +44,12 @@ impl PipeWatcher {
     // Creates an uninitialized pipe watcher. The underlying uv pipe is ready to
     // get bound to some other source (this is normally a helper method paired
     // with another call).
-    pub fn new(loop_: &Loop, ipc: bool) -> PipeWatcher {
+    pub fn new(io: &mut UvIoFactory, ipc: bool) -> PipeWatcher {
+        let home = io.make_handle();
+        PipeWatcher::new_home(&io.loop_, home, ipc)
+    }
+
+    pub fn new_home(loop_: &Loop, home: HomeHandle, ipc: bool) -> PipeWatcher {
         let handle = unsafe {
             let handle = uvll::malloc_handle(uvll::UV_NAMED_PIPE);
             assert!(!handle.is_null());
@@ -56,26 +59,28 @@ impl PipeWatcher {
         };
         PipeWatcher {
             stream: StreamWatcher::new(handle),
-            home: get_handle_to_current_scheduler!(),
+            home: home,
             defused: false,
         }
     }
 
-    pub fn open(loop_: &Loop, file: libc::c_int) -> Result<PipeWatcher, UvError>
+    pub fn open(io: &mut UvIoFactory, file: libc::c_int)
+        -> Result<PipeWatcher, UvError>
     {
-        let pipe = PipeWatcher::new(loop_, false);
+        let pipe = PipeWatcher::new(io, false);
         match unsafe { uvll::uv_pipe_open(pipe.handle(), file) } {
             0 => Ok(pipe),
             n => Err(UvError(n))
         }
     }
 
-    pub fn connect(loop_: &Loop, name: &CString) -> Result<PipeWatcher, UvError>
+    pub fn connect(io: &mut UvIoFactory, name: &CString)
+        -> Result<PipeWatcher, UvError>
     {
         struct Ctx { task: Option<BlockedTask>, result: libc::c_int, }
         let mut cx = Ctx { task: None, result: 0 };
         let mut req = Request::new(uvll::UV_CONNECT);
-        let pipe = PipeWatcher::new(loop_, false);
+        let pipe = PipeWatcher::new(io, false);
 
         wait_until_woken_after(&mut cx.task, || {
             unsafe {
@@ -97,8 +102,7 @@ impl PipeWatcher {
             assert!(status != uvll::ECANCELED);
             let cx: &mut Ctx = unsafe { req.get_data() };
             cx.result = status;
-            let sched: ~Scheduler = Local::take();
-            sched.resume_blocked_task_immediately(cx.task.take_unwrap());
+            wakeup(&mut cx.task);
         }
     }
 
@@ -125,7 +129,7 @@ impl RtioPipe for PipeWatcher {
 }
 
 impl HomingIO for PipeWatcher {
-    fn home<'a>(&'a mut self) -> &'a mut SchedHandle { &mut self.home }
+    fn home<'a>(&'a mut self) -> &'a mut HomeHandle { &mut self.home }
 }
 
 impl UvHandle<uvll::uv_pipe_t> for PipeWatcher {
@@ -144,8 +148,10 @@ impl Drop for PipeWatcher {
 // PipeListener implementation and traits
 
 impl PipeListener {
-    pub fn bind(loop_: &Loop, name: &CString) -> Result<~PipeListener, UvError> {
-        let pipe = PipeWatcher::new(loop_, false);
+    pub fn bind(io: &mut UvIoFactory, name: &CString)
+        -> Result<~PipeListener, UvError>
+    {
+        let pipe = PipeWatcher::new(io, false);
         match unsafe {
             uvll::uv_pipe_bind(pipe.handle(), name.with_ref(|p| p))
         } {
@@ -153,10 +159,12 @@ impl PipeListener {
                 // If successful, unwrap the PipeWatcher because we control how
                 // we close the pipe differently. We can't rely on
                 // StreamWatcher's default close method.
+                let (port, chan) = Chan::new();
                 let p = ~PipeListener {
-                    home: get_handle_to_current_scheduler!(),
+                    home: io.make_handle(),
                     pipe: pipe.unwrap(),
-                    outgoing: Tube::new(),
+                    incoming: port,
+                    outgoing: chan,
                 };
                 Ok(p.install())
             }
@@ -168,11 +176,7 @@ impl PipeListener {
 impl RtioUnixListener for PipeListener {
     fn listen(mut ~self) -> Result<~RtioUnixAcceptor, IoError> {
         // create the acceptor object from ourselves
-        let incoming = self.outgoing.clone();
-        let mut acceptor = ~PipeAcceptor {
-            listener: self,
-            incoming: incoming,
-        };
+        let mut acceptor = ~PipeAcceptor { listener: self };
 
         let _m = acceptor.fire_homing_missile();
         // XXX: the 128 backlog should be configurable
@@ -184,7 +188,7 @@ impl RtioUnixListener for PipeListener {
 }
 
 impl HomingIO for PipeListener {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl UvHandle<uvll::uv_pipe_t> for PipeListener {
@@ -193,19 +197,19 @@ impl UvHandle<uvll::uv_pipe_t> for PipeListener {
 
 extern fn listen_cb(server: *uvll::uv_stream_t, status: libc::c_int) {
     assert!(status != uvll::ECANCELED);
+
+    let pipe: &mut PipeListener = unsafe { UvHandle::from_uv_handle(&server) };
     let msg = match status {
         0 => {
             let loop_ = Loop::wrap(unsafe {
                 uvll::get_loop_for_uv_handle(server)
             });
-            let client = PipeWatcher::new(&loop_, false);
+            let client = PipeWatcher::new_home(&loop_, pipe.home().clone(), false);
             assert_eq!(unsafe { uvll::uv_accept(server, client.handle()) }, 0);
             Ok(~client as ~RtioPipe)
         }
         n => Err(uv_error_to_io_error(UvError(n)))
     };
-
-    let pipe: &mut PipeListener = unsafe { UvHandle::from_uv_handle(&server) };
     pipe.outgoing.send(msg);
 }
 
@@ -220,21 +224,20 @@ impl Drop for PipeListener {
 
 impl RtioUnixAcceptor for PipeAcceptor {
     fn accept(&mut self) -> Result<~RtioPipe, IoError> {
-        let _m = self.fire_homing_missile();
-        self.incoming.recv()
+        self.listener.incoming.recv()
     }
 }
 
 impl HomingIO for PipeAcceptor {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { self.listener.home() }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.listener.home }
 }
 
 #[cfg(test)]
 mod tests {
     use std::rt::rtio::{RtioUnixListener, RtioUnixAcceptor, RtioPipe};
-    use std::rt::test::next_test_unix;
+    use std::io::test::next_test_unix;
 
-    use super::*;
+    use super::{PipeWatcher, PipeListener};
     use super::super::local_loop;
 
     #[test]
diff --git a/src/librustuv/process.rs b/src/librustuv/process.rs
index 9e359e26f03..7b7a16d7084 100644
--- a/src/librustuv/process.rs
+++ b/src/librustuv/process.rs
@@ -8,32 +8,31 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::io::IoError;
+use std::io::process;
 use std::libc::c_int;
 use std::libc;
 use std::ptr;
-use std::rt::BlockedTask;
-use std::io::IoError;
-use std::io::process::*;
-use std::rt::local::Local;
 use std::rt::rtio::RtioProcess;
-use std::rt::sched::{Scheduler, SchedHandle};
+use std::rt::task::BlockedTask;
 use std::vec;
 
-use super::{Loop, UvHandle, UvError, uv_error_to_io_error,
-            wait_until_woken_after};
-use uvio::HomingIO;
-use uvll;
+use homing::{HomingIO, HomeHandle};
 use pipe::PipeWatcher;
+use super::{UvHandle, UvError, uv_error_to_io_error,
+            wait_until_woken_after, wakeup};
+use uvio::UvIoFactory;
+use uvll;
 
 pub struct Process {
     handle: *uvll::uv_process_t,
-    home: SchedHandle,
+    home: HomeHandle,
 
     /// Task to wake up (may be null) for when the process exits
     to_wake: Option<BlockedTask>,
 
     /// Collected from the exit_cb
-    exit_status: Option<ProcessExit>,
+    exit_status: Option<process::ProcessExit>,
 }
 
 impl Process {
@@ -41,7 +40,7 @@ impl Process {
     ///
     /// Returns either the corresponding process object or an error which
     /// occurred.
-    pub fn spawn(loop_: &Loop, config: ProcessConfig)
+    pub fn spawn(io_loop: &mut UvIoFactory, config: process::ProcessConfig)
                 -> Result<(~Process, ~[Option<PipeWatcher>]), UvError>
     {
         let cwd = config.cwd.map(|s| s.to_c_str());
@@ -52,7 +51,7 @@ impl Process {
             stdio.set_len(io.len());
             for (slot, other) in stdio.iter().zip(io.iter()) {
                 let io = set_stdio(slot as *uvll::uv_stdio_container_t, other,
-                                   loop_);
+                                   io_loop);
                 ret_io.push(io);
             }
         }
@@ -78,12 +77,12 @@ impl Process {
                 let handle = UvHandle::alloc(None::<Process>, uvll::UV_PROCESS);
                 let process = ~Process {
                     handle: handle,
-                    home: get_handle_to_current_scheduler!(),
+                    home: io_loop.make_handle(),
                     to_wake: None,
                     exit_status: None,
                 };
                 match unsafe {
-                    uvll::uv_spawn(loop_.handle, handle, &options)
+                    uvll::uv_spawn(io_loop.uv_loop(), handle, &options)
                 } {
                     0 => Ok(process.install()),
                     err => Err(UvError(err)),
@@ -105,33 +104,28 @@ extern fn on_exit(handle: *uvll::uv_process_t,
 
     assert!(p.exit_status.is_none());
     p.exit_status = Some(match term_signal {
-        0 => ExitStatus(exit_status as int),
-        n => ExitSignal(n as int),
+        0 => process::ExitStatus(exit_status as int),
+        n => process::ExitSignal(n as int),
     });
 
-    match p.to_wake.take() {
-        Some(task) => {
-            let scheduler: ~Scheduler = Local::take();
-            scheduler.resume_blocked_task_immediately(task);
-        }
-        None => {}
-    }
+    if p.to_wake.is_none() { return }
+    wakeup(&mut p.to_wake);
 }
 
 unsafe fn set_stdio(dst: *uvll::uv_stdio_container_t,
-                    io: &StdioContainer,
-                    loop_: &Loop) -> Option<PipeWatcher> {
+                    io: &process::StdioContainer,
+                    io_loop: &mut UvIoFactory) -> Option<PipeWatcher> {
     match *io {
-        Ignored => {
+        process::Ignored => {
             uvll::set_stdio_container_flags(dst, uvll::STDIO_IGNORE);
             None
         }
-        InheritFd(fd) => {
+        process::InheritFd(fd) => {
             uvll::set_stdio_container_flags(dst, uvll::STDIO_INHERIT_FD);
             uvll::set_stdio_container_fd(dst, fd);
             None
         }
-        CreatePipe(readable, writable) => {
+        process::CreatePipe(readable, writable) => {
             let mut flags = uvll::STDIO_CREATE_PIPE as libc::c_int;
             if readable {
                 flags |= uvll::STDIO_READABLE_PIPE as libc::c_int;
@@ -139,7 +133,7 @@ unsafe fn set_stdio(dst: *uvll::uv_stdio_container_t,
             if writable {
                 flags |= uvll::STDIO_WRITABLE_PIPE as libc::c_int;
             }
-            let pipe = PipeWatcher::new(loop_, false);
+            let pipe = PipeWatcher::new(io_loop, false);
             uvll::set_stdio_container_flags(dst, flags);
             uvll::set_stdio_container_stream(dst, pipe.handle());
             Some(pipe)
@@ -186,7 +180,7 @@ fn with_env<T>(env: Option<&[(~str, ~str)]>, f: |**libc::c_char| -> T) -> T {
 }
 
 impl HomingIO for Process {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl UvHandle<uvll::uv_process_t> for Process {
@@ -208,7 +202,7 @@ impl RtioProcess for Process {
         }
     }
 
-    fn wait(&mut self) -> ProcessExit {
+    fn wait(&mut self) -> process::ProcessExit {
         // Make sure (on the home scheduler) that we have an exit status listed
         let _m = self.fire_homing_missile();
         match self.exit_status {
diff --git a/src/librustuv/queue.rs b/src/librustuv/queue.rs
new file mode 100644
index 00000000000..32f8d8532a2
--- /dev/null
+++ b/src/librustuv/queue.rs
@@ -0,0 +1,192 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A concurrent queue used to signal remote event loops
+//!
+//! This queue implementation is used to send tasks among event loops. This is
+//! backed by a multi-producer/single-consumer queue from libstd and uv_async_t
+//! handles (to wake up a remote event loop).
+//!
+//! The uv_async_t is stored next to the event loop, so in order to not keep the
+//! event loop alive we use uv_ref and uv_unref in order to control when the
+//! async handle is active or not.
+
+#[allow(dead_code)];
+
+use std::cast;
+use std::libc::{c_void, c_int};
+use std::rt::task::BlockedTask;
+use std::unstable::sync::LittleLock;
+use mpsc = std::sync::mpsc_queue;
+
+use async::AsyncWatcher;
+use super::{Loop, UvHandle};
+use uvll;
+
+enum Message {
+    Task(BlockedTask),
+    Increment,
+    Decrement,
+}
+
+struct State {
+    handle: *uvll::uv_async_t,
+    lock: LittleLock, // see comments in async_cb for why this is needed
+}
+
+/// This structure is intended to be stored next to the event loop, and it is
+/// used to create new `Queue` structures.
+pub struct QueuePool {
+    priv producer: mpsc::Producer<Message, State>,
+    priv consumer: mpsc::Consumer<Message, State>,
+    priv refcnt: uint,
+}
+
+/// This type is used to send messages back to the original event loop.
+pub struct Queue {
+    priv queue: mpsc::Producer<Message, State>,
+}
+
+extern fn async_cb(handle: *uvll::uv_async_t, status: c_int) {
+    assert_eq!(status, 0);
+    let state: &mut QueuePool = unsafe {
+        cast::transmute(uvll::get_data_for_uv_handle(handle))
+    };
+    let packet = unsafe { state.consumer.packet() };
+
+    // Remember that there is no guarantee about how many times an async
+    // callback is called with relation to the number of sends, so process the
+    // entire queue in a loop.
+    loop {
+        match state.consumer.pop() {
+            mpsc::Data(Task(task)) => {
+                task.wake().map(|t| t.reawaken(true));
+            }
+            mpsc::Data(Increment) => unsafe {
+                if state.refcnt == 0 {
+                    uvll::uv_ref((*packet).handle);
+                }
+                state.refcnt += 1;
+            },
+            mpsc::Data(Decrement) => unsafe {
+                state.refcnt -= 1;
+                if state.refcnt == 0 {
+                    uvll::uv_unref((*packet).handle);
+                }
+            },
+            mpsc::Empty | mpsc::Inconsistent => break
+        };
+    }
+
+    // If the refcount is now zero after processing the queue, then there is no
+    // longer a reference on the async handle and it is possible that this event
+    // loop can exit. What we're not guaranteed, however, is that a producer in
+    // the middle of dropping itself is yet done with the handle. It could be
+    // possible that we saw their Decrement message but they have yet to signal
+    // on the async handle. If we were to return immediately, the entire uv loop
+    // could be destroyed meaning the call to uv_async_send would abort()
+    //
+    // In order to fix this, an OS mutex is used to wait for the other end to
+    // finish before we continue. The drop block on a handle will acquire a
+    // mutex and then drop it after both the push and send have been completed.
+    // If we acquire the mutex here, then we are guaranteed that there are no
+    // longer any senders which are holding on to their handles, so we can
+    // safely allow the event loop to exit.
+    if state.refcnt == 0 {
+        unsafe {
+            let _l = (*packet).lock.lock();
+        }
+    }
+}
+
+impl QueuePool {
+    pub fn new(loop_: &mut Loop) -> ~QueuePool {
+        let handle = UvHandle::alloc(None::<AsyncWatcher>, uvll::UV_ASYNC);
+        let (c, p) = mpsc::queue(State {
+            handle: handle,
+            lock: LittleLock::new(),
+        });
+        let q = ~QueuePool {
+            producer: p,
+            consumer: c,
+            refcnt: 0,
+        };
+
+        unsafe {
+            assert_eq!(uvll::uv_async_init(loop_.handle, handle, async_cb), 0);
+            uvll::uv_unref(handle);
+            let data: *c_void = *cast::transmute::<&~QueuePool, &*c_void>(&q);
+            uvll::set_data_for_uv_handle(handle, data);
+        }
+
+        return q;
+    }
+
+    pub fn queue(&mut self) -> Queue {
+        unsafe {
+            if self.refcnt == 0 {
+                uvll::uv_ref((*self.producer.packet()).handle);
+            }
+            self.refcnt += 1;
+        }
+        Queue { queue: self.producer.clone() }
+    }
+
+    pub fn handle(&self) -> *uvll::uv_async_t {
+        unsafe { (*self.producer.packet()).handle }
+    }
+}
+
+impl Queue {
+    pub fn push(&mut self, task: BlockedTask) {
+        self.queue.push(Task(task));
+        unsafe {
+            uvll::uv_async_send((*self.queue.packet()).handle);
+        }
+    }
+}
+
+impl Clone for Queue {
+    fn clone(&self) -> Queue {
+        // Push a request to increment on the queue, but there's no need to
+        // signal the event loop to process it at this time. We're guaranteed
+        // that the count is at least one (because we have a queue right here),
+        // and if the queue is dropped later on it'll see the increment for the
+        // decrement anyway.
+        unsafe {
+            cast::transmute_mut(self).queue.push(Increment);
+        }
+        Queue { queue: self.queue.clone() }
+    }
+}
+
+impl Drop for Queue {
+    fn drop(&mut self) {
+        // See the comments in the async_cb function for why there is a lock
+        // that is acquired only on a drop.
+        unsafe {
+            let state = self.queue.packet();
+            let _l = (*state).lock.lock();
+            self.queue.push(Decrement);
+            uvll::uv_async_send((*state).handle);
+        }
+    }
+}
+
+impl Drop for State {
+    fn drop(&mut self) {
+        unsafe {
+            uvll::uv_close(self.handle, cast::transmute(0));
+            // Note that this does *not* free the handle, that is the
+            // responsibility of the caller because the uv loop must be closed
+            // before we deallocate this uv handle.
+        }
+    }
+}
diff --git a/src/librustuv/signal.rs b/src/librustuv/signal.rs
index f082aef003c..6772c6d1936 100644
--- a/src/librustuv/signal.rs
+++ b/src/librustuv/signal.rs
@@ -10,34 +10,33 @@
 
 use std::libc::c_int;
 use std::io::signal::Signum;
-use std::rt::sched::{SchedHandle, Scheduler};
 use std::comm::SharedChan;
-use std::rt::local::Local;
 use std::rt::rtio::RtioSignal;
 
-use super::{Loop, UvError, UvHandle};
+use homing::{HomingIO, HomeHandle};
+use super::{UvError, UvHandle};
 use uvll;
-use uvio::HomingIO;
+use uvio::UvIoFactory;
 
 pub struct SignalWatcher {
     handle: *uvll::uv_signal_t,
-    home: SchedHandle,
+    home: HomeHandle,
 
     channel: SharedChan<Signum>,
     signal: Signum,
 }
 
 impl SignalWatcher {
-    pub fn new(loop_: &mut Loop, signum: Signum,
+    pub fn new(io: &mut UvIoFactory, signum: Signum,
                channel: SharedChan<Signum>) -> Result<~SignalWatcher, UvError> {
         let s = ~SignalWatcher {
             handle: UvHandle::alloc(None::<SignalWatcher>, uvll::UV_SIGNAL),
-            home: get_handle_to_current_scheduler!(),
+            home: io.make_handle(),
             channel: channel,
             signal: signum,
         };
         assert_eq!(unsafe {
-            uvll::uv_signal_init(loop_.handle, s.handle)
+            uvll::uv_signal_init(io.uv_loop(), s.handle)
         }, 0);
 
         match unsafe {
@@ -53,11 +52,11 @@ impl SignalWatcher {
 extern fn signal_cb(handle: *uvll::uv_signal_t, signum: c_int) {
     let s: &mut SignalWatcher = unsafe { UvHandle::from_uv_handle(&handle) };
     assert_eq!(signum as int, s.signal as int);
-    s.channel.send_deferred(s.signal);
+    s.channel.try_send(s.signal);
 }
 
 impl HomingIO for SignalWatcher {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl UvHandle<uvll::uv_signal_t> for SignalWatcher {
@@ -69,15 +68,15 @@ impl RtioSignal for SignalWatcher {}
 impl Drop for SignalWatcher {
     fn drop(&mut self) {
         let _m = self.fire_homing_missile();
-        self.close_async_();
+        self.close();
     }
 }
 
 #[cfg(test)]
 mod test {
-    use super::*;
     use super::super::local_loop;
     use std::io::signal;
+    use super::SignalWatcher;
 
     #[test]
     fn closing_channel_during_drop_doesnt_kill_everything() {
diff --git a/src/librustuv/stream.rs b/src/librustuv/stream.rs
index 0304b89dd6f..73173fc677e 100644
--- a/src/librustuv/stream.rs
+++ b/src/librustuv/stream.rs
@@ -11,12 +11,10 @@
 use std::cast;
 use std::libc::{c_int, size_t, ssize_t};
 use std::ptr;
-use std::rt::BlockedTask;
-use std::rt::local::Local;
-use std::rt::sched::Scheduler;
+use std::rt::task::BlockedTask;
 
 use super::{UvError, Buf, slice_to_uv_buf, Request, wait_until_woken_after,
-            ForbidUnwind};
+            ForbidUnwind, wakeup};
 use uvll;
 
 // This is a helper structure which is intended to get embedded into other
@@ -164,8 +162,7 @@ extern fn read_cb(handle: *uvll::uv_stream_t, nread: ssize_t, _buf: *Buf) {
     unsafe { assert_eq!(uvll::uv_read_stop(handle), 0); }
     rcx.result = nread;
 
-    let scheduler: ~Scheduler = Local::take();
-    scheduler.resume_blocked_task_immediately(rcx.task.take_unwrap());
+    wakeup(&mut rcx.task);
 }
 
 // Unlike reading, the WriteContext is stored in the uv_write_t request. Like
@@ -180,6 +177,5 @@ extern fn write_cb(req: *uvll::uv_write_t, status: c_int) {
     wcx.result = status;
     req.defuse();
 
-    let sched: ~Scheduler = Local::take();
-    sched.resume_blocked_task_immediately(wcx.task.take_unwrap());
+    wakeup(&mut wcx.task);
 }
diff --git a/src/librustuv/timer.rs b/src/librustuv/timer.rs
index ab143d6e8b0..4a0ad44d311 100644
--- a/src/librustuv/timer.rs
+++ b/src/librustuv/timer.rs
@@ -9,19 +9,19 @@
 // except according to those terms.
 
 use std::libc::c_int;
-use std::rt::BlockedTask;
 use std::rt::local::Local;
 use std::rt::rtio::RtioTimer;
-use std::rt::sched::{Scheduler, SchedHandle};
+use std::rt::task::{BlockedTask, Task};
 use std::util;
 
+use homing::{HomeHandle, HomingIO};
+use super::{UvHandle, ForbidUnwind, ForbidSwitch};
+use uvio::UvIoFactory;
 use uvll;
-use super::{Loop, UvHandle, ForbidUnwind, ForbidSwitch};
-use uvio::HomingIO;
 
 pub struct TimerWatcher {
     handle: *uvll::uv_timer_t,
-    home: SchedHandle,
+    home: HomeHandle,
     action: Option<NextAction>,
     id: uint, // see comments in timer_cb
 }
@@ -33,15 +33,15 @@ pub enum NextAction {
 }
 
 impl TimerWatcher {
-    pub fn new(loop_: &mut Loop) -> ~TimerWatcher {
+    pub fn new(io: &mut UvIoFactory) -> ~TimerWatcher {
         let handle = UvHandle::alloc(None::<TimerWatcher>, uvll::UV_TIMER);
         assert_eq!(unsafe {
-            uvll::uv_timer_init(loop_.handle, handle)
+            uvll::uv_timer_init(io.uv_loop(), handle)
         }, 0);
         let me = ~TimerWatcher {
             handle: handle,
             action: None,
-            home: get_handle_to_current_scheduler!(),
+            home: io.make_handle(),
             id: 0,
         };
         return me.install();
@@ -59,7 +59,7 @@ impl TimerWatcher {
 }
 
 impl HomingIO for TimerWatcher {
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle { &mut self.home }
+    fn home<'r>(&'r mut self) -> &'r mut HomeHandle { &mut self.home }
 }
 
 impl UvHandle<uvll::uv_timer_t> for TimerWatcher {
@@ -89,10 +89,11 @@ impl RtioTimer for TimerWatcher {
         // started, then we need to call stop on the timer.
         let _f = ForbidUnwind::new("timer");
 
-        let sched: ~Scheduler = Local::take();
-        sched.deschedule_running_task_and_then(|_sched, task| {
+        let task: ~Task = Local::take();
+        task.deschedule(1, |task| {
             self.action = Some(WakeTask(task));
             self.start(msecs, 0);
+            Ok(())
         });
         self.stop();
     }
@@ -137,12 +138,11 @@ extern fn timer_cb(handle: *uvll::uv_timer_t, status: c_int) {
 
     match timer.action.take_unwrap() {
         WakeTask(task) => {
-            let sched: ~Scheduler = Local::take();
-            sched.resume_blocked_task_immediately(task);
+            task.wake().map(|t| t.reawaken(true));
         }
-        SendOnce(chan) => { chan.try_send_deferred(()); }
+        SendOnce(chan) => { chan.try_send(()); }
         SendMany(chan, id) => {
-            chan.try_send_deferred(());
+            chan.try_send(());
 
             // Note that the above operation could have performed some form of
             // scheduling. This means that the timer may have decided to insert
@@ -169,7 +169,7 @@ impl Drop for TimerWatcher {
         let _action = {
             let _m = self.fire_homing_missile();
             self.stop();
-            self.close_async_();
+            self.close();
             self.action.take()
         };
     }
@@ -177,9 +177,9 @@ impl Drop for TimerWatcher {
 
 #[cfg(test)]
 mod test {
-    use super::*;
     use std::rt::rtio::RtioTimer;
     use super::super::local_loop;
+    use super::TimerWatcher;
 
     #[test]
     fn oneshot() {
@@ -207,9 +207,9 @@ mod test {
         let port = timer.period(1);
         port.recv();
         port.recv();
-        let port = timer.period(1);
-        port.recv();
-        port.recv();
+        let port2 = timer.period(1);
+        port2.recv();
+        port2.recv();
     }
 
     #[test]
diff --git a/src/librustuv/tty.rs b/src/librustuv/tty.rs
index fcad6296579..0e76ed9feb9 100644
--- a/src/librustuv/tty.rs
+++ b/src/librustuv/tty.rs
@@ -10,24 +10,23 @@
 
 use std::libc;
 use std::io::IoError;
-use std::rt::local::Local;
 use std::rt::rtio::RtioTTY;
-use std::rt::sched::{Scheduler, SchedHandle};
 
+use homing::{HomingIO, HomeHandle};
 use stream::StreamWatcher;
-use super::{Loop, UvError, UvHandle, uv_error_to_io_error};
-use uvio::HomingIO;
+use super::{UvError, UvHandle, uv_error_to_io_error};
+use uvio::UvIoFactory;
 use uvll;
 
 pub struct TtyWatcher{
     tty: *uvll::uv_tty_t,
     stream: StreamWatcher,
-    home: SchedHandle,
+    home: HomeHandle,
     fd: libc::c_int,
 }
 
 impl TtyWatcher {
-    pub fn new(loop_: &Loop, fd: libc::c_int, readable: bool)
+    pub fn new(io: &mut UvIoFactory, fd: libc::c_int, readable: bool)
         -> Result<TtyWatcher, UvError>
     {
         // libuv may succeed in giving us a handle (via uv_tty_init), but if the
@@ -56,14 +55,14 @@ impl TtyWatcher {
         // with attempting to open it as a tty.
         let handle = UvHandle::alloc(None::<TtyWatcher>, uvll::UV_TTY);
         match unsafe {
-            uvll::uv_tty_init(loop_.handle, handle, fd as libc::c_int,
+            uvll::uv_tty_init(io.uv_loop(), handle, fd as libc::c_int,
                               readable as libc::c_int)
         } {
             0 => {
                 Ok(TtyWatcher {
                     tty: handle,
                     stream: StreamWatcher::new(handle),
-                    home: get_handle_to_current_scheduler!(),
+                    home: io.make_handle(),
                     fd: fd,
                 })
             }
@@ -120,7 +119,7 @@ impl UvHandle<uvll::uv_tty_t> for TtyWatcher {
 }
 
 impl HomingIO for TtyWatcher {
-    fn home<'a>(&'a mut self) -> &'a mut SchedHandle { &mut self.home }
+    fn home<'a>(&'a mut self) -> &'a mut HomeHandle { &mut self.home }
 }
 
 impl Drop for TtyWatcher {
diff --git a/src/librustuv/uvio.rs b/src/librustuv/uvio.rs
index c556b96671a..dbf129d0b69 100644
--- a/src/librustuv/uvio.rs
+++ b/src/librustuv/uvio.rs
@@ -9,121 +9,41 @@
 // except according to those terms.
 
 use std::c_str::CString;
+use std::cast;
 use std::comm::SharedChan;
-use std::libc::c_int;
-use std::libc;
-use std::path::Path;
 use std::io::IoError;
 use std::io::net::ip::SocketAddr;
 use std::io::process::ProcessConfig;
-use std::io;
-use std::rt::local::Local;
-use std::rt::rtio::*;
-use std::rt::sched::{Scheduler, SchedHandle};
-use std::rt::task::Task;
-use std::libc::{O_CREAT, O_APPEND, O_TRUNC, O_RDWR, O_RDONLY, O_WRONLY,
-                S_IRUSR, S_IWUSR};
-use std::io::{FileMode, FileAccess, Open, Append, Truncate, Read, Write,
-                  ReadWrite, FileStat};
 use std::io::signal::Signum;
+use std::io::{FileMode, FileAccess, Open, Append, Truncate, Read, Write,
+              ReadWrite, FileStat};
+use std::io;
+use std::libc::c_int;
+use std::libc::{O_CREAT, O_APPEND, O_TRUNC, O_RDWR, O_RDONLY, O_WRONLY, S_IRUSR,
+                S_IWUSR};
+use std::libc;
+use std::path::Path;
+use std::rt::rtio;
+use std::rt::rtio::IoFactory;
 use ai = std::io::net::addrinfo;
 
 #[cfg(test)] use std::unstable::run_in_bare_thread;
 
-use super::*;
+use super::{uv_error_to_io_error, Loop};
+
 use addrinfo::GetAddrInfoRequest;
-
-pub trait HomingIO {
-
-    fn home<'r>(&'r mut self) -> &'r mut SchedHandle;
-
-    /// This function will move tasks to run on their home I/O scheduler. Note
-    /// that this function does *not* pin the task to the I/O scheduler, but
-    /// rather it simply moves it to running on the I/O scheduler.
-    fn go_to_IO_home(&mut self) -> uint {
-        use std::rt::sched::RunOnce;
-
-        let _f = ForbidUnwind::new("going home");
-
-        let current_sched_id = {
-            let mut sched = Local::borrow(None::<Scheduler>);
-            sched.get().sched_id()
-        };
-
-        // Only need to invoke a context switch if we're not on the right
-        // scheduler.
-        if current_sched_id != self.home().sched_id {
-            let scheduler: ~Scheduler = Local::take();
-            scheduler.deschedule_running_task_and_then(|_, task| {
-                task.wake().map(|task| {
-                    self.home().send(RunOnce(task));
-                });
-            })
-        }
-        let current_sched_id = {
-            let mut sched = Local::borrow(None::<Scheduler>);
-            sched.get().sched_id()
-        };
-        assert!(current_sched_id == self.home().sched_id);
-
-        self.home().sched_id
-    }
-
-    /// Fires a single homing missile, returning another missile targeted back
-    /// at the original home of this task. In other words, this function will
-    /// move the local task to its I/O scheduler and then return an RAII wrapper
-    /// which will return the task home.
-    fn fire_homing_missile(&mut self) -> HomingMissile {
-        HomingMissile { io_home: self.go_to_IO_home() }
-    }
-
-    /// Same as `fire_homing_missile`, but returns the local I/O scheduler as
-    /// well (the one that was homed to).
-    fn fire_homing_missile_sched(&mut self) -> (HomingMissile, ~Scheduler) {
-        // First, transplant ourselves to the home I/O scheduler
-        let missile = self.fire_homing_missile();
-        // Next (must happen next), grab the local I/O scheduler
-        let io_sched: ~Scheduler = Local::take();
-
-        (missile, io_sched)
-    }
-}
-
-/// After a homing operation has been completed, this will return the current
-/// task back to its appropriate home (if applicable). The field is used to
-/// assert that we are where we think we are.
-struct HomingMissile {
-    priv io_home: uint,
-}
-
-impl HomingMissile {
-    pub fn check(&self, msg: &'static str) {
-        let mut sched = Local::borrow(None::<Scheduler>);
-        let local_id = sched.get().sched_id();
-        assert!(local_id == self.io_home, "{}", msg);
-    }
-}
-
-impl Drop for HomingMissile {
-    fn drop(&mut self) {
-        let _f = ForbidUnwind::new("leaving home");
-
-        // It would truly be a sad day if we had moved off the home I/O
-        // scheduler while we were doing I/O.
-        self.check("task moved away from the home scheduler");
-
-        // If we were a homed task, then we must send ourselves back to the
-        // original scheduler. Otherwise, we can just return and keep running
-        if !Task::on_appropriate_sched() {
-            let scheduler: ~Scheduler = Local::take();
-            scheduler.deschedule_running_task_and_then(|_, task| {
-                task.wake().map(|task| {
-                    Scheduler::run_task(task);
-                });
-            })
-        }
-    }
-}
+use async::AsyncWatcher;
+use file::{FsRequest, FileWatcher};
+use queue::QueuePool;
+use homing::HomeHandle;
+use idle::IdleWatcher;
+use net::{TcpWatcher, TcpListener, UdpWatcher};
+use pipe::{PipeWatcher, PipeListener};
+use process::Process;
+use signal::SignalWatcher;
+use timer::TimerWatcher;
+use tty::TtyWatcher;
+use uvll;
 
 // Obviously an Event Loop is always home.
 pub struct UvEventLoop {
@@ -132,49 +52,65 @@ pub struct UvEventLoop {
 
 impl UvEventLoop {
     pub fn new() -> UvEventLoop {
+        let mut loop_ = Loop::new();
+        let handle_pool = QueuePool::new(&mut loop_);
         UvEventLoop {
-            uvio: UvIoFactory(Loop::new())
+            uvio: UvIoFactory {
+                loop_: loop_,
+                handle_pool: Some(handle_pool),
+            }
         }
     }
 }
 
 impl Drop for UvEventLoop {
     fn drop(&mut self) {
-        self.uvio.uv_loop().close();
+        // Must first destroy the pool of handles before we destroy the loop
+        // because otherwise the contained async handle will be destroyed after
+        // the loop is free'd (use-after-free). We also must free the uv handle
+        // after the loop has been closed because during the closing of the loop
+        // the handle is required to be used apparently.
+        let handle = self.uvio.handle_pool.get_ref().handle();
+        self.uvio.handle_pool.take();
+        self.uvio.loop_.close();
+        unsafe { uvll::free_handle(handle) }
     }
 }
 
-impl EventLoop for UvEventLoop {
+impl rtio::EventLoop for UvEventLoop {
     fn run(&mut self) {
-        self.uvio.uv_loop().run();
+        self.uvio.loop_.run();
     }
 
     fn callback(&mut self, f: proc()) {
-        IdleWatcher::onetime(self.uvio.uv_loop(), f);
+        IdleWatcher::onetime(&mut self.uvio.loop_, f);
     }
 
-    fn pausable_idle_callback(&mut self, cb: ~Callback) -> ~PausableIdleCallback {
-        IdleWatcher::new(self.uvio.uv_loop(), cb) as ~PausableIdleCallback
+    fn pausable_idle_callback(&mut self, cb: ~rtio::Callback)
+        -> ~rtio::PausableIdleCallback
+    {
+        IdleWatcher::new(&mut self.uvio.loop_, cb) as ~rtio::PausableIdleCallback
     }
 
-    fn remote_callback(&mut self, f: ~Callback) -> ~RemoteCallback {
-        ~AsyncWatcher::new(self.uvio.uv_loop(), f) as ~RemoteCallback
+    fn remote_callback(&mut self, f: ~rtio::Callback) -> ~rtio::RemoteCallback {
+        ~AsyncWatcher::new(&mut self.uvio.loop_, f) as ~rtio::RemoteCallback
     }
 
-    fn io<'a>(&'a mut self) -> Option<&'a mut IoFactory> {
-        let factory = &mut self.uvio as &mut IoFactory;
+    fn io<'a>(&'a mut self) -> Option<&'a mut rtio::IoFactory> {
+        let factory = &mut self.uvio as &mut rtio::IoFactory;
         Some(factory)
     }
 }
 
 #[cfg(not(test))]
 #[lang = "event_loop_factory"]
-pub extern "C" fn new_loop() -> ~EventLoop {
-    ~UvEventLoop::new() as ~EventLoop
+pub fn new_loop() -> ~rtio::EventLoop {
+    ~UvEventLoop::new() as ~rtio::EventLoop
 }
 
 #[test]
 fn test_callback_run_once() {
+    use std::rt::rtio::EventLoop;
     do run_in_bare_thread {
         let mut event_loop = UvEventLoop::new();
         let mut count = 0;
@@ -187,11 +123,19 @@ fn test_callback_run_once() {
     }
 }
 
-pub struct UvIoFactory(Loop);
+pub struct UvIoFactory {
+    loop_: Loop,
+    priv handle_pool: Option<~QueuePool>,
+}
 
 impl UvIoFactory {
-    pub fn uv_loop<'a>(&'a mut self) -> &'a mut Loop {
-        match self { &UvIoFactory(ref mut ptr) => ptr }
+    pub fn uv_loop<'a>(&mut self) -> *uvll::uv_loop_t { self.loop_.handle }
+
+    pub fn make_handle(&mut self) -> HomeHandle {
+        // It's understood by the homing code that the "local id" is just the
+        // pointer of the local I/O factory cast to a uint.
+        let id: uint = unsafe { cast::transmute_copy(&self) };
+        HomeHandle::new(id, &mut **self.handle_pool.get_mut_ref())
     }
 }
 
@@ -200,46 +144,45 @@ impl IoFactory for UvIoFactory {
     // NB: This blocks the task waiting on the connection.
     // It would probably be better to return a future
     fn tcp_connect(&mut self, addr: SocketAddr)
-        -> Result<~RtioTcpStream, IoError>
+        -> Result<~rtio::RtioTcpStream, IoError>
     {
-        match TcpWatcher::connect(self.uv_loop(), addr) {
-            Ok(t) => Ok(~t as ~RtioTcpStream),
+        match TcpWatcher::connect(self, addr) {
+            Ok(t) => Ok(~t as ~rtio::RtioTcpStream),
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
 
-    fn tcp_bind(&mut self, addr: SocketAddr) -> Result<~RtioTcpListener, IoError> {
-        match TcpListener::bind(self.uv_loop(), addr) {
-            Ok(t) => Ok(t as ~RtioTcpListener),
+    fn tcp_bind(&mut self, addr: SocketAddr) -> Result<~rtio::RtioTcpListener, IoError> {
+        match TcpListener::bind(self, addr) {
+            Ok(t) => Ok(t as ~rtio::RtioTcpListener),
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
 
-    fn udp_bind(&mut self, addr: SocketAddr) -> Result<~RtioUdpSocket, IoError> {
-        match UdpWatcher::bind(self.uv_loop(), addr) {
-            Ok(u) => Ok(~u as ~RtioUdpSocket),
+    fn udp_bind(&mut self, addr: SocketAddr) -> Result<~rtio::RtioUdpSocket, IoError> {
+        match UdpWatcher::bind(self, addr) {
+            Ok(u) => Ok(~u as ~rtio::RtioUdpSocket),
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
 
-    fn timer_init(&mut self) -> Result<~RtioTimer, IoError> {
-        Ok(TimerWatcher::new(self.uv_loop()) as ~RtioTimer)
+    fn timer_init(&mut self) -> Result<~rtio::RtioTimer, IoError> {
+        Ok(TimerWatcher::new(self) as ~rtio::RtioTimer)
     }
 
     fn get_host_addresses(&mut self, host: Option<&str>, servname: Option<&str>,
                           hint: Option<ai::Hint>) -> Result<~[ai::Info], IoError> {
-        let r = GetAddrInfoRequest::run(self.uv_loop(), host, servname, hint);
+        let r = GetAddrInfoRequest::run(&self.loop_, host, servname, hint);
         r.map_err(uv_error_to_io_error)
     }
 
     fn fs_from_raw_fd(&mut self, fd: c_int,
-                      close: CloseBehavior) -> ~RtioFileStream {
-        let loop_ = Loop::wrap(self.uv_loop().handle);
-        ~FileWatcher::new(loop_, fd, close) as ~RtioFileStream
+                      close: rtio::CloseBehavior) -> ~rtio::RtioFileStream {
+        ~FileWatcher::new(self, fd, close) as ~rtio::RtioFileStream
     }
 
     fn fs_open(&mut self, path: &CString, fm: FileMode, fa: FileAccess)
-        -> Result<~RtioFileStream, IoError> {
+        -> Result<~rtio::RtioFileStream, IoError> {
         let flags = match fm {
             io::Open => 0,
             io::Append => libc::O_APPEND,
@@ -254,117 +197,117 @@ impl IoFactory for UvIoFactory {
                               libc::S_IRUSR | libc::S_IWUSR),
         };
 
-        match FsRequest::open(self.uv_loop(), path, flags as int, mode as int) {
-            Ok(fs) => Ok(~fs as ~RtioFileStream),
+        match FsRequest::open(self, path, flags as int, mode as int) {
+            Ok(fs) => Ok(~fs as ~rtio::RtioFileStream),
             Err(e) => Err(uv_error_to_io_error(e))
         }
     }
 
     fn fs_unlink(&mut self, path: &CString) -> Result<(), IoError> {
-        let r = FsRequest::unlink(self.uv_loop(), path);
+        let r = FsRequest::unlink(&self.loop_, path);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_lstat(&mut self, path: &CString) -> Result<FileStat, IoError> {
-        let r = FsRequest::lstat(self.uv_loop(), path);
+        let r = FsRequest::lstat(&self.loop_, path);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_stat(&mut self, path: &CString) -> Result<FileStat, IoError> {
-        let r = FsRequest::stat(self.uv_loop(), path);
+        let r = FsRequest::stat(&self.loop_, path);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_mkdir(&mut self, path: &CString,
                 perm: io::FilePermission) -> Result<(), IoError> {
-        let r = FsRequest::mkdir(self.uv_loop(), path, perm as c_int);
+        let r = FsRequest::mkdir(&self.loop_, path, perm as c_int);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_rmdir(&mut self, path: &CString) -> Result<(), IoError> {
-        let r = FsRequest::rmdir(self.uv_loop(), path);
+        let r = FsRequest::rmdir(&self.loop_, path);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_rename(&mut self, path: &CString, to: &CString) -> Result<(), IoError> {
-        let r = FsRequest::rename(self.uv_loop(), path, to);
+        let r = FsRequest::rename(&self.loop_, path, to);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_chmod(&mut self, path: &CString,
                 perm: io::FilePermission) -> Result<(), IoError> {
-        let r = FsRequest::chmod(self.uv_loop(), path, perm as c_int);
+        let r = FsRequest::chmod(&self.loop_, path, perm as c_int);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_readdir(&mut self, path: &CString, flags: c_int)
         -> Result<~[Path], IoError>
     {
-        let r = FsRequest::readdir(self.uv_loop(), path, flags);
+        let r = FsRequest::readdir(&self.loop_, path, flags);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_link(&mut self, src: &CString, dst: &CString) -> Result<(), IoError> {
-        let r = FsRequest::link(self.uv_loop(), src, dst);
+        let r = FsRequest::link(&self.loop_, src, dst);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_symlink(&mut self, src: &CString, dst: &CString) -> Result<(), IoError> {
-        let r = FsRequest::symlink(self.uv_loop(), src, dst);
+        let r = FsRequest::symlink(&self.loop_, src, dst);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_chown(&mut self, path: &CString, uid: int, gid: int) -> Result<(), IoError> {
-        let r = FsRequest::chown(self.uv_loop(), path, uid, gid);
+        let r = FsRequest::chown(&self.loop_, path, uid, gid);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_readlink(&mut self, path: &CString) -> Result<Path, IoError> {
-        let r = FsRequest::readlink(self.uv_loop(), path);
+        let r = FsRequest::readlink(&self.loop_, path);
         r.map_err(uv_error_to_io_error)
     }
     fn fs_utime(&mut self, path: &CString, atime: u64, mtime: u64)
         -> Result<(), IoError>
     {
-        let r = FsRequest::utime(self.uv_loop(), path, atime, mtime);
+        let r = FsRequest::utime(&self.loop_, path, atime, mtime);
         r.map_err(uv_error_to_io_error)
     }
 
     fn spawn(&mut self, config: ProcessConfig)
-            -> Result<(~RtioProcess, ~[Option<~RtioPipe>]), IoError>
+            -> Result<(~rtio::RtioProcess, ~[Option<~rtio::RtioPipe>]), IoError>
     {
-        match Process::spawn(self.uv_loop(), config) {
+        match Process::spawn(self, config) {
             Ok((p, io)) => {
-                Ok((p as ~RtioProcess,
-                    io.move_iter().map(|i| i.map(|p| ~p as ~RtioPipe)).collect()))
+                Ok((p as ~rtio::RtioProcess,
+                    io.move_iter().map(|i| i.map(|p| ~p as ~rtio::RtioPipe)).collect()))
             }
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
 
-    fn unix_bind(&mut self, path: &CString) -> Result<~RtioUnixListener, IoError>
+    fn unix_bind(&mut self, path: &CString) -> Result<~rtio::RtioUnixListener, IoError>
     {
-        match PipeListener::bind(self.uv_loop(), path) {
-            Ok(p) => Ok(p as ~RtioUnixListener),
+        match PipeListener::bind(self, path) {
+            Ok(p) => Ok(p as ~rtio::RtioUnixListener),
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
 
-    fn unix_connect(&mut self, path: &CString) -> Result<~RtioPipe, IoError> {
-        match PipeWatcher::connect(self.uv_loop(), path) {
-            Ok(p) => Ok(~p as ~RtioPipe),
+    fn unix_connect(&mut self, path: &CString) -> Result<~rtio::RtioPipe, IoError> {
+        match PipeWatcher::connect(self, path) {
+            Ok(p) => Ok(~p as ~rtio::RtioPipe),
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
 
     fn tty_open(&mut self, fd: c_int, readable: bool)
-            -> Result<~RtioTTY, IoError> {
-        match TtyWatcher::new(self.uv_loop(), fd, readable) {
-            Ok(tty) => Ok(~tty as ~RtioTTY),
+            -> Result<~rtio::RtioTTY, IoError> {
+        match TtyWatcher::new(self, fd, readable) {
+            Ok(tty) => Ok(~tty as ~rtio::RtioTTY),
             Err(e) => Err(uv_error_to_io_error(e))
         }
     }
 
-    fn pipe_open(&mut self, fd: c_int) -> Result<~RtioPipe, IoError> {
-        match PipeWatcher::open(self.uv_loop(), fd) {
-            Ok(s) => Ok(~s as ~RtioPipe),
+    fn pipe_open(&mut self, fd: c_int) -> Result<~rtio::RtioPipe, IoError> {
+        match PipeWatcher::open(self, fd) {
+            Ok(s) => Ok(~s as ~rtio::RtioPipe),
             Err(e) => Err(uv_error_to_io_error(e))
         }
     }
 
     fn signal(&mut self, signum: Signum, channel: SharedChan<Signum>)
-        -> Result<~RtioSignal, IoError> {
-        match SignalWatcher::new(self.uv_loop(), signum, channel) {
-            Ok(s) => Ok(s as ~RtioSignal),
+        -> Result<~rtio::RtioSignal, IoError> {
+        match SignalWatcher::new(self, signum, channel) {
+            Ok(s) => Ok(s as ~rtio::RtioSignal),
             Err(e) => Err(uv_error_to_io_error(e)),
         }
     }
diff --git a/src/librustuv/uvll.rs b/src/librustuv/uvll.rs
index dea90a40fa9..ad5fad99f20 100644
--- a/src/librustuv/uvll.rs
+++ b/src/librustuv/uvll.rs
@@ -37,7 +37,8 @@ use std::libc;
 #[cfg(test)]
 use std::libc::uintptr_t;
 
-pub use self::errors::*;
+pub use self::errors::{EACCES, ECONNREFUSED, ECONNRESET, EPIPE, ECONNABORTED,
+                       ECANCELED, EBADF, ENOTCONN, ENOENT};
 
 pub static OK: c_int = 0;
 pub static EOF: c_int = -4095;
@@ -576,6 +577,8 @@ extern {
 
     // generic uv functions
     pub fn uv_loop_delete(l: *uv_loop_t);
+    pub fn uv_ref(t: *uv_handle_t);
+    pub fn uv_unref(t: *uv_handle_t);
     pub fn uv_handle_size(ty: uv_handle_type) -> size_t;
     pub fn uv_req_size(ty: uv_req_type) -> size_t;
     pub fn uv_run(l: *uv_loop_t, mode: uv_run_mode) -> c_int;
diff --git a/src/libstd/any.rs b/src/libstd/any.rs
index 8bce687e245..45a91d01b7a 100644
--- a/src/libstd/any.rs
+++ b/src/libstd/any.rs
@@ -20,10 +20,11 @@
 
 use cast::transmute;
 use option::{Option, Some, None};
+use result::{Result, Ok, Err};
 use to_str::ToStr;
+use unstable::intrinsics::TypeId;
 use unstable::intrinsics;
 use util::Void;
-use unstable::intrinsics::TypeId;
 
 ///////////////////////////////////////////////////////////////////////////////
 // Any trait
@@ -118,13 +119,13 @@ impl<'a> AnyMutRefExt<'a> for &'a mut Any {
 /// Extension methods for a owning `Any` trait object
 pub trait AnyOwnExt {
     /// Returns the boxed value if it is of type `T`, or
-    /// `None` if it isn't.
-    fn move<T: 'static>(self) -> Option<~T>;
+    /// `Err(Self)` if it isn't.
+    fn move<T: 'static>(self) -> Result<~T, Self>;
 }
 
 impl AnyOwnExt for ~Any {
     #[inline]
-    fn move<T: 'static>(self) -> Option<~T> {
+    fn move<T: 'static>(self) -> Result<~T, ~Any> {
         if self.is::<T>() {
             unsafe {
                 // Extract the pointer to the boxed value, temporary alias with self
@@ -133,10 +134,10 @@ impl AnyOwnExt for ~Any {
                 // Prevent destructor on self being run
                 intrinsics::forget(self);
 
-                Some(ptr)
+                Ok(ptr)
             }
         } else {
-            None
+            Err(self)
         }
     }
 }
@@ -155,9 +156,8 @@ impl<'a> ToStr for &'a Any {
 
 #[cfg(test)]
 mod tests {
+    use prelude::*;
     use super::*;
-    use super::AnyRefExt;
-    use option::{Some, None};
 
     #[deriving(Eq)]
     struct Test;
@@ -384,13 +384,19 @@ mod tests {
         let a = ~8u as ~Any;
         let b = ~Test as ~Any;
 
-        assert_eq!(a.move(), Some(~8u));
-        assert_eq!(b.move(), Some(~Test));
+        match a.move::<uint>() {
+            Ok(a) => { assert_eq!(a, ~8u); }
+            Err(..) => fail!()
+        }
+        match b.move::<Test>() {
+            Ok(a) => { assert_eq!(a, ~Test); }
+            Err(..) => fail!()
+        }
 
         let a = ~8u as ~Any;
         let b = ~Test as ~Any;
 
-        assert_eq!(a.move(), None::<~Test>);
-        assert_eq!(b.move(), None::<~uint>);
+        assert!(a.move::<~Test>().is_err());
+        assert!(b.move::<~uint>().is_err());
     }
 }
diff --git a/src/libstd/comm/imp.rs b/src/libstd/comm/imp.rs
deleted file mode 100644
index bd1d6fed901..00000000000
--- a/src/libstd/comm/imp.rs
+++ /dev/null
@@ -1,337 +0,0 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! One of the major goals behind this channel implementation is to work
-//! seamlessly on and off the runtime. This also means that the code isn't
-//! littered with "if is_green() { ... } else { ... }". Right now, the rest of
-//! the runtime isn't quite ready to for this abstraction to be done very
-//! nicely, so the conditional "if green" blocks are all contained in this inner
-//! module.
-//!
-//! The goal of this module is to mirror what the runtime "should be", not the
-//! state that it is currently in today. You'll notice that there is no mention
-//! of schedulers or is_green inside any of the channel code, it is currently
-//! entirely contained in this one module.
-//!
-//! In the ideal world, nothing in this module exists and it is all implemented
-//! elsewhere in the runtime (in the proper location). All of this code is
-//! structured in order to easily refactor this to the correct location whenever
-//! we have the trait objects in place to serve as the boundary of the
-//! abstraction.
-
-use iter::{range, Iterator};
-use ops::Drop;
-use option::{Some, None, Option};
-use rt::local::Local;
-use rt::sched::{SchedHandle, Scheduler, TaskFromFriend};
-use rt::thread::Thread;
-use rt;
-use unstable::mutex::Mutex;
-use unstable::sync::UnsafeArc;
-
-// A task handle is a method of waking up a blocked task. The handle itself
-// is completely opaque and only has a wake() method defined on it. This
-// method will wake the method regardless of the context of the thread which
-// is currently calling wake().
-//
-// This abstraction should be able to be created when putting a task to
-// sleep. This should basically be a method on whatever the local Task is,
-// consuming the local Task.
-
-pub struct TaskHandle {
-    priv inner: TaskRepr
-}
-enum TaskRepr {
-    Green(rt::BlockedTask, *mut SchedHandle),
-    Native(NativeWakeupStyle),
-}
-enum NativeWakeupStyle {
-    ArcWakeup(UnsafeArc<Mutex>),    // shared mutex to synchronize on
-    LocalWakeup(*mut Mutex),        // synchronize on the task-local mutex
-}
-
-impl TaskHandle {
-    // Signal that this handle should be woken up. The `can_resched`
-    // argument indicates whether the current task could possibly be
-    // rescheduled or not. This does not have a lot of meaning for the
-    // native case, but for an M:N case it indicates whether a context
-    // switch can happen or not.
-    pub fn wake(self, can_resched: bool) {
-        match self.inner {
-            Green(task, handle) => {
-                // If we have a local scheduler, then use that to run the
-                // blocked task, otherwise we can use the handle to send the
-                // task back to its home.
-                if rt::in_green_task_context() {
-                    if can_resched {
-                        task.wake().map(Scheduler::run_task);
-                    } else {
-                        let mut s: ~Scheduler = Local::take();
-                        s.enqueue_blocked_task(task);
-                        Local::put(s);
-                    }
-                } else {
-                    let task = match task.wake() {
-                        Some(task) => task, None => return
-                    };
-                    // XXX: this is not an easy section of code to refactor.
-                    //      If this handle is owned by the Task (which it
-                    //      should be), then this would be a use-after-free
-                    //      because once the task is pushed onto the message
-                    //      queue, the handle is gone.
-                    //
-                    //      Currently the handle is instead owned by the
-                    //      Port/Chan pair, which means that because a
-                    //      channel is invoking this method the handle will
-                    //      continue to stay alive for the entire duration
-                    //      of this method. This will require thought when
-                    //      moving the handle into the task.
-                    unsafe { (*handle).send(TaskFromFriend(task)) }
-                }
-            }
-
-            // Note that there are no use-after-free races in this code. In
-            // the arc-case, we own the lock, and in the local case, we're
-            // using a lock so it's guranteed that they aren't running while
-            // we hold the lock.
-            Native(ArcWakeup(lock)) => {
-                unsafe {
-                    let lock = lock.get();
-                    (*lock).lock();
-                    (*lock).signal();
-                    (*lock).unlock();
-                }
-            }
-            Native(LocalWakeup(lock)) => {
-                unsafe {
-                    (*lock).lock();
-                    (*lock).signal();
-                    (*lock).unlock();
-                }
-            }
-        }
-    }
-
-    // Trashes handle to this task. This ensures that necessary memory is
-    // deallocated, and there may be some extra assertions as well.
-    pub fn trash(self) {
-        match self.inner {
-            Green(task, _) => task.assert_already_awake(),
-            Native(..) => {}
-        }
-    }
-}
-
-// This structure is an abstraction of what should be stored in the local
-// task itself. This data is currently stored inside of each channel, but
-// this should rather be stored in each task (and channels will still
-// continue to lazily initialize this data).
-
-pub struct TaskData {
-    priv handle: Option<SchedHandle>,
-    priv lock: Mutex,
-}
-
-impl TaskData {
-    pub fn new() -> TaskData {
-        TaskData {
-            handle: None,
-            lock: unsafe { Mutex::empty() },
-        }
-    }
-}
-
-impl Drop for TaskData {
-    fn drop(&mut self) {
-        unsafe { self.lock.destroy() }
-    }
-}
-
-// Now this is the really fun part. This is where all the M:N/1:1-agnostic
-// along with recv/select-agnostic blocking information goes. A "blocking
-// context" is really just a stack-allocated structure (which is probably
-// fine to be a stack-trait-object).
-//
-// This has some particularly strange interfaces, but the reason for all
-// this is to support selection/recv/1:1/M:N all in one bundle.
-
-pub struct BlockingContext<'a> {
-    priv inner: BlockingRepr<'a>
-}
-
-enum BlockingRepr<'a> {
-    GreenBlock(rt::BlockedTask, &'a mut Scheduler),
-    NativeBlock(Option<UnsafeArc<Mutex>>),
-}
-
-impl<'a> BlockingContext<'a> {
-    // Creates one blocking context. The data provided should in theory be
-    // acquired from the local task, but it is instead acquired from the
-    // channel currently.
-    //
-    // This function will call `f` with a blocking context, plus the data
-    // that it is given. This function will then return whether this task
-    // should actually go to sleep or not. If `true` is returned, then this
-    // function does not return until someone calls `wake()` on the task.
-    // If `false` is returned, then this function immediately returns.
-    //
-    // # Safety note
-    //
-    // Note that this stack closure may not be run on the same stack as when
-    // this function was called. This means that the environment of this
-    // stack closure could be unsafely aliased. This is currently prevented
-    // through the guarantee that this function will never return before `f`
-    // finishes executing.
-    pub fn one(data: &mut TaskData,
-               f: |BlockingContext, &mut TaskData| -> bool) {
-        if rt::in_green_task_context() {
-            let sched: ~Scheduler = Local::take();
-            sched.deschedule_running_task_and_then(|sched, task| {
-                let ctx = BlockingContext { inner: GreenBlock(task, sched) };
-                // no need to do something on success/failure other than
-                // returning because the `block` function for a BlockingContext
-                // takes care of reawakening itself if the blocking procedure
-                // fails. If this function is successful, then we're already
-                // blocked, and if it fails, the task will already be
-                // rescheduled.
-                f(ctx, data);
-            });
-        } else {
-            unsafe { data.lock.lock(); }
-            let ctx = BlockingContext { inner: NativeBlock(None) };
-            if f(ctx, data) {
-                unsafe { data.lock.wait(); }
-            }
-            unsafe { data.lock.unlock(); }
-        }
-    }
-
-    // Creates many blocking contexts. The intended use case for this
-    // function is selection over a number of ports. This will create `amt`
-    // blocking contexts, yielding them to `f` in turn. If `f` returns
-    // false, then this function aborts and returns immediately. If `f`
-    // repeatedly returns `true` `amt` times, then this function will block.
-    pub fn many(amt: uint, f: |BlockingContext| -> bool) {
-        if rt::in_green_task_context() {
-            let sched: ~Scheduler = Local::take();
-            sched.deschedule_running_task_and_then(|sched, task| {
-                for handle in task.make_selectable(amt) {
-                    let ctx = BlockingContext {
-                        inner: GreenBlock(handle, sched)
-                    };
-                    // see comment above in `one` for why no further action is
-                    // necessary here
-                    if !f(ctx) { break }
-                }
-            });
-        } else {
-            // In the native case, our decision to block must be shared
-            // amongst all of the channels. It may be possible to
-            // stack-allocate this mutex (instead of putting it in an
-            // UnsafeArc box), but for now in order to prevent
-            // use-after-free trivially we place this into a box and then
-            // pass that around.
-            unsafe {
-                let mtx = UnsafeArc::new(Mutex::new());
-                (*mtx.get()).lock();
-                let success = range(0, amt).all(|_| {
-                    f(BlockingContext {
-                        inner: NativeBlock(Some(mtx.clone()))
-                    })
-                });
-                if success {
-                    (*mtx.get()).wait();
-                }
-                (*mtx.get()).unlock();
-            }
-        }
-    }
-
-    // This function will consume this BlockingContext, and optionally block
-    // if according to the atomic `decision` function. The semantics of this
-    // functions are:
-    //
-    //  * `slot` is required to be a `None`-slot (which is owned by the
-    //    channel)
-    //  * The `slot` will be filled in with a blocked version of the current
-    //    task (with `wake`-ability if this function is successful).
-    //  * If the `decision` function returns true, then this function
-    //    immediately returns having relinquished ownership of the task.
-    //  * If the `decision` function returns false, then the `slot` is reset
-    //    to `None` and the task is re-scheduled if necessary (remember that
-    //    the task will not resume executing before the outer `one` or
-    //    `many` function has returned. This function is expected to have a
-    //    release memory fence in order for the modifications of `to_wake` to be
-    //    visible to other tasks. Code which attempts to read `to_wake` should
-    //    have an acquiring memory fence to guarantee that this write is
-    //    visible.
-    //
-    // This function will return whether the blocking occurred or not.
-    pub fn block(self,
-                 data: &mut TaskData,
-                 slot: &mut Option<TaskHandle>,
-                 decision: || -> bool) -> bool {
-        assert!(slot.is_none());
-        match self.inner {
-            GreenBlock(task, sched) => {
-                if data.handle.is_none() {
-                    data.handle = Some(sched.make_handle());
-                }
-                let handle = data.handle.get_mut_ref() as *mut SchedHandle;
-                *slot = Some(TaskHandle { inner: Green(task, handle) });
-
-                if !decision() {
-                    match slot.take_unwrap().inner {
-                        Green(task, _) => sched.enqueue_blocked_task(task),
-                        Native(..) => unreachable!()
-                    }
-                    false
-                } else {
-                    true
-                }
-            }
-            NativeBlock(shared) => {
-                *slot = Some(TaskHandle {
-                    inner: Native(match shared {
-                        Some(arc) => ArcWakeup(arc),
-                        None => LocalWakeup(&mut data.lock as *mut Mutex),
-                    })
-                });
-
-                if !decision() {
-                    *slot = None;
-                    false
-                } else {
-                    true
-                }
-            }
-        }
-    }
-}
-
-// Agnostic method of forcing a yield of the current task
-pub fn yield_now() {
-    if rt::in_green_task_context() {
-        let sched: ~Scheduler = Local::take();
-        sched.yield_now();
-    } else {
-        Thread::yield_now();
-    }
-}
-
-// Agnostic method of "maybe yielding" in order to provide fairness
-pub fn maybe_yield() {
-    if rt::in_green_task_context() {
-        let sched: ~Scheduler = Local::take();
-        sched.maybe_yield();
-    } else {
-        // the OS decides fairness, nothing for us to do.
-    }
-}
diff --git a/src/libstd/comm/mod.rs b/src/libstd/comm/mod.rs
index 33d5d48ebdc..21db234122b 100644
--- a/src/libstd/comm/mod.rs
+++ b/src/libstd/comm/mod.rs
@@ -233,14 +233,16 @@ use iter::Iterator;
 use kinds::Send;
 use ops::Drop;
 use option::{Option, Some, None};
+use result::{Ok, Err};
+use rt::local::Local;
+use rt::task::{Task, BlockedTask};
 use rt::thread::Thread;
-use unstable::atomics::{AtomicInt, AtomicBool, SeqCst, Relaxed};
+use sync::atomics::{AtomicInt, AtomicBool, SeqCst, Relaxed};
 use vec::{ImmutableVector, OwnedVector};
 
-use spsc = rt::spsc_queue;
-use mpsc = rt::mpsc_queue;
+use spsc = sync::spsc_queue;
+use mpsc = sync::mpsc_queue;
 
-use self::imp::{TaskHandle, TaskData, BlockingContext};
 pub use self::select::Select;
 
 macro_rules! test (
@@ -248,24 +250,26 @@ macro_rules! test (
         mod $name {
             #[allow(unused_imports)];
 
-            use util;
-            use super::super::*;
+            use native;
             use prelude::*;
+            use super::*;
+            use super::super::*;
+            use task;
+            use util;
 
             fn f() $b
 
             $($a)* #[test] fn uv() { f() }
-            $($a)* #[test]
-            #[ignore(cfg(windows))] // FIXME(#11003)
-            fn native() {
-                use unstable::run_in_bare_thread;
-                run_in_bare_thread(f);
+            $($a)* #[test] fn native() {
+                use native;
+                let (p, c) = Chan::new();
+                do native::task::spawn { c.send(f()) }
+                p.recv();
             }
         }
     )
 )
 
-mod imp;
 mod select;
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -326,9 +330,7 @@ pub struct SharedChan<T> {
 struct Packet {
     cnt: AtomicInt, // How many items are on this channel
     steals: int,    // How many times has a port received without blocking?
-    to_wake: Option<TaskHandle>, // Task to wake up
-
-    data: TaskData,
+    to_wake: Option<BlockedTask>, // Task to wake up
 
     // This lock is used to wake up native threads blocked in select. The
     // `lock` field is not used because the thread blocking in select must
@@ -343,6 +345,7 @@ struct Packet {
     selection_id: uint,
     select_next: *mut Packet,
     select_prev: *mut Packet,
+    recv_cnt: int,
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -358,13 +361,13 @@ impl Packet {
             cnt: AtomicInt::new(0),
             steals: 0,
             to_wake: None,
-            data: TaskData::new(),
             channels: AtomicInt::new(1),
 
             selecting: AtomicBool::new(false),
             selection_id: 0,
             select_next: 0 as *mut Packet,
             select_prev: 0 as *mut Packet,
+            recv_cnt: 0,
         }
     }
 
@@ -418,7 +421,10 @@ impl Packet {
     // This function must have had at least an acquire fence before it to be
     // properly called.
     fn wakeup(&mut self, can_resched: bool) {
-        self.to_wake.take_unwrap().wake(can_resched);
+        match self.to_wake.take_unwrap().wake() {
+            Some(task) => task.reawaken(can_resched),
+            None => {}
+        }
         self.selecting.store(false, Relaxed);
     }
 
@@ -490,7 +496,7 @@ impl Packet {
         match self.channels.fetch_sub(1, SeqCst) {
             1 => {
                 match self.cnt.swap(DISCONNECTED, SeqCst) {
-                    -1 => { self.wakeup(false); }
+                    -1 => { self.wakeup(true); }
                     DISCONNECTED => {}
                     n => { assert!(n >= 0); }
                 }
@@ -531,9 +537,6 @@ impl<T: Send> Chan<T> {
     /// port.
     ///
     /// Rust channels are infinitely buffered so this method will never block.
-    /// This method may trigger a rescheduling, however, in order to wake up a
-    /// blocked receiver (if one is present). If no scheduling is desired, then
-    /// the `send_deferred` guarantees that there will be no reschedulings.
     ///
     /// # Failure
     ///
@@ -555,15 +558,6 @@ impl<T: Send> Chan<T> {
         }
     }
 
-    /// This function is equivalent in the semantics of `send`, but it
-    /// guarantees that a rescheduling will never occur when this method is
-    /// called.
-    pub fn send_deferred(&self, t: T) {
-        if !self.try_send_deferred(t) {
-            fail!("sending on a closed channel");
-        }
-    }
-
     /// Attempts to send a value on this channel, returning whether it was
     /// successfully sent.
     ///
@@ -579,9 +573,8 @@ impl<T: Send> Chan<T> {
     /// be tolerated, then this method should be used instead.
     pub fn try_send(&self, t: T) -> bool { self.try(t, true) }
 
-    /// This function is equivalent in the semantics of `try_send`, but it
-    /// guarantees that a rescheduling will never occur when this method is
-    /// called.
+    /// This function will not stick around for very long. The purpose of this
+    /// function is to guarantee that no rescheduling is performed.
     pub fn try_send_deferred(&self, t: T) -> bool { self.try(t, false) }
 
     fn try(&self, t: T, can_resched: bool) -> bool {
@@ -606,8 +599,9 @@ impl<T: Send> Chan<T> {
                 // the TLS overhead can be a bit much.
                 n => {
                     assert!(n >= 0);
-                    if can_resched && n > 0 && n % RESCHED_FREQ == 0 {
-                        imp::maybe_yield();
+                    if n > 0 && n % RESCHED_FREQ == 0 {
+                        let task: ~Task = Local::take();
+                        task.maybe_yield();
                     }
                     true
                 }
@@ -642,25 +636,9 @@ impl<T: Send> SharedChan<T> {
         }
     }
 
-    /// This function is equivalent in the semantics of `send`, but it
-    /// guarantees that a rescheduling will never occur when this method is
-    /// called.
-    pub fn send_deferred(&self, t: T) {
-        if !self.try_send_deferred(t) {
-            fail!("sending on a closed channel");
-        }
-    }
-
     /// Equivalent method to `try_send` on the `Chan` type (using the same
     /// semantics)
-    pub fn try_send(&self, t: T) -> bool { self.try(t, true) }
-
-    /// This function is equivalent in the semantics of `try_send`, but it
-    /// guarantees that a rescheduling will never occur when this method is
-    /// called.
-    pub fn try_send_deferred(&self, t: T) -> bool { self.try(t, false) }
-
-    fn try(&self, t: T, can_resched: bool) -> bool {
+    pub fn try_send(&self, t: T) -> bool {
         unsafe {
             // Note that the multiple sender case is a little tricker
             // semantically than the single sender case. The logic for
@@ -697,10 +675,11 @@ impl<T: Send> SharedChan<T> {
 
             match (*packet).increment() {
                 DISCONNECTED => {} // oh well, we tried
-                -1 => { (*packet).wakeup(can_resched); }
+                -1 => { (*packet).wakeup(true); }
                 n => {
-                    if can_resched && n > 0 && n % RESCHED_FREQ == 0 {
-                        imp::maybe_yield();
+                    if n > 0 && n % RESCHED_FREQ == 0 {
+                        let task: ~Task = Local::take();
+                        task.maybe_yield();
                     }
                 }
             }
@@ -768,6 +747,18 @@ impl<T: Send> Port<T> {
         // This is a "best effort" situation, so if a queue is inconsistent just
         // don't worry about it.
         let this = unsafe { cast::transmute_mut(self) };
+
+        // See the comment about yielding on sends, but the same applies here.
+        // If a thread is spinning in try_recv we should try
+        unsafe {
+            let packet = this.queue.packet();
+            (*packet).recv_cnt += 1;
+            if (*packet).recv_cnt % RESCHED_FREQ == 0 {
+                let task: ~Task = Local::take();
+                task.maybe_yield();
+            }
+        }
+
         let ret = match this.queue {
             SPSC(ref mut queue) => queue.pop(),
             MPSC(ref mut queue) => match queue.pop() {
@@ -840,15 +831,22 @@ impl<T: Send> Port<T> {
         unsafe {
             this = cast::transmute_mut(self);
             packet = this.queue.packet();
-            BlockingContext::one(&mut (*packet).data, |ctx, data| {
-                ctx.block(data, &mut (*packet).to_wake, || (*packet).decrement())
+            let task: ~Task = Local::take();
+            task.deschedule(1, |task| {
+                assert!((*packet).to_wake.is_none());
+                (*packet).to_wake = Some(task);
+                if (*packet).decrement() {
+                    Ok(())
+                } else {
+                    Err((*packet).to_wake.take_unwrap())
+                }
             });
         }
 
         let data = self.try_recv_inc(false);
         if data.is_none() &&
            unsafe { (*packet).cnt.load(SeqCst) } != DISCONNECTED {
-            fail!("bug: woke up too soon");
+            fail!("bug: woke up too soon {}", unsafe { (*packet).cnt.load(SeqCst) });
         }
         return data;
     }
@@ -880,10 +878,16 @@ impl<T: Send> Drop for Port<T> {
 mod test {
     use prelude::*;
 
-    use task;
-    use rt::thread::Thread;
+    use native;
+    use os;
     use super::*;
-    use rt::test::*;
+
+    pub fn stress_factor() -> uint {
+        match os::getenv("RUST_TEST_STRESS") {
+            Some(val) => from_str::<uint>(val).unwrap(),
+            None => 1,
+        }
+    }
 
     test!(fn smoke() {
         let (p, c) = Chan::new();
@@ -910,99 +914,88 @@ mod test {
         assert_eq!(p.recv(), 1);
     })
 
-    #[test]
-    fn smoke_threads() {
+    test!(fn smoke_threads() {
         let (p, c) = Chan::new();
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             c.send(1);
         }
         assert_eq!(p.recv(), 1);
-    }
+    })
 
-    #[test] #[should_fail]
-    fn smoke_port_gone() {
+    test!(fn smoke_port_gone() {
         let (p, c) = Chan::new();
         drop(p);
         c.send(1);
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn smoke_shared_port_gone() {
+    test!(fn smoke_shared_port_gone() {
         let (p, c) = SharedChan::new();
         drop(p);
         c.send(1);
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn smoke_shared_port_gone2() {
+    test!(fn smoke_shared_port_gone2() {
         let (p, c) = SharedChan::new();
         drop(p);
         let c2 = c.clone();
         drop(c);
         c2.send(1);
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn port_gone_concurrent() {
+    test!(fn port_gone_concurrent() {
         let (p, c) = Chan::new();
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             p.recv();
         }
         loop { c.send(1) }
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn port_gone_concurrent_shared() {
+    test!(fn port_gone_concurrent_shared() {
         let (p, c) = SharedChan::new();
         let c1 = c.clone();
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             p.recv();
         }
         loop {
             c.send(1);
             c1.send(1);
         }
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn smoke_chan_gone() {
+    test!(fn smoke_chan_gone() {
         let (p, c) = Chan::<int>::new();
         drop(c);
         p.recv();
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn smoke_chan_gone_shared() {
+    test!(fn smoke_chan_gone_shared() {
         let (p, c) = SharedChan::<()>::new();
         let c2 = c.clone();
         drop(c);
         drop(c2);
         p.recv();
-    }
+    } #[should_fail])
 
-    #[test] #[should_fail]
-    fn chan_gone_concurrent() {
+    test!(fn chan_gone_concurrent() {
         let (p, c) = Chan::new();
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             c.send(1);
             c.send(1);
         }
         loop { p.recv(); }
-    }
+    } #[should_fail])
 
-    #[test]
-    fn stress() {
+    test!(fn stress() {
         let (p, c) = Chan::new();
-        do task::spawn_sched(task::SingleThreaded) {
+        do spawn {
             for _ in range(0, 10000) { c.send(1); }
         }
         for _ in range(0, 10000) {
             assert_eq!(p.recv(), 1);
         }
-    }
+    })
 
-    #[test]
-    fn stress_shared() {
+    test!(fn stress_shared() {
         static AMT: uint = 10000;
         static NTHREADS: uint = 8;
         let (p, c) = SharedChan::<int>::new();
@@ -1018,47 +1011,53 @@ mod test {
 
         for _ in range(0, NTHREADS) {
             let c = c.clone();
-            do task::spawn_sched(task::SingleThreaded) {
+            do spawn {
                 for _ in range(0, AMT) { c.send(1); }
             }
         }
         p1.recv();
-
-    }
+    })
 
     #[test]
     #[ignore(cfg(windows))] // FIXME(#11003)
     fn send_from_outside_runtime() {
         let (p, c) = Chan::<int>::new();
         let (p1, c1) = Chan::new();
+        let (port, chan) = SharedChan::new();
+        let chan2 = chan.clone();
         do spawn {
             c1.send(());
             for _ in range(0, 40) {
                 assert_eq!(p.recv(), 1);
             }
+            chan2.send(());
         }
         p1.recv();
-        let t = do Thread::start {
+        do native::task::spawn {
             for _ in range(0, 40) {
                 c.send(1);
             }
-        };
-        t.join();
+            chan.send(());
+        }
+        port.recv();
+        port.recv();
     }
 
     #[test]
     #[ignore(cfg(windows))] // FIXME(#11003)
     fn recv_from_outside_runtime() {
         let (p, c) = Chan::<int>::new();
-        let t = do Thread::start {
+        let (dp, dc) = Chan::new();
+        do native::task::spawn {
             for _ in range(0, 40) {
                 assert_eq!(p.recv(), 1);
             }
+            dc.send(());
         };
         for _ in range(0, 40) {
             c.send(1);
         }
-        t.join();
+        dp.recv();
     }
 
     #[test]
@@ -1066,173 +1065,132 @@ mod test {
     fn no_runtime() {
         let (p1, c1) = Chan::<int>::new();
         let (p2, c2) = Chan::<int>::new();
-        let t1 = do Thread::start {
+        let (port, chan) = SharedChan::new();
+        let chan2 = chan.clone();
+        do native::task::spawn {
             assert_eq!(p1.recv(), 1);
             c2.send(2);
-        };
-        let t2 = do Thread::start {
+            chan2.send(());
+        }
+        do native::task::spawn {
             c1.send(1);
             assert_eq!(p2.recv(), 2);
-        };
-        t1.join();
-        t2.join();
-    }
-
-    #[test]
-    fn oneshot_single_thread_close_port_first() {
-        // Simple test of closing without sending
-        do run_in_newsched_task {
-            let (port, _chan) = Chan::<int>::new();
-            { let _p = port; }
+            chan.send(());
         }
+        port.recv();
+        port.recv();
     }
 
-    #[test]
-    fn oneshot_single_thread_close_chan_first() {
+    test!(fn oneshot_single_thread_close_port_first() {
         // Simple test of closing without sending
-        do run_in_newsched_task {
-            let (_port, chan) = Chan::<int>::new();
-            { let _c = chan; }
-        }
-    }
+        let (port, _chan) = Chan::<int>::new();
+        { let _p = port; }
+    })
 
-    #[test] #[should_fail]
-    fn oneshot_single_thread_send_port_close() {
+    test!(fn oneshot_single_thread_close_chan_first() {
+        // Simple test of closing without sending
+        let (_port, chan) = Chan::<int>::new();
+        { let _c = chan; }
+    })
+
+    test!(fn oneshot_single_thread_send_port_close() {
         // Testing that the sender cleans up the payload if receiver is closed
         let (port, chan) = Chan::<~int>::new();
         { let _p = port; }
         chan.send(~0);
-    }
+    } #[should_fail])
 
-    #[test]
-    fn oneshot_single_thread_recv_chan_close() {
+    test!(fn oneshot_single_thread_recv_chan_close() {
         // Receiving on a closed chan will fail
-        do run_in_newsched_task {
-            let res = do spawntask_try {
-                let (port, chan) = Chan::<~int>::new();
-                { let _c = chan; }
-                port.recv();
-            };
-            // What is our res?
-            assert!(res.is_err());
-        }
-    }
-
-    #[test]
-    fn oneshot_single_thread_send_then_recv() {
-        do run_in_newsched_task {
+        let res = do task::try {
             let (port, chan) = Chan::<~int>::new();
-            chan.send(~10);
+            { let _c = chan; }
+            port.recv();
+        };
+        // What is our res?
+        assert!(res.is_err());
+    })
+
+    test!(fn oneshot_single_thread_send_then_recv() {
+        let (port, chan) = Chan::<~int>::new();
+        chan.send(~10);
+        assert!(port.recv() == ~10);
+    })
+
+    test!(fn oneshot_single_thread_try_send_open() {
+        let (port, chan) = Chan::<int>::new();
+        assert!(chan.try_send(10));
+        assert!(port.recv() == 10);
+    })
+
+    test!(fn oneshot_single_thread_try_send_closed() {
+        let (port, chan) = Chan::<int>::new();
+        { let _p = port; }
+        assert!(!chan.try_send(10));
+    })
+
+    test!(fn oneshot_single_thread_try_recv_open() {
+        let (port, chan) = Chan::<int>::new();
+        chan.send(10);
+        assert!(port.try_recv() == Some(10));
+    })
+
+    test!(fn oneshot_single_thread_try_recv_closed() {
+        let (port, chan) = Chan::<int>::new();
+        { let _c = chan; }
+        assert!(port.recv_opt() == None);
+    })
+
+    test!(fn oneshot_single_thread_peek_data() {
+        let (port, chan) = Chan::<int>::new();
+        assert!(port.try_recv().is_none());
+        chan.send(10);
+        assert!(port.try_recv().is_some());
+    })
+
+    test!(fn oneshot_single_thread_peek_close() {
+        let (port, chan) = Chan::<int>::new();
+        { let _c = chan; }
+        assert!(port.try_recv().is_none());
+        assert!(port.try_recv().is_none());
+    })
+
+    test!(fn oneshot_single_thread_peek_open() {
+        let (port, _) = Chan::<int>::new();
+        assert!(port.try_recv().is_none());
+    })
+
+    test!(fn oneshot_multi_task_recv_then_send() {
+        let (port, chan) = Chan::<~int>::new();
+        do spawn {
             assert!(port.recv() == ~10);
         }
-    }
 
-    #[test]
-    fn oneshot_single_thread_try_send_open() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<int>::new();
-            assert!(chan.try_send(10));
-            assert!(port.recv() == 10);
+        chan.send(~10);
+    })
+
+    test!(fn oneshot_multi_task_recv_then_close() {
+        let (port, chan) = Chan::<~int>::new();
+        do spawn {
+            let _chan = chan;
         }
-    }
+        let res = do task::try {
+            assert!(port.recv() == ~10);
+        };
+        assert!(res.is_err());
+    })
 
-    #[test]
-    fn oneshot_single_thread_try_send_closed() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<int>::new();
-            { let _p = port; }
-            assert!(!chan.try_send(10));
-        }
-    }
-
-    #[test]
-    fn oneshot_single_thread_try_recv_open() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<int>::new();
-            chan.send(10);
-            assert!(port.try_recv() == Some(10));
-        }
-    }
-
-    #[test]
-    fn oneshot_single_thread_try_recv_closed() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<int>::new();
-            { let _c = chan; }
-            assert!(port.recv_opt() == None);
-        }
-    }
-
-    #[test]
-    fn oneshot_single_thread_peek_data() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<int>::new();
-            assert!(port.try_recv().is_none());
-            chan.send(10);
-            assert!(port.try_recv().is_some());
-        }
-    }
-
-    #[test]
-    fn oneshot_single_thread_peek_close() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<int>::new();
-            { let _c = chan; }
-            assert!(port.try_recv().is_none());
-            assert!(port.try_recv().is_none());
-        }
-    }
-
-    #[test]
-    fn oneshot_single_thread_peek_open() {
-        do run_in_newsched_task {
-            let (port, _) = Chan::<int>::new();
-            assert!(port.try_recv().is_none());
-        }
-    }
-
-    #[test]
-    fn oneshot_multi_task_recv_then_send() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<~int>::new();
-            do spawntask {
-                assert!(port.recv() == ~10);
-            }
-
-            chan.send(~10);
-        }
-    }
-
-    #[test]
-    fn oneshot_multi_task_recv_then_close() {
-        do run_in_newsched_task {
-            let (port, chan) = Chan::<~int>::new();
-            do spawntask_later {
-                let _chan = chan;
-            }
-            let res = do spawntask_try {
-                assert!(port.recv() == ~10);
-            };
-            assert!(res.is_err());
-        }
-    }
-
-    #[test]
-    fn oneshot_multi_thread_close_stress() {
+    test!(fn oneshot_multi_thread_close_stress() {
         stress_factor().times(|| {
-            do run_in_newsched_task {
-                let (port, chan) = Chan::<int>::new();
-                let thread = do spawntask_thread {
-                    let _p = port;
-                };
-                let _chan = chan;
-                thread.join();
+            let (port, chan) = Chan::<int>::new();
+            do spawn {
+                let _p = port;
             }
+            let _chan = chan;
         })
-    }
+    })
 
-    #[test]
-    fn oneshot_multi_thread_send_close_stress() {
+    test!(fn oneshot_multi_thread_send_close_stress() {
         stress_factor().times(|| {
             let (port, chan) = Chan::<int>::new();
             do spawn {
@@ -1242,10 +1200,9 @@ mod test {
                 chan.send(1);
             };
         })
-    }
+    })
 
-    #[test]
-    fn oneshot_multi_thread_recv_close_stress() {
+    test!(fn oneshot_multi_thread_recv_close_stress() {
         stress_factor().times(|| {
             let (port, chan) = Chan::<int>::new();
             do spawn {
@@ -1262,10 +1219,9 @@ mod test {
                 }
             };
         })
-    }
+    })
 
-    #[test]
-    fn oneshot_multi_thread_send_recv_stress() {
+    test!(fn oneshot_multi_thread_send_recv_stress() {
         stress_factor().times(|| {
             let (port, chan) = Chan::<~int>::new();
             do spawn {
@@ -1275,10 +1231,9 @@ mod test {
                 assert!(port.recv() == ~10);
             }
         })
-    }
+    })
 
-    #[test]
-    fn stream_send_recv_stress() {
+    test!(fn stream_send_recv_stress() {
         stress_factor().times(|| {
             let (port, chan) = Chan::<~int>::new();
 
@@ -1288,7 +1243,7 @@ mod test {
             fn send(chan: Chan<~int>, i: int) {
                 if i == 10 { return }
 
-                do spawntask_random {
+                do spawn {
                     chan.send(~i);
                     send(chan, i + 1);
                 }
@@ -1297,44 +1252,37 @@ mod test {
             fn recv(port: Port<~int>, i: int) {
                 if i == 10 { return }
 
-                do spawntask_random {
+                do spawn {
                     assert!(port.recv() == ~i);
                     recv(port, i + 1);
                 };
             }
         })
-    }
+    })
 
-    #[test]
-    fn recv_a_lot() {
+    test!(fn recv_a_lot() {
         // Regression test that we don't run out of stack in scheduler context
-        do run_in_newsched_task {
-            let (port, chan) = Chan::new();
-            10000.times(|| { chan.send(()) });
-            10000.times(|| { port.recv() });
-        }
-    }
+        let (port, chan) = Chan::new();
+        10000.times(|| { chan.send(()) });
+        10000.times(|| { port.recv() });
+    })
 
-    #[test]
-    fn shared_chan_stress() {
-        do run_in_mt_newsched_task {
-            let (port, chan) = SharedChan::new();
-            let total = stress_factor() + 100;
-            total.times(|| {
-                let chan_clone = chan.clone();
-                do spawntask_random {
-                    chan_clone.send(());
-                }
-            });
+    test!(fn shared_chan_stress() {
+        let (port, chan) = SharedChan::new();
+        let total = stress_factor() + 100;
+        total.times(|| {
+            let chan_clone = chan.clone();
+            do spawn {
+                chan_clone.send(());
+            }
+        });
 
-            total.times(|| {
-                port.recv();
-            });
-        }
-    }
+        total.times(|| {
+            port.recv();
+        });
+    })
 
-    #[test]
-    fn test_nested_recv_iter() {
+    test!(fn test_nested_recv_iter() {
         let (port, chan) = Chan::<int>::new();
         let (total_port, total_chan) = Chan::<int>::new();
 
@@ -1351,10 +1299,9 @@ mod test {
         chan.send(2);
         drop(chan);
         assert_eq!(total_port.recv(), 6);
-    }
+    })
 
-    #[test]
-    fn test_recv_iter_break() {
+    test!(fn test_recv_iter_break() {
         let (port, chan) = Chan::<int>::new();
         let (count_port, count_chan) = Chan::<int>::new();
 
@@ -1376,5 +1323,5 @@ mod test {
         chan.try_send(2);
         drop(chan);
         assert_eq!(count_port.recv(), 4);
-    }
+    })
 }
diff --git a/src/libstd/comm/select.rs b/src/libstd/comm/select.rs
index bbd4cfea78d..302c9d9ea46 100644
--- a/src/libstd/comm/select.rs
+++ b/src/libstd/comm/select.rs
@@ -50,10 +50,13 @@ use kinds::Send;
 use ops::Drop;
 use option::{Some, None, Option};
 use ptr::RawPtr;
-use super::imp::BlockingContext;
-use super::{Packet, Port, imp};
+use result::{Ok, Err};
+use rt::local::Local;
+use rt::task::Task;
+use super::{Packet, Port};
+use sync::atomics::{Relaxed, SeqCst};
+use task;
 use uint;
-use unstable::atomics::{Relaxed, SeqCst};
 
 macro_rules! select {
     (
@@ -184,19 +187,22 @@ impl Select {
             // Acquire a number of blocking contexts, and block on each one
             // sequentially until one fails. If one fails, then abort
             // immediately so we can go unblock on all the other ports.
-            BlockingContext::many(amt, |ctx| {
+            let task: ~Task = Local::take();
+            task.deschedule(amt, |task| {
+                // Prepare for the block
                 let (i, packet) = iter.next().unwrap();
+                assert!((*packet).to_wake.is_none());
+                (*packet).to_wake = Some(task);
                 (*packet).selecting.store(true, SeqCst);
-                if !ctx.block(&mut (*packet).data,
-                              &mut (*packet).to_wake,
-                              || (*packet).decrement()) {
+
+                if (*packet).decrement() {
+                    Ok(())
+                } else {
                     (*packet).abort_selection(false);
                     (*packet).selecting.store(false, SeqCst);
                     ready_index = i;
                     ready_id = (*packet).selection_id;
-                    false
-                } else {
-                    true
+                    Err((*packet).to_wake.take_unwrap())
                 }
             });
 
@@ -225,7 +231,7 @@ impl Select {
                 if (*packet).abort_selection(true) {
                     ready_id = (*packet).selection_id;
                     while (*packet).selecting.load(Relaxed) {
-                        imp::yield_now();
+                        task::deschedule();
                     }
                 }
             }
@@ -304,6 +310,7 @@ impl Iterator<*mut Packet> for PacketIterator {
 }
 
 #[cfg(test)]
+#[allow(unused_imports)]
 mod test {
     use super::super::*;
     use prelude::*;
@@ -359,19 +366,16 @@ mod test {
         )
     })
 
-    #[test]
-    fn unblocks() {
-        use std::io::timer;
-
+    test!(fn unblocks() {
         let (mut p1, c1) = Chan::<int>::new();
         let (mut p2, _c2) = Chan::<int>::new();
         let (p3, c3) = Chan::<int>::new();
 
         do spawn {
-            timer::sleep(3);
+            20.times(task::deschedule);
             c1.send(1);
             p3.recv();
-            timer::sleep(3);
+            20.times(task::deschedule);
         }
 
         select! (
@@ -383,18 +387,15 @@ mod test {
             a = p1.recv_opt() => { assert_eq!(a, None); },
             _b = p2.recv() => { fail!() }
         )
-    }
-
-    #[test]
-    fn both_ready() {
-        use std::io::timer;
+    })
 
+    test!(fn both_ready() {
         let (mut p1, c1) = Chan::<int>::new();
         let (mut p2, c2) = Chan::<int>::new();
         let (p3, c3) = Chan::<()>::new();
 
         do spawn {
-            timer::sleep(3);
+            20.times(task::deschedule);
             c1.send(1);
             c2.send(2);
             p3.recv();
@@ -408,11 +409,12 @@ mod test {
             a = p1.recv() => { assert_eq!(a, 1); },
             a = p2.recv() => { assert_eq!(a, 2); }
         )
+        assert_eq!(p1.try_recv(), None);
+        assert_eq!(p2.try_recv(), None);
         c3.send(());
-    }
+    })
 
-    #[test]
-    fn stress() {
+    test!(fn stress() {
         static AMT: int = 10000;
         let (mut p1, c1) = Chan::<int>::new();
         let (mut p2, c2) = Chan::<int>::new();
@@ -436,69 +438,5 @@ mod test {
             )
             c3.send(());
         }
-    }
-
-    #[test]
-    #[ignore(cfg(windows))] // FIXME(#11003)
-    fn stress_native() {
-        use std::rt::thread::Thread;
-        use std::unstable::run_in_bare_thread;
-        static AMT: int = 10000;
-
-        do run_in_bare_thread {
-            let (mut p1, c1) = Chan::<int>::new();
-            let (mut p2, c2) = Chan::<int>::new();
-            let (p3, c3) = Chan::<()>::new();
-
-            let t = do Thread::start {
-                for i in range(0, AMT) {
-                    if i % 2 == 0 {
-                        c1.send(i);
-                    } else {
-                        c2.send(i);
-                    }
-                    p3.recv();
-                }
-            };
-
-            for i in range(0, AMT) {
-                select! (
-                    i1 = p1.recv() => { assert!(i % 2 == 0 && i == i1); },
-                    i2 = p2.recv() => { assert!(i % 2 == 1 && i == i2); }
-                )
-                c3.send(());
-            }
-            t.join();
-        }
-    }
-
-    #[test]
-    #[ignore(cfg(windows))] // FIXME(#11003)
-    fn native_both_ready() {
-        use std::rt::thread::Thread;
-        use std::unstable::run_in_bare_thread;
-
-        do run_in_bare_thread {
-            let (mut p1, c1) = Chan::<int>::new();
-            let (mut p2, c2) = Chan::<int>::new();
-            let (p3, c3) = Chan::<()>::new();
-
-            let t = do Thread::start {
-                c1.send(1);
-                c2.send(2);
-                p3.recv();
-            };
-
-            select! (
-                a = p1.recv() => { assert_eq!(a, 1); },
-                b = p2.recv() => { assert_eq!(b, 2); }
-            )
-            select! (
-                a = p1.recv() => { assert_eq!(a, 1); },
-                b = p2.recv() => { assert_eq!(b, 2); }
-            )
-            c3.send(());
-            t.join();
-        }
-    }
+    })
 }
diff --git a/src/libstd/io/fs.rs b/src/libstd/io/fs.rs
index a1465ca7b33..b4838d534dc 100644
--- a/src/libstd/io/fs.rs
+++ b/src/libstd/io/fs.rs
@@ -54,7 +54,7 @@ use super::{SeekStyle, Read, Write, Open, IoError, Truncate,
 use rt::rtio::{RtioFileStream, IoFactory, LocalIo};
 use io;
 use option::{Some, None, Option};
-use result::{Ok, Err, Result};
+use result::{Ok, Err};
 use path;
 use path::{Path, GenericPath};
 use vec::{OwnedVector, ImmutableVector};
@@ -75,17 +75,6 @@ pub struct File {
     priv last_nread: int,
 }
 
-fn io_raise<T>(f: |io: &mut IoFactory| -> Result<T, IoError>) -> Option<T> {
-    let mut io = LocalIo::borrow();
-    match f(io.get()) {
-        Ok(t) => Some(t),
-        Err(ioerr) => {
-            io_error::cond.raise(ioerr);
-            None
-        }
-    }
-}
-
 impl File {
     /// Open a file at `path` in the mode specified by the `mode` and `access`
     /// arguments
@@ -131,18 +120,15 @@ impl File {
     pub fn open_mode(path: &Path,
                      mode: FileMode,
                      access: FileAccess) -> Option<File> {
-        let mut io = LocalIo::borrow();
-        match io.get().fs_open(&path.to_c_str(), mode, access) {
-            Ok(fd) => Some(File {
-                path: path.clone(),
-                fd: fd,
-                last_nread: -1
-            }),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| {
+            io.fs_open(&path.to_c_str(), mode, access).map(|fd| {
+                File {
+                    path: path.clone(),
+                    fd: fd,
+                    last_nread: -1
+                }
+            })
+        })
     }
 
     /// Attempts to open a file in read-only mode. This function is equivalent to
@@ -242,7 +228,7 @@ impl File {
 /// directory, the user lacks permissions to remove the file, or if some
 /// other filesystem-level error occurs.
 pub fn unlink(path: &Path) {
-    io_raise(|io| io.fs_unlink(&path.to_c_str()));
+    LocalIo::maybe_raise(|io| io.fs_unlink(&path.to_c_str()));
 }
 
 /// Given a path, query the file system to get information about a file,
@@ -270,7 +256,9 @@ pub fn unlink(path: &Path) {
 /// requisite permissions to perform a `stat` call on the given path or if
 /// there is no entry in the filesystem at the provided path.
 pub fn stat(path: &Path) -> FileStat {
-    io_raise(|io| io.fs_stat(&path.to_c_str())).unwrap_or_else(dummystat)
+    LocalIo::maybe_raise(|io| {
+        io.fs_stat(&path.to_c_str())
+    }).unwrap_or_else(dummystat)
 }
 
 fn dummystat() -> FileStat {
@@ -306,7 +294,9 @@ fn dummystat() -> FileStat {
 ///
 /// See `stat`
 pub fn lstat(path: &Path) -> FileStat {
-    io_raise(|io| io.fs_lstat(&path.to_c_str())).unwrap_or_else(dummystat)
+    LocalIo::maybe_raise(|io| {
+        io.fs_lstat(&path.to_c_str())
+    }).unwrap_or_else(dummystat)
 }
 
 /// Rename a file or directory to a new name.
@@ -324,7 +314,7 @@ pub fn lstat(path: &Path) -> FileStat {
 /// the process lacks permissions to view the contents, or if some other
 /// intermittent I/O error occurs.
 pub fn rename(from: &Path, to: &Path) {
-    io_raise(|io| io.fs_rename(&from.to_c_str(), &to.to_c_str()));
+    LocalIo::maybe_raise(|io| io.fs_rename(&from.to_c_str(), &to.to_c_str()));
 }
 
 /// Copies the contents of one file to another. This function will also
@@ -395,7 +385,7 @@ pub fn copy(from: &Path, to: &Path) {
 /// condition. Some possible error situations are not having the permission to
 /// change the attributes of a file or the file not existing.
 pub fn chmod(path: &Path, mode: io::FilePermission) {
-    io_raise(|io| io.fs_chmod(&path.to_c_str(), mode));
+    LocalIo::maybe_raise(|io| io.fs_chmod(&path.to_c_str(), mode));
 }
 
 /// Change the user and group owners of a file at the specified path.
@@ -404,7 +394,7 @@ pub fn chmod(path: &Path, mode: io::FilePermission) {
 ///
 /// This function will raise on the `io_error` condition on failure.
 pub fn chown(path: &Path, uid: int, gid: int) {
-    io_raise(|io| io.fs_chown(&path.to_c_str(), uid, gid));
+    LocalIo::maybe_raise(|io| io.fs_chown(&path.to_c_str(), uid, gid));
 }
 
 /// Creates a new hard link on the filesystem. The `dst` path will be a
@@ -415,7 +405,7 @@ pub fn chown(path: &Path, uid: int, gid: int) {
 ///
 /// This function will raise on the `io_error` condition on failure.
 pub fn link(src: &Path, dst: &Path) {
-    io_raise(|io| io.fs_link(&src.to_c_str(), &dst.to_c_str()));
+    LocalIo::maybe_raise(|io| io.fs_link(&src.to_c_str(), &dst.to_c_str()));
 }
 
 /// Creates a new symbolic link on the filesystem. The `dst` path will be a
@@ -425,7 +415,7 @@ pub fn link(src: &Path, dst: &Path) {
 ///
 /// This function will raise on the `io_error` condition on failure.
 pub fn symlink(src: &Path, dst: &Path) {
-    io_raise(|io| io.fs_symlink(&src.to_c_str(), &dst.to_c_str()));
+    LocalIo::maybe_raise(|io| io.fs_symlink(&src.to_c_str(), &dst.to_c_str()));
 }
 
 /// Reads a symlink, returning the file that the symlink points to.
@@ -436,7 +426,7 @@ pub fn symlink(src: &Path, dst: &Path) {
 /// conditions include reading a file that does not exist or reading a file
 /// which is not a symlink.
 pub fn readlink(path: &Path) -> Option<Path> {
-    io_raise(|io| io.fs_readlink(&path.to_c_str()))
+    LocalIo::maybe_raise(|io| io.fs_readlink(&path.to_c_str()))
 }
 
 /// Create a new, empty directory at the provided path
@@ -456,7 +446,7 @@ pub fn readlink(path: &Path) -> Option<Path> {
 /// to make a new directory at the provided path, or if the directory already
 /// exists.
 pub fn mkdir(path: &Path, mode: FilePermission) {
-    io_raise(|io| io.fs_mkdir(&path.to_c_str(), mode));
+    LocalIo::maybe_raise(|io| io.fs_mkdir(&path.to_c_str(), mode));
 }
 
 /// Remove an existing, empty directory
@@ -475,7 +465,7 @@ pub fn mkdir(path: &Path, mode: FilePermission) {
 /// to remove the directory at the provided path, or if the directory isn't
 /// empty.
 pub fn rmdir(path: &Path) {
-    io_raise(|io| io.fs_rmdir(&path.to_c_str()));
+    LocalIo::maybe_raise(|io| io.fs_rmdir(&path.to_c_str()));
 }
 
 /// Retrieve a vector containing all entries within a provided directory
@@ -502,7 +492,9 @@ pub fn rmdir(path: &Path) {
 /// the process lacks permissions to view the contents or if the `path` points
 /// at a non-directory file
 pub fn readdir(path: &Path) -> ~[Path] {
-    io_raise(|io| io.fs_readdir(&path.to_c_str(), 0)).unwrap_or_else(|| ~[])
+    LocalIo::maybe_raise(|io| {
+        io.fs_readdir(&path.to_c_str(), 0)
+    }).unwrap_or_else(|| ~[])
 }
 
 /// Returns an iterator which will recursively walk the directory structure
@@ -583,7 +575,7 @@ pub fn rmdir_recursive(path: &Path) {
 /// happens.
 // FIXME(#10301) these arguments should not be u64
 pub fn change_file_times(path: &Path, atime: u64, mtime: u64) {
-    io_raise(|io| io.fs_utime(&path.to_c_str(), atime, mtime));
+    LocalIo::maybe_raise(|io| io.fs_utime(&path.to_c_str(), atime, mtime));
 }
 
 impl Reader for File {
@@ -722,7 +714,7 @@ mod test {
         }
     }
 
-    fn tmpdir() -> TempDir {
+    pub fn tmpdir() -> TempDir {
         use os;
         use rand;
         let ret = os::tmpdir().join(format!("rust-{}", rand::random::<u32>()));
@@ -730,32 +722,7 @@ mod test {
         TempDir(ret)
     }
 
-    macro_rules! test (
-        { fn $name:ident() $b:block } => (
-            mod $name {
-                use prelude::*;
-                use io::{SeekSet, SeekCur, SeekEnd, io_error, Read, Open,
-                         ReadWrite};
-                use io;
-                use str;
-                use io::fs::{File, rmdir, mkdir, readdir, rmdir_recursive,
-                             mkdir_recursive, copy, unlink, stat, symlink, link,
-                             readlink, chmod, lstat, change_file_times};
-                use io::fs::test::tmpdir;
-                use util;
-
-                fn f() $b
-
-                #[test] fn uv() { f() }
-                #[test] fn native() {
-                    use rt::test::run_in_newsched_task;
-                    run_in_newsched_task(f);
-                }
-            }
-        )
-    )
-
-    test!(fn file_test_io_smoke_test() {
+    iotest!(fn file_test_io_smoke_test() {
         let message = "it's alright. have a good time";
         let tmpdir = tmpdir();
         let filename = &tmpdir.join("file_rt_io_file_test.txt");
@@ -775,7 +742,7 @@ mod test {
         unlink(filename);
     })
 
-    test!(fn invalid_path_raises() {
+    iotest!(fn invalid_path_raises() {
         let tmpdir = tmpdir();
         let filename = &tmpdir.join("file_that_does_not_exist.txt");
         let mut called = false;
@@ -788,7 +755,7 @@ mod test {
         assert!(called);
     })
 
-    test!(fn file_test_iounlinking_invalid_path_should_raise_condition() {
+    iotest!(fn file_test_iounlinking_invalid_path_should_raise_condition() {
         let tmpdir = tmpdir();
         let filename = &tmpdir.join("file_another_file_that_does_not_exist.txt");
         let mut called = false;
@@ -798,7 +765,7 @@ mod test {
         assert!(called);
     })
 
-    test!(fn file_test_io_non_positional_read() {
+    iotest!(fn file_test_io_non_positional_read() {
         let message: &str = "ten-four";
         let mut read_mem = [0, .. 8];
         let tmpdir = tmpdir();
@@ -823,7 +790,7 @@ mod test {
         assert_eq!(read_str, message);
     })
 
-    test!(fn file_test_io_seek_and_tell_smoke_test() {
+    iotest!(fn file_test_io_seek_and_tell_smoke_test() {
         let message = "ten-four";
         let mut read_mem = [0, .. 4];
         let set_cursor = 4 as u64;
@@ -849,7 +816,7 @@ mod test {
         assert_eq!(tell_pos_post_read, message.len() as u64);
     })
 
-    test!(fn file_test_io_seek_and_write() {
+    iotest!(fn file_test_io_seek_and_write() {
         let initial_msg =   "food-is-yummy";
         let overwrite_msg =    "-the-bar!!";
         let final_msg =     "foo-the-bar!!";
@@ -872,7 +839,7 @@ mod test {
         assert!(read_str == final_msg.to_owned());
     })
 
-    test!(fn file_test_io_seek_shakedown() {
+    iotest!(fn file_test_io_seek_shakedown() {
         use std::str;          // 01234567890123
         let initial_msg =   "qwer-asdf-zxcv";
         let chunk_one: &str = "qwer";
@@ -903,7 +870,7 @@ mod test {
         unlink(filename);
     })
 
-    test!(fn file_test_stat_is_correct_on_is_file() {
+    iotest!(fn file_test_stat_is_correct_on_is_file() {
         let tmpdir = tmpdir();
         let filename = &tmpdir.join("file_stat_correct_on_is_file.txt");
         {
@@ -916,7 +883,7 @@ mod test {
         unlink(filename);
     })
 
-    test!(fn file_test_stat_is_correct_on_is_dir() {
+    iotest!(fn file_test_stat_is_correct_on_is_dir() {
         let tmpdir = tmpdir();
         let filename = &tmpdir.join("file_stat_correct_on_is_dir");
         mkdir(filename, io::UserRWX);
@@ -925,7 +892,7 @@ mod test {
         rmdir(filename);
     })
 
-    test!(fn file_test_fileinfo_false_when_checking_is_file_on_a_directory() {
+    iotest!(fn file_test_fileinfo_false_when_checking_is_file_on_a_directory() {
         let tmpdir = tmpdir();
         let dir = &tmpdir.join("fileinfo_false_on_dir");
         mkdir(dir, io::UserRWX);
@@ -933,7 +900,7 @@ mod test {
         rmdir(dir);
     })
 
-    test!(fn file_test_fileinfo_check_exists_before_and_after_file_creation() {
+    iotest!(fn file_test_fileinfo_check_exists_before_and_after_file_creation() {
         let tmpdir = tmpdir();
         let file = &tmpdir.join("fileinfo_check_exists_b_and_a.txt");
         File::create(file).write(bytes!("foo"));
@@ -942,7 +909,7 @@ mod test {
         assert!(!file.exists());
     })
 
-    test!(fn file_test_directoryinfo_check_exists_before_and_after_mkdir() {
+    iotest!(fn file_test_directoryinfo_check_exists_before_and_after_mkdir() {
         let tmpdir = tmpdir();
         let dir = &tmpdir.join("before_and_after_dir");
         assert!(!dir.exists());
@@ -953,7 +920,7 @@ mod test {
         assert!(!dir.exists());
     })
 
-    test!(fn file_test_directoryinfo_readdir() {
+    iotest!(fn file_test_directoryinfo_readdir() {
         use std::str;
         let tmpdir = tmpdir();
         let dir = &tmpdir.join("di_readdir");
@@ -984,11 +951,11 @@ mod test {
         rmdir(dir);
     })
 
-    test!(fn recursive_mkdir_slash() {
+    iotest!(fn recursive_mkdir_slash() {
         mkdir_recursive(&Path::new("/"), io::UserRWX);
     })
 
-    test!(fn unicode_path_is_dir() {
+    iotest!(fn unicode_path_is_dir() {
         assert!(Path::new(".").is_dir());
         assert!(!Path::new("test/stdtest/fs.rs").is_dir());
 
@@ -1006,7 +973,7 @@ mod test {
         assert!(filepath.exists());
     })
 
-    test!(fn unicode_path_exists() {
+    iotest!(fn unicode_path_exists() {
         assert!(Path::new(".").exists());
         assert!(!Path::new("test/nonexistent-bogus-path").exists());
 
@@ -1018,7 +985,7 @@ mod test {
         assert!(!Path::new("test/unicode-bogus-path-각丁ー再见").exists());
     })
 
-    test!(fn copy_file_does_not_exist() {
+    iotest!(fn copy_file_does_not_exist() {
         let from = Path::new("test/nonexistent-bogus-path");
         let to = Path::new("test/other-bogus-path");
         match io::result(|| copy(&from, &to)) {
@@ -1030,7 +997,7 @@ mod test {
         }
     })
 
-    test!(fn copy_file_ok() {
+    iotest!(fn copy_file_ok() {
         let tmpdir = tmpdir();
         let input = tmpdir.join("in.txt");
         let out = tmpdir.join("out.txt");
@@ -1043,7 +1010,7 @@ mod test {
         assert_eq!(input.stat().perm, out.stat().perm);
     })
 
-    test!(fn copy_file_dst_dir() {
+    iotest!(fn copy_file_dst_dir() {
         let tmpdir = tmpdir();
         let out = tmpdir.join("out");
 
@@ -1053,7 +1020,7 @@ mod test {
         }
     })
 
-    test!(fn copy_file_dst_exists() {
+    iotest!(fn copy_file_dst_exists() {
         let tmpdir = tmpdir();
         let input = tmpdir.join("in");
         let output = tmpdir.join("out");
@@ -1066,7 +1033,7 @@ mod test {
                    (bytes!("foo")).to_owned());
     })
 
-    test!(fn copy_file_src_dir() {
+    iotest!(fn copy_file_src_dir() {
         let tmpdir = tmpdir();
         let out = tmpdir.join("out");
 
@@ -1076,7 +1043,7 @@ mod test {
         assert!(!out.exists());
     })
 
-    test!(fn copy_file_preserves_perm_bits() {
+    iotest!(fn copy_file_preserves_perm_bits() {
         let tmpdir = tmpdir();
         let input = tmpdir.join("in.txt");
         let out = tmpdir.join("out.txt");
@@ -1091,7 +1058,7 @@ mod test {
     })
 
     #[cfg(not(windows))] // FIXME(#10264) operation not permitted?
-    test!(fn symlinks_work() {
+    iotest!(fn symlinks_work() {
         let tmpdir = tmpdir();
         let input = tmpdir.join("in.txt");
         let out = tmpdir.join("out.txt");
@@ -1106,14 +1073,14 @@ mod test {
     })
 
     #[cfg(not(windows))] // apparently windows doesn't like symlinks
-    test!(fn symlink_noexist() {
+    iotest!(fn symlink_noexist() {
         let tmpdir = tmpdir();
         // symlinks can point to things that don't exist
         symlink(&tmpdir.join("foo"), &tmpdir.join("bar"));
         assert!(readlink(&tmpdir.join("bar")).unwrap() == tmpdir.join("foo"));
     })
 
-    test!(fn readlink_not_symlink() {
+    iotest!(fn readlink_not_symlink() {
         let tmpdir = tmpdir();
         match io::result(|| readlink(&*tmpdir)) {
             Ok(..) => fail!("wanted a failure"),
@@ -1121,7 +1088,7 @@ mod test {
         }
     })
 
-    test!(fn links_work() {
+    iotest!(fn links_work() {
         let tmpdir = tmpdir();
         let input = tmpdir.join("in.txt");
         let out = tmpdir.join("out.txt");
@@ -1147,7 +1114,7 @@ mod test {
         }
     })
 
-    test!(fn chmod_works() {
+    iotest!(fn chmod_works() {
         let tmpdir = tmpdir();
         let file = tmpdir.join("in.txt");
 
@@ -1164,7 +1131,7 @@ mod test {
         chmod(&file, io::UserFile);
     })
 
-    test!(fn sync_doesnt_kill_anything() {
+    iotest!(fn sync_doesnt_kill_anything() {
         let tmpdir = tmpdir();
         let path = tmpdir.join("in.txt");
 
@@ -1177,7 +1144,7 @@ mod test {
         drop(file);
     })
 
-    test!(fn truncate_works() {
+    iotest!(fn truncate_works() {
         let tmpdir = tmpdir();
         let path = tmpdir.join("in.txt");
 
@@ -1208,7 +1175,7 @@ mod test {
         drop(file);
     })
 
-    test!(fn open_flavors() {
+    iotest!(fn open_flavors() {
         let tmpdir = tmpdir();
 
         match io::result(|| File::open_mode(&tmpdir.join("a"), io::Open,
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index bd0b9e08b7c..2d52986294d 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -164,9 +164,6 @@ requests are implemented by descheduling the running task and
 performing an asynchronous request; the task is only resumed once the
 asynchronous request completes.
 
-For blocking (but possibly more efficient) implementations, look
-in the `io::native` module.
-
 # Error Handling
 
 I/O is an area where nearly every operation can result in unexpected
@@ -316,6 +313,9 @@ pub use self::net::udp::UdpStream;
 pub use self::pipe::PipeStream;
 pub use self::process::Process;
 
+/// Various utility functions useful for writing I/O tests
+pub mod test;
+
 /// Synchronous, non-blocking filesystem operations.
 pub mod fs;
 
@@ -349,8 +349,6 @@ pub mod timer;
 /// Buffered I/O wrappers
 pub mod buffered;
 
-pub mod native;
-
 /// Signal handling
 pub mod signal;
 
diff --git a/src/libstd/io/net/addrinfo.rs b/src/libstd/io/net/addrinfo.rs
index 7df4fdd2266..6d968de209c 100644
--- a/src/libstd/io/net/addrinfo.rs
+++ b/src/libstd/io/net/addrinfo.rs
@@ -18,8 +18,6 @@ getaddrinfo()
 */
 
 use option::{Option, Some, None};
-use result::{Ok, Err};
-use io::{io_error};
 use io::net::ip::{SocketAddr, IpAddr};
 use rt::rtio::{IoFactory, LocalIo};
 use vec::ImmutableVector;
@@ -97,14 +95,7 @@ pub fn get_host_addresses(host: &str) -> Option<~[IpAddr]> {
 ///      consumption just yet.
 fn lookup(hostname: Option<&str>, servname: Option<&str>, hint: Option<Hint>)
           -> Option<~[Info]> {
-    let mut io = LocalIo::borrow();
-    match io.get().get_host_addresses(hostname, servname, hint) {
-        Ok(i) => Some(i),
-        Err(ioerr) => {
-            io_error::cond.raise(ioerr);
-            None
-        }
-    }
+    LocalIo::maybe_raise(|io| io.get_host_addresses(hostname, servname, hint))
 }
 
 #[cfg(test)]
diff --git a/src/libstd/io/net/tcp.rs b/src/libstd/io/net/tcp.rs
index a6230ede7e3..e7787692dd2 100644
--- a/src/libstd/io/net/tcp.rs
+++ b/src/libstd/io/net/tcp.rs
@@ -26,17 +26,9 @@ impl TcpStream {
     }
 
     pub fn connect(addr: SocketAddr) -> Option<TcpStream> {
-        let result = {
-            let mut io = LocalIo::borrow();
-            io.get().tcp_connect(addr)
-        };
-        match result {
-            Ok(s) => Some(TcpStream::new(s)),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| {
+            io.tcp_connect(addr).map(TcpStream::new)
+        })
     }
 
     pub fn peer_name(&mut self) -> Option<SocketAddr> {
@@ -94,14 +86,9 @@ pub struct TcpListener {
 
 impl TcpListener {
     pub fn bind(addr: SocketAddr) -> Option<TcpListener> {
-        let mut io = LocalIo::borrow();
-        match io.get().tcp_bind(addr) {
-            Ok(l) => Some(TcpListener { obj: l }),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| {
+            io.tcp_bind(addr).map(|l| TcpListener { obj: l })
+        })
     }
 
     pub fn socket_name(&mut self) -> Option<SocketAddr> {
@@ -147,513 +134,473 @@ impl Acceptor<TcpStream> for TcpAcceptor {
 #[cfg(test)]
 mod test {
     use super::*;
-    use rt::test::*;
     use io::net::ip::{Ipv4Addr, SocketAddr};
     use io::*;
+    use io::test::{next_test_ip4, next_test_ip6};
     use prelude::*;
 
     #[test] #[ignore]
     fn bind_error() {
-        do run_in_mt_newsched_task {
-            let mut called = false;
-            io_error::cond.trap(|e| {
-                assert!(e.kind == PermissionDenied);
-                called = true;
-            }).inside(|| {
-                let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
-                let listener = TcpListener::bind(addr);
-                assert!(listener.is_none());
-            });
-            assert!(called);
-        }
+        let mut called = false;
+        io_error::cond.trap(|e| {
+            assert!(e.kind == PermissionDenied);
+            called = true;
+        }).inside(|| {
+            let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
+            let listener = TcpListener::bind(addr);
+            assert!(listener.is_none());
+        });
+        assert!(called);
     }
 
     #[test]
     fn connect_error() {
-        do run_in_mt_newsched_task {
-            let mut called = false;
-            io_error::cond.trap(|e| {
-                let expected_error = if cfg!(unix) {
-                    ConnectionRefused
-                } else {
-                    // On Win32, opening port 1 gives WSAEADDRNOTAVAIL error.
-                    OtherIoError
-                };
-                assert_eq!(e.kind, expected_error);
-                called = true;
-            }).inside(|| {
-                let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
-                let stream = TcpStream::connect(addr);
-                assert!(stream.is_none());
-            });
-            assert!(called);
-        }
+        let mut called = false;
+        io_error::cond.trap(|e| {
+            let expected_error = if cfg!(unix) {
+                ConnectionRefused
+            } else {
+                // On Win32, opening port 1 gives WSAEADDRNOTAVAIL error.
+                OtherIoError
+            };
+            assert_eq!(e.kind, expected_error);
+            called = true;
+        }).inside(|| {
+            let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
+            let stream = TcpStream::connect(addr);
+            assert!(stream.is_none());
+        });
+        assert!(called);
     }
 
     #[test]
     fn smoke_test_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let mut buf = [0];
-                stream.read(buf);
-                assert!(buf[0] == 99);
-            }
+        let addr = next_test_ip4();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let mut stream = TcpStream::connect(addr);
             stream.write([99]);
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let mut buf = [0];
+        stream.read(buf);
+        assert!(buf[0] == 99);
     }
 
     #[test]
     fn smoke_test_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let mut buf = [0];
-                stream.read(buf);
-                assert!(buf[0] == 99);
-            }
+        let addr = next_test_ip6();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let mut stream = TcpStream::connect(addr);
             stream.write([99]);
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let mut buf = [0];
+        stream.read(buf);
+        assert!(buf[0] == 99);
     }
 
     #[test]
     fn read_eof_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let mut buf = [0];
-                let nread = stream.read(buf);
-                assert!(nread.is_none());
-            }
+        let addr = next_test_ip4();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let _stream = TcpStream::connect(addr);
             // Close
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let mut buf = [0];
+        let nread = stream.read(buf);
+        assert!(nread.is_none());
     }
 
     #[test]
     fn read_eof_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let mut buf = [0];
-                let nread = stream.read(buf);
-                assert!(nread.is_none());
-            }
+        let addr = next_test_ip6();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let _stream = TcpStream::connect(addr);
             // Close
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let mut buf = [0];
+        let nread = stream.read(buf);
+        assert!(nread.is_none());
     }
 
     #[test]
     fn read_eof_twice_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let mut buf = [0];
-                let nread = stream.read(buf);
-                assert!(nread.is_none());
-                io_error::cond.trap(|e| {
-                    if cfg!(windows) {
-                        assert_eq!(e.kind, NotConnected);
-                    } else {
-                        fail!();
-                    }
-                }).inside(|| {
-                    let nread = stream.read(buf);
-                    assert!(nread.is_none());
-                })
-            }
+        let addr = next_test_ip4();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let _stream = TcpStream::connect(addr);
             // Close
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let mut buf = [0];
+        let nread = stream.read(buf);
+        assert!(nread.is_none());
+        io_error::cond.trap(|e| {
+            if cfg!(windows) {
+                assert_eq!(e.kind, NotConnected);
+            } else {
+                fail!();
+            }
+        }).inside(|| {
+            let nread = stream.read(buf);
+            assert!(nread.is_none());
+        })
     }
 
     #[test]
     fn read_eof_twice_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let mut buf = [0];
-                let nread = stream.read(buf);
-                assert!(nread.is_none());
-                io_error::cond.trap(|e| {
-                    if cfg!(windows) {
-                        assert_eq!(e.kind, NotConnected);
-                    } else {
-                        fail!();
-                    }
-                }).inside(|| {
-                    let nread = stream.read(buf);
-                    assert!(nread.is_none());
-                })
-            }
+        let addr = next_test_ip6();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let _stream = TcpStream::connect(addr);
             // Close
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let mut buf = [0];
+        let nread = stream.read(buf);
+        assert!(nread.is_none());
+        io_error::cond.trap(|e| {
+            if cfg!(windows) {
+                assert_eq!(e.kind, NotConnected);
+            } else {
+                fail!();
+            }
+        }).inside(|| {
+            let nread = stream.read(buf);
+            assert!(nread.is_none());
+        })
     }
 
     #[test]
     fn write_close_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let buf = [0];
-                loop {
-                    let mut stop = false;
-                    io_error::cond.trap(|e| {
-                        // NB: ECONNRESET on linux, EPIPE on mac, ECONNABORTED
-                        //     on windows
-                        assert!(e.kind == ConnectionReset ||
-                                e.kind == BrokenPipe ||
-                                e.kind == ConnectionAborted,
-                                "unknown error: {:?}", e);
-                        stop = true;
-                    }).inside(|| {
-                        stream.write(buf);
-                    });
-                    if stop { break }
-                }
-            }
+        let addr = next_test_ip4();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let _stream = TcpStream::connect(addr);
             // Close
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let buf = [0];
+        loop {
+            let mut stop = false;
+            io_error::cond.trap(|e| {
+                // NB: ECONNRESET on linux, EPIPE on mac, ECONNABORTED
+                //     on windows
+                assert!(e.kind == ConnectionReset ||
+                        e.kind == BrokenPipe ||
+                        e.kind == ConnectionAborted,
+                        "unknown error: {:?}", e);
+                stop = true;
+            }).inside(|| {
+                stream.write(buf);
+            });
+            if stop { break }
+        }
     }
 
     #[test]
     fn write_close_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                let mut stream = acceptor.accept();
-                let buf = [0];
-                loop {
-                    let mut stop = false;
-                    io_error::cond.trap(|e| {
-                        // NB: ECONNRESET on linux, EPIPE on mac, ECONNABORTED
-                        //     on windows
-                        assert!(e.kind == ConnectionReset ||
-                                e.kind == BrokenPipe ||
-                                e.kind == ConnectionAborted,
-                                "unknown error: {:?}", e);
-                        stop = true;
-                    }).inside(|| {
-                        stream.write(buf);
-                    });
-                    if stop { break }
-                }
-            }
+        let addr = next_test_ip6();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             let _stream = TcpStream::connect(addr);
             // Close
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        let mut stream = acceptor.accept();
+        let buf = [0];
+        loop {
+            let mut stop = false;
+            io_error::cond.trap(|e| {
+                // NB: ECONNRESET on linux, EPIPE on mac, ECONNABORTED
+                //     on windows
+                assert!(e.kind == ConnectionReset ||
+                        e.kind == BrokenPipe ||
+                        e.kind == ConnectionAborted,
+                        "unknown error: {:?}", e);
+                stop = true;
+            }).inside(|| {
+                stream.write(buf);
+            });
+            if stop { break }
+        }
     }
 
     #[test]
     fn multiple_connect_serial_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            let max = 10;
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                for ref mut stream in acceptor.incoming().take(max) {
-                    let mut buf = [0];
-                    stream.read(buf);
-                    assert_eq!(buf[0], 99);
-                }
-            }
+        let addr = next_test_ip4();
+        let max = 10;
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             max.times(|| {
                 let mut stream = TcpStream::connect(addr);
                 stream.write([99]);
             });
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        for ref mut stream in acceptor.incoming().take(max) {
+            let mut buf = [0];
+            stream.read(buf);
+            assert_eq!(buf[0], 99);
+        }
     }
 
     #[test]
     fn multiple_connect_serial_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            let max = 10;
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                for ref mut stream in acceptor.incoming().take(max) {
-                    let mut buf = [0];
-                    stream.read(buf);
-                    assert_eq!(buf[0], 99);
-                }
-            }
+        let addr = next_test_ip6();
+        let max = 10;
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             max.times(|| {
                 let mut stream = TcpStream::connect(addr);
                 stream.write([99]);
             });
         }
+
+        let mut acceptor = TcpListener::bind(addr).listen();
+        chan.send(());
+        for ref mut stream in acceptor.incoming().take(max) {
+            let mut buf = [0];
+            stream.read(buf);
+            assert_eq!(buf[0], 99);
+        }
     }
 
     #[test]
     fn multiple_connect_interleaved_greedy_schedule_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            static MAX: int = 10;
-            let (port, chan) = Chan::new();
+        let addr = next_test_ip4();
+        static MAX: int = 10;
+        let (port, chan) = Chan::new();
 
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                for (i, stream) in acceptor.incoming().enumerate().take(MAX as uint) {
-                    // Start another task to handle the connection
-                    do spawntask {
-                        let mut stream = stream;
-                        let mut buf = [0];
-                        stream.read(buf);
-                        assert!(buf[0] == i as u8);
-                        debug!("read");
-                    }
+        do spawn {
+            let mut acceptor = TcpListener::bind(addr).listen();
+            chan.send(());
+            for (i, stream) in acceptor.incoming().enumerate().take(MAX as uint) {
+                // Start another task to handle the connection
+                do spawn {
+                    let mut stream = stream;
+                    let mut buf = [0];
+                    stream.read(buf);
+                    assert!(buf[0] == i as u8);
+                    debug!("read");
                 }
             }
+        }
 
-            port.recv();
-            connect(0, addr);
+        port.recv();
+        connect(0, addr);
 
-            fn connect(i: int, addr: SocketAddr) {
-                if i == MAX { return }
+        fn connect(i: int, addr: SocketAddr) {
+            if i == MAX { return }
 
-                do spawntask {
-                    debug!("connecting");
-                    let mut stream = TcpStream::connect(addr);
-                    // Connect again before writing
-                    connect(i + 1, addr);
-                    debug!("writing");
-                    stream.write([i as u8]);
-                }
+            do spawn {
+                debug!("connecting");
+                let mut stream = TcpStream::connect(addr);
+                // Connect again before writing
+                connect(i + 1, addr);
+                debug!("writing");
+                stream.write([i as u8]);
             }
         }
     }
 
     #[test]
     fn multiple_connect_interleaved_greedy_schedule_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            static MAX: int = 10;
-            let (port, chan) = Chan::new();
+        let addr = next_test_ip6();
+        static MAX: int = 10;
+        let (port, chan) = Chan::<()>::new();
 
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                for (i, stream) in acceptor.incoming().enumerate().take(MAX as uint) {
-                    // Start another task to handle the connection
-                    do spawntask {
-                        let mut stream = stream;
-                        let mut buf = [0];
-                        stream.read(buf);
-                        assert!(buf[0] == i as u8);
-                        debug!("read");
-                    }
+        do spawn {
+            let mut acceptor = TcpListener::bind(addr).listen();
+            chan.send(());
+            for (i, stream) in acceptor.incoming().enumerate().take(MAX as uint) {
+                // Start another task to handle the connection
+                do spawn {
+                    let mut stream = stream;
+                    let mut buf = [0];
+                    stream.read(buf);
+                    assert!(buf[0] == i as u8);
+                    debug!("read");
                 }
             }
+        }
 
-            port.recv();
-            connect(0, addr);
+        port.recv();
+        connect(0, addr);
 
-            fn connect(i: int, addr: SocketAddr) {
-                if i == MAX { return }
+        fn connect(i: int, addr: SocketAddr) {
+            if i == MAX { return }
 
-                do spawntask {
-                    debug!("connecting");
-                    let mut stream = TcpStream::connect(addr);
-                    // Connect again before writing
-                    connect(i + 1, addr);
-                    debug!("writing");
-                    stream.write([i as u8]);
-                }
+            do spawn {
+                debug!("connecting");
+                let mut stream = TcpStream::connect(addr);
+                // Connect again before writing
+                connect(i + 1, addr);
+                debug!("writing");
+                stream.write([i as u8]);
             }
         }
     }
 
     #[test]
     fn multiple_connect_interleaved_lazy_schedule_ip4() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip4();
-            static MAX: int = 10;
-            let (port, chan) = Chan::new();
+        let addr = next_test_ip4();
+        static MAX: int = 10;
+        let (port, chan) = Chan::new();
 
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                for stream in acceptor.incoming().take(MAX as uint) {
-                    // Start another task to handle the connection
-                    do spawntask_later {
-                        let mut stream = stream;
-                        let mut buf = [0];
-                        stream.read(buf);
-                        assert!(buf[0] == 99);
-                        debug!("read");
-                    }
+        do spawn {
+            let mut acceptor = TcpListener::bind(addr).listen();
+            chan.send(());
+            for stream in acceptor.incoming().take(MAX as uint) {
+                // Start another task to handle the connection
+                do spawn {
+                    let mut stream = stream;
+                    let mut buf = [0];
+                    stream.read(buf);
+                    assert!(buf[0] == 99);
+                    debug!("read");
                 }
             }
+        }
 
-            port.recv();
-            connect(0, addr);
+        port.recv();
+        connect(0, addr);
 
-            fn connect(i: int, addr: SocketAddr) {
-                if i == MAX { return }
+        fn connect(i: int, addr: SocketAddr) {
+            if i == MAX { return }
 
-                do spawntask_later {
-                    debug!("connecting");
-                    let mut stream = TcpStream::connect(addr);
-                    // Connect again before writing
-                    connect(i + 1, addr);
-                    debug!("writing");
-                    stream.write([99]);
-                }
+            do spawn {
+                debug!("connecting");
+                let mut stream = TcpStream::connect(addr);
+                // Connect again before writing
+                connect(i + 1, addr);
+                debug!("writing");
+                stream.write([99]);
             }
         }
     }
     #[test]
     fn multiple_connect_interleaved_lazy_schedule_ip6() {
-        do run_in_mt_newsched_task {
-            let addr = next_test_ip6();
-            static MAX: int = 10;
-            let (port, chan) = Chan::new();
+        let addr = next_test_ip6();
+        static MAX: int = 10;
+        let (port, chan) = Chan::new();
 
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-                for stream in acceptor.incoming().take(MAX as uint) {
-                    // Start another task to handle the connection
-                    do spawntask_later {
-                        let mut stream = stream;
-                        let mut buf = [0];
-                        stream.read(buf);
-                        assert!(buf[0] == 99);
-                        debug!("read");
-                    }
+        do spawn {
+            let mut acceptor = TcpListener::bind(addr).listen();
+            chan.send(());
+            for stream in acceptor.incoming().take(MAX as uint) {
+                // Start another task to handle the connection
+                do spawn {
+                    let mut stream = stream;
+                    let mut buf = [0];
+                    stream.read(buf);
+                    assert!(buf[0] == 99);
+                    debug!("read");
                 }
             }
+        }
 
-            port.recv();
-            connect(0, addr);
+        port.recv();
+        connect(0, addr);
 
-            fn connect(i: int, addr: SocketAddr) {
-                if i == MAX { return }
+        fn connect(i: int, addr: SocketAddr) {
+            if i == MAX { return }
 
-                do spawntask_later {
-                    debug!("connecting");
-                    let mut stream = TcpStream::connect(addr);
-                    // Connect again before writing
-                    connect(i + 1, addr);
-                    debug!("writing");
-                    stream.write([99]);
-                }
+            do spawn {
+                debug!("connecting");
+                let mut stream = TcpStream::connect(addr);
+                // Connect again before writing
+                connect(i + 1, addr);
+                debug!("writing");
+                stream.write([99]);
             }
         }
     }
 
     #[cfg(test)]
     fn socket_name(addr: SocketAddr) {
-        do run_in_mt_newsched_task {
-            do spawntask {
-                let mut listener = TcpListener::bind(addr).unwrap();
+        let mut listener = TcpListener::bind(addr).unwrap();
 
-                // Make sure socket_name gives
-                // us the socket we binded to.
-                let so_name = listener.socket_name();
-                assert!(so_name.is_some());
-                assert_eq!(addr, so_name.unwrap());
-
-            }
-        }
+        // Make sure socket_name gives
+        // us the socket we binded to.
+        let so_name = listener.socket_name();
+        assert!(so_name.is_some());
+        assert_eq!(addr, so_name.unwrap());
     }
 
     #[cfg(test)]
     fn peer_name(addr: SocketAddr) {
-        do run_in_mt_newsched_task {
-            let (port, chan) = Chan::new();
+        let (port, chan) = Chan::new();
 
-            do spawntask {
-                let mut acceptor = TcpListener::bind(addr).listen();
-                chan.send(());
-
-                acceptor.accept();
-            }
-
-            port.recv();
-            let stream = TcpStream::connect(addr);
-
-            assert!(stream.is_some());
-            let mut stream = stream.unwrap();
-
-            // Make sure peer_name gives us the
-            // address/port of the peer we've
-            // connected to.
-            let peer_name = stream.peer_name();
-            assert!(peer_name.is_some());
-            assert_eq!(addr, peer_name.unwrap());
+        do spawn {
+            let mut acceptor = TcpListener::bind(addr).listen();
+            chan.send(());
+            acceptor.accept();
         }
+
+        port.recv();
+        let stream = TcpStream::connect(addr);
+
+        assert!(stream.is_some());
+        let mut stream = stream.unwrap();
+
+        // Make sure peer_name gives us the
+        // address/port of the peer we've
+        // connected to.
+        let peer_name = stream.peer_name();
+        assert!(peer_name.is_some());
+        assert_eq!(addr, peer_name.unwrap());
     }
 
     #[test]
@@ -668,5 +615,4 @@ mod test {
         //peer_name(next_test_ip6());
         socket_name(next_test_ip6());
     }
-
 }
diff --git a/src/libstd/io/net/udp.rs b/src/libstd/io/net/udp.rs
index 1e56f964bea..7cb8f741cf3 100644
--- a/src/libstd/io/net/udp.rs
+++ b/src/libstd/io/net/udp.rs
@@ -21,14 +21,9 @@ pub struct UdpSocket {
 
 impl UdpSocket {
     pub fn bind(addr: SocketAddr) -> Option<UdpSocket> {
-        let mut io = LocalIo::borrow();
-        match io.get().udp_bind(addr) {
-            Ok(s) => Some(UdpSocket { obj: s }),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| {
+            io.udp_bind(addr).map(|s| UdpSocket { obj: s })
+        })
     }
 
     pub fn recvfrom(&mut self, buf: &mut [u8]) -> Option<(uint, SocketAddr)> {
@@ -104,52 +99,32 @@ impl Writer for UdpStream {
 #[cfg(test)]
 mod test {
     use super::*;
-    use rt::test::*;
     use io::net::ip::{Ipv4Addr, SocketAddr};
     use io::*;
+    use io::test::*;
     use prelude::*;
 
     #[test]  #[ignore]
     fn bind_error() {
-        do run_in_mt_newsched_task {
-            let mut called = false;
-            io_error::cond.trap(|e| {
-                assert!(e.kind == PermissionDenied);
-                called = true;
-            }).inside(|| {
-                let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
-                let socket = UdpSocket::bind(addr);
-                assert!(socket.is_none());
-            });
-            assert!(called);
-        }
+        let mut called = false;
+        io_error::cond.trap(|e| {
+            assert!(e.kind == PermissionDenied);
+            called = true;
+        }).inside(|| {
+            let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
+            let socket = UdpSocket::bind(addr);
+            assert!(socket.is_none());
+        });
+        assert!(called);
     }
 
     #[test]
     fn socket_smoke_test_ip4() {
-        do run_in_mt_newsched_task {
-            let server_ip = next_test_ip4();
-            let client_ip = next_test_ip4();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                match UdpSocket::bind(server_ip) {
-                    Some(ref mut server) => {
-                        chan.send(());
-                        let mut buf = [0];
-                        match server.recvfrom(buf) {
-                            Some((nread, src)) => {
-                                assert_eq!(nread, 1);
-                                assert_eq!(buf[0], 99);
-                                assert_eq!(src, client_ip);
-                            }
-                            None => fail!()
-                        }
-                    }
-                    None => fail!()
-                }
-            }
+        let server_ip = next_test_ip4();
+        let client_ip = next_test_ip4();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             match UdpSocket::bind(client_ip) {
                 Some(ref mut client) => {
                     port.recv();
@@ -158,33 +133,31 @@ mod test {
                 None => fail!()
             }
         }
+
+        match UdpSocket::bind(server_ip) {
+            Some(ref mut server) => {
+                chan.send(());
+                let mut buf = [0];
+                match server.recvfrom(buf) {
+                    Some((nread, src)) => {
+                        assert_eq!(nread, 1);
+                        assert_eq!(buf[0], 99);
+                        assert_eq!(src, client_ip);
+                    }
+                    None => fail!()
+                }
+            }
+            None => fail!()
+        }
     }
 
     #[test]
     fn socket_smoke_test_ip6() {
-        do run_in_mt_newsched_task {
-            let server_ip = next_test_ip6();
-            let client_ip = next_test_ip6();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                match UdpSocket::bind(server_ip) {
-                    Some(ref mut server) => {
-                        chan.send(());
-                        let mut buf = [0];
-                        match server.recvfrom(buf) {
-                            Some((nread, src)) => {
-                                assert_eq!(nread, 1);
-                                assert_eq!(buf[0], 99);
-                                assert_eq!(src, client_ip);
-                            }
-                            None => fail!()
-                        }
-                    }
-                    None => fail!()
-                }
-            }
+        let server_ip = next_test_ip6();
+        let client_ip = next_test_ip6();
+        let (port, chan) = Chan::<()>::new();
 
+        do spawn {
             match UdpSocket::bind(client_ip) {
                 Some(ref mut client) => {
                     port.recv();
@@ -193,34 +166,31 @@ mod test {
                 None => fail!()
             }
         }
-    }
 
-    #[test]
-    fn stream_smoke_test_ip4() {
-        do run_in_mt_newsched_task {
-            let server_ip = next_test_ip4();
-            let client_ip = next_test_ip4();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                match UdpSocket::bind(server_ip) {
-                    Some(server) => {
-                        let server = ~server;
-                        let mut stream = server.connect(client_ip);
-                        chan.send(());
-                        let mut buf = [0];
-                        match stream.read(buf) {
-                            Some(nread) => {
-                                assert_eq!(nread, 1);
-                                assert_eq!(buf[0], 99);
-                            }
-                            None => fail!()
-                        }
+        match UdpSocket::bind(server_ip) {
+            Some(ref mut server) => {
+                chan.send(());
+                let mut buf = [0];
+                match server.recvfrom(buf) {
+                    Some((nread, src)) => {
+                        assert_eq!(nread, 1);
+                        assert_eq!(buf[0], 99);
+                        assert_eq!(src, client_ip);
                     }
                     None => fail!()
                 }
             }
+            None => fail!()
+        }
+    }
 
+    #[test]
+    fn stream_smoke_test_ip4() {
+        let server_ip = next_test_ip4();
+        let client_ip = next_test_ip4();
+        let (port, chan) = Chan::new();
+
+        do spawn {
             match UdpSocket::bind(client_ip) {
                 Some(client) => {
                     let client = ~client;
@@ -231,34 +201,32 @@ mod test {
                 None => fail!()
             }
         }
+
+        match UdpSocket::bind(server_ip) {
+            Some(server) => {
+                let server = ~server;
+                let mut stream = server.connect(client_ip);
+                chan.send(());
+                let mut buf = [0];
+                match stream.read(buf) {
+                    Some(nread) => {
+                        assert_eq!(nread, 1);
+                        assert_eq!(buf[0], 99);
+                    }
+                    None => fail!()
+                }
+            }
+            None => fail!()
+        }
     }
 
     #[test]
     fn stream_smoke_test_ip6() {
-        do run_in_mt_newsched_task {
-            let server_ip = next_test_ip6();
-            let client_ip = next_test_ip6();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                match UdpSocket::bind(server_ip) {
-                    Some(server) => {
-                        let server = ~server;
-                        let mut stream = server.connect(client_ip);
-                        chan.send(());
-                        let mut buf = [0];
-                        match stream.read(buf) {
-                            Some(nread) => {
-                                assert_eq!(nread, 1);
-                                assert_eq!(buf[0], 99);
-                            }
-                            None => fail!()
-                        }
-                    }
-                    None => fail!()
-                }
-            }
+        let server_ip = next_test_ip6();
+        let client_ip = next_test_ip6();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             match UdpSocket::bind(client_ip) {
                 Some(client) => {
                     let client = ~client;
@@ -269,25 +237,36 @@ mod test {
                 None => fail!()
             }
         }
+
+        match UdpSocket::bind(server_ip) {
+            Some(server) => {
+                let server = ~server;
+                let mut stream = server.connect(client_ip);
+                chan.send(());
+                let mut buf = [0];
+                match stream.read(buf) {
+                    Some(nread) => {
+                        assert_eq!(nread, 1);
+                        assert_eq!(buf[0], 99);
+                    }
+                    None => fail!()
+                }
+            }
+            None => fail!()
+        }
     }
 
-    #[cfg(test)]
     fn socket_name(addr: SocketAddr) {
-        do run_in_mt_newsched_task {
-            do spawntask {
-                let server = UdpSocket::bind(addr);
+        let server = UdpSocket::bind(addr);
 
-                assert!(server.is_some());
-                let mut server = server.unwrap();
+        assert!(server.is_some());
+        let mut server = server.unwrap();
 
-                // Make sure socket_name gives
-                // us the socket we binded to.
-                let so_name = server.socket_name();
-                assert!(so_name.is_some());
-                assert_eq!(addr, so_name.unwrap());
-
-            }
-        }
+        // Make sure socket_name gives
+        // us the socket we binded to.
+        let so_name = server.socket_name();
+        assert!(so_name.is_some());
+        assert_eq!(addr, so_name.unwrap());
     }
 
     #[test]
diff --git a/src/libstd/io/net/unix.rs b/src/libstd/io/net/unix.rs
index 2766aa9ad27..01b409d4316 100644
--- a/src/libstd/io/net/unix.rs
+++ b/src/libstd/io/net/unix.rs
@@ -59,14 +59,9 @@ impl UnixStream {
     ///     stream.write([1, 2, 3]);
     ///
     pub fn connect<P: ToCStr>(path: &P) -> Option<UnixStream> {
-        let mut io = LocalIo::borrow();
-        match io.get().unix_connect(&path.to_c_str()) {
-            Ok(s) => Some(UnixStream::new(s)),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| {
+            io.unix_connect(&path.to_c_str()).map(UnixStream::new)
+        })
     }
 }
 
@@ -107,14 +102,9 @@ impl UnixListener {
     ///     }
     ///
     pub fn bind<P: ToCStr>(path: &P) -> Option<UnixListener> {
-        let mut io = LocalIo::borrow();
-        match io.get().unix_bind(&path.to_c_str()) {
-            Ok(s) => Some(UnixListener{ obj: s }),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| {
+            io.unix_bind(&path.to_c_str()).map(|s| UnixListener { obj: s })
+        })
     }
 }
 
@@ -150,55 +140,49 @@ impl Acceptor<UnixStream> for UnixAcceptor {
 mod tests {
     use prelude::*;
     use super::*;
-    use rt::test::*;
     use io::*;
+    use io::test::*;
 
     fn smalltest(server: proc(UnixStream), client: proc(UnixStream)) {
-        do run_in_mt_newsched_task {
-            let path1 = next_test_unix();
-            let path2 = path1.clone();
-            let (client, server) = (client, server);
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = UnixListener::bind(&path1).listen();
-                chan.send(());
-                server(acceptor.accept().unwrap());
-            }
+        let path1 = next_test_unix();
+        let path2 = path1.clone();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             client(UnixStream::connect(&path2).unwrap());
         }
+
+        let mut acceptor = UnixListener::bind(&path1).listen();
+        chan.send(());
+        server(acceptor.accept().unwrap());
     }
 
     #[test]
     fn bind_error() {
-        do run_in_mt_newsched_task {
-            let mut called = false;
-            io_error::cond.trap(|e| {
-                assert!(e.kind == PermissionDenied);
-                called = true;
-            }).inside(|| {
-                let listener = UnixListener::bind(&("path/to/nowhere"));
-                assert!(listener.is_none());
-            });
-            assert!(called);
-        }
+        let mut called = false;
+        io_error::cond.trap(|e| {
+            assert!(e.kind == PermissionDenied);
+            called = true;
+        }).inside(|| {
+            let listener = UnixListener::bind(&("path/to/nowhere"));
+            assert!(listener.is_none());
+        });
+        assert!(called);
     }
 
     #[test]
     fn connect_error() {
-        do run_in_mt_newsched_task {
-            let mut called = false;
-            io_error::cond.trap(|e| {
-                assert_eq!(e.kind, FileNotFound);
-                called = true;
-            }).inside(|| {
-                let stream = UnixStream::connect(&("path/to/nowhere"));
-                assert!(stream.is_none());
-            });
-            assert!(called);
-        }
+        let mut called = false;
+        io_error::cond.trap(|e| {
+            assert_eq!(e.kind,
+                       if cfg!(windows) {OtherIoError} else {FileNotFound});
+            called = true;
+        }).inside(|| {
+            let stream = UnixStream::connect(&("path/to/nowhere"));
+            assert!(stream.is_none());
+        });
+        assert!(called);
     }
 
     #[test]
@@ -244,37 +228,33 @@ mod tests {
 
     #[test]
     fn accept_lots() {
-        do run_in_mt_newsched_task {
-            let times = 10;
-            let path1 = next_test_unix();
-            let path2 = path1.clone();
-            let (port, chan) = Chan::new();
-
-            do spawntask {
-                let mut acceptor = UnixListener::bind(&path1).listen();
-                chan.send(());
-                times.times(|| {
-                    let mut client = acceptor.accept();
-                    let mut buf = [0];
-                    client.read(buf);
-                    assert_eq!(buf[0], 100);
-                })
-            }
+        let times = 10;
+        let path1 = next_test_unix();
+        let path2 = path1.clone();
+        let (port, chan) = Chan::new();
 
+        do spawn {
             port.recv();
             times.times(|| {
                 let mut stream = UnixStream::connect(&path2);
                 stream.write([100]);
             })
         }
+
+        let mut acceptor = UnixListener::bind(&path1).listen();
+        chan.send(());
+        times.times(|| {
+            let mut client = acceptor.accept();
+            let mut buf = [0];
+            client.read(buf);
+            assert_eq!(buf[0], 100);
+        })
     }
 
     #[test]
     fn path_exists() {
-        do run_in_mt_newsched_task {
-            let path = next_test_unix();
-            let _acceptor = UnixListener::bind(&path).listen();
-            assert!(path.exists());
-        }
+        let path = next_test_unix();
+        let _acceptor = UnixListener::bind(&path).listen();
+        assert!(path.exists());
     }
 }
diff --git a/src/libstd/io/option.rs b/src/libstd/io/option.rs
index 61c5411f360..a661d6ab7eb 100644
--- a/src/libstd/io/option.rs
+++ b/src/libstd/io/option.rs
@@ -106,53 +106,46 @@ impl<T, A: Acceptor<T>> Acceptor<T> for Option<A> {
 mod test {
     use option::*;
     use super::super::mem::*;
-    use rt::test::*;
     use super::super::{PreviousIoError, io_error};
 
     #[test]
     fn test_option_writer() {
-        do run_in_mt_newsched_task {
-            let mut writer: Option<MemWriter> = Some(MemWriter::new());
-            writer.write([0, 1, 2]);
-            writer.flush();
-            assert_eq!(writer.unwrap().inner(), ~[0, 1, 2]);
-        }
+        let mut writer: Option<MemWriter> = Some(MemWriter::new());
+        writer.write([0, 1, 2]);
+        writer.flush();
+        assert_eq!(writer.unwrap().inner(), ~[0, 1, 2]);
     }
 
     #[test]
     fn test_option_writer_error() {
-        do run_in_mt_newsched_task {
-            let mut writer: Option<MemWriter> = None;
+        let mut writer: Option<MemWriter> = None;
 
-            let mut called = false;
-            io_error::cond.trap(|err| {
-                assert_eq!(err.kind, PreviousIoError);
-                called = true;
-            }).inside(|| {
-                writer.write([0, 0, 0]);
-            });
-            assert!(called);
+        let mut called = false;
+        io_error::cond.trap(|err| {
+            assert_eq!(err.kind, PreviousIoError);
+            called = true;
+        }).inside(|| {
+            writer.write([0, 0, 0]);
+        });
+        assert!(called);
 
-            let mut called = false;
-            io_error::cond.trap(|err| {
-                assert_eq!(err.kind, PreviousIoError);
-                called = true;
-            }).inside(|| {
-                writer.flush();
-            });
-            assert!(called);
-        }
+        let mut called = false;
+        io_error::cond.trap(|err| {
+            assert_eq!(err.kind, PreviousIoError);
+            called = true;
+        }).inside(|| {
+            writer.flush();
+        });
+        assert!(called);
     }
 
     #[test]
     fn test_option_reader() {
-        do run_in_mt_newsched_task {
-            let mut reader: Option<MemReader> = Some(MemReader::new(~[0, 1, 2, 3]));
-            let mut buf = [0, 0];
-            reader.read(buf);
-            assert_eq!(buf, [0, 1]);
-            assert!(!reader.eof());
-        }
+        let mut reader: Option<MemReader> = Some(MemReader::new(~[0, 1, 2, 3]));
+        let mut buf = [0, 0];
+        reader.read(buf);
+        assert_eq!(buf, [0, 1]);
+        assert!(!reader.eof());
     }
 
     #[test]
diff --git a/src/libstd/io/pipe.rs b/src/libstd/io/pipe.rs
index 252575ee445..2349c64a84b 100644
--- a/src/libstd/io/pipe.rs
+++ b/src/libstd/io/pipe.rs
@@ -14,10 +14,9 @@
 //! enough so that pipes can be created to child processes.
 
 use prelude::*;
-use super::{Reader, Writer};
 use io::{io_error, EndOfFile};
-use io::native::file;
-use rt::rtio::{LocalIo, RtioPipe};
+use libc;
+use rt::rtio::{RtioPipe, LocalIo};
 
 pub struct PipeStream {
     priv obj: ~RtioPipe,
@@ -43,15 +42,10 @@ impl PipeStream {
     ///
     /// If the pipe cannot be created, an error will be raised on the
     /// `io_error` condition.
-    pub fn open(fd: file::fd_t) -> Option<PipeStream> {
-        let mut io = LocalIo::borrow();
-        match io.get().pipe_open(fd) {
-            Ok(obj) => Some(PipeStream { obj: obj }),
-            Err(e) => {
-                io_error::cond.raise(e);
-                None
-            }
-        }
+    pub fn open(fd: libc::c_int) -> Option<PipeStream> {
+        LocalIo::maybe_raise(|io| {
+            io.pipe_open(fd).map(|obj| PipeStream { obj: obj })
+        })
     }
 
     pub fn new(inner: ~RtioPipe) -> PipeStream {
diff --git a/src/libstd/io/process.rs b/src/libstd/io/process.rs
index 001faa1ecaf..bbb2a7ef398 100644
--- a/src/libstd/io/process.rs
+++ b/src/libstd/io/process.rs
@@ -119,19 +119,17 @@ impl Process {
     /// Creates a new pipe initialized, but not bound to any particular
     /// source/destination
     pub fn new(config: ProcessConfig) -> Option<Process> {
-        let mut io = LocalIo::borrow();
-        match io.get().spawn(config) {
-            Ok((p, io)) => Some(Process{
-                handle: p,
-                io: io.move_iter().map(|p|
-                    p.map(|p| io::PipeStream::new(p))
-                ).collect()
-            }),
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        let mut config = Some(config);
+        LocalIo::maybe_raise(|io| {
+            io.spawn(config.take_unwrap()).map(|(p, io)| {
+                Process {
+                    handle: p,
+                    io: io.move_iter().map(|p| {
+                        p.map(|p| io::PipeStream::new(p))
+                    }).collect()
+                }
+            })
+        })
     }
 
     /// Returns the process id of this child process
diff --git a/src/libstd/io/signal.rs b/src/libstd/io/signal.rs
index 00d84e22c25..4cde35796a6 100644
--- a/src/libstd/io/signal.rs
+++ b/src/libstd/io/signal.rs
@@ -23,8 +23,7 @@ use clone::Clone;
 use comm::{Port, SharedChan};
 use container::{Map, MutableMap};
 use hashmap;
-use io::io_error;
-use result::{Err, Ok};
+use option::{Some, None};
 use rt::rtio::{IoFactory, LocalIo, RtioSignal};
 
 #[repr(int)]
@@ -122,16 +121,14 @@ impl Listener {
         if self.handles.contains_key(&signum) {
             return true; // self is already listening to signum, so succeed
         }
-        let mut io = LocalIo::borrow();
-        match io.get().signal(signum, self.chan.clone()) {
-            Ok(w) => {
-                self.handles.insert(signum, w);
+        match LocalIo::maybe_raise(|io| {
+            io.signal(signum, self.chan.clone())
+        }) {
+            Some(handle) => {
+                self.handles.insert(signum, handle);
                 true
-            },
-            Err(ioerr) => {
-                io_error::cond.raise(ioerr);
-                false
             }
+            None => false
         }
     }
 
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 41337075aa9..1e4fa7968dc 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -27,13 +27,13 @@ out.write(bytes!("Hello, world!"));
 */
 
 use fmt;
+use io::buffered::LineBufferedWriter;
+use io::{Reader, Writer, io_error, IoError, OtherIoError,
+         standard_error, EndOfFile};
 use libc;
 use option::{Option, Some, None};
 use result::{Ok, Err};
-use io::buffered::LineBufferedWriter;
 use rt::rtio::{DontClose, IoFactory, LocalIo, RtioFileStream, RtioTTY};
-use super::{Reader, Writer, io_error, IoError, OtherIoError,
-            standard_error, EndOfFile};
 
 // And so begins the tale of acquiring a uv handle to a stdio stream on all
 // platforms in all situations. Our story begins by splitting the world into two
@@ -69,19 +69,12 @@ enum StdSource {
 }
 
 fn src<T>(fd: libc::c_int, readable: bool, f: |StdSource| -> T) -> T {
-    let mut io = LocalIo::borrow();
-    match io.get().tty_open(fd, readable) {
-        Ok(tty) => f(TTY(tty)),
-        Err(_) => {
-            // It's not really that desirable if these handles are closed
-            // synchronously, and because they're squirreled away in a task
-            // structure the destructors will be run when the task is
-            // attempted to get destroyed. This means that if we run a
-            // synchronous destructor we'll attempt to do some scheduling
-            // operations which will just result in sadness.
-            f(File(io.get().fs_from_raw_fd(fd, DontClose)))
-        }
-    }
+    LocalIo::maybe_raise(|io| {
+        Ok(match io.tty_open(fd, readable) {
+            Ok(tty) => f(TTY(tty)),
+            Err(_) => f(File(io.fs_from_raw_fd(fd, DontClose))),
+        })
+    }).unwrap()
 }
 
 /// Creates a new non-blocking handle to the stdin of the current process.
@@ -138,7 +131,17 @@ fn with_task_stdout(f: |&mut Writer|) {
             }
 
             None => {
-                let mut io = stdout();
+                struct Stdout;
+                impl Writer for Stdout {
+                    fn write(&mut self, data: &[u8]) {
+                        unsafe {
+                            libc::write(libc::STDOUT_FILENO,
+                                        data.as_ptr() as *libc::c_void,
+                                        data.len() as libc::size_t);
+                        }
+                    }
+                }
+                let mut io = Stdout;
                 f(&mut io as &mut Writer);
             }
         }
@@ -304,23 +307,10 @@ impl Writer for StdWriter {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use rt::test::run_in_newsched_task;
-
-    #[test]
-    fn smoke_uv() {
+    iotest!(fn smoke() {
         // Just make sure we can acquire handles
         stdin();
         stdout();
         stderr();
-    }
-
-    #[test]
-    fn smoke_native() {
-        do run_in_newsched_task {
-            stdin();
-            stdout();
-            stderr();
-        }
-    }
+    })
 }
diff --git a/src/libstd/io/test.rs b/src/libstd/io/test.rs
new file mode 100644
index 00000000000..4be11227965
--- /dev/null
+++ b/src/libstd/io/test.rs
@@ -0,0 +1,195 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_escape];
+
+use os;
+use prelude::*;
+use rand;
+use rand::Rng;
+use std::io::net::ip::*;
+use sync::atomics::{AtomicUint, INIT_ATOMIC_UINT, Relaxed};
+
+macro_rules! iotest (
+    { fn $name:ident() $b:block } => (
+        mod $name {
+            #[allow(unused_imports)];
+
+            use super::super::*;
+            use super::*;
+            use io;
+            use prelude::*;
+            use io::*;
+            use io::fs::*;
+            use io::net::tcp::*;
+            use io::net::ip::*;
+            use io::net::udp::*;
+            #[cfg(unix)]
+            use io::net::unix::*;
+            use str;
+            use util;
+
+            fn f() $b
+
+            #[test] fn green() { f() }
+            #[test] fn native() {
+                use native;
+                let (p, c) = Chan::new();
+                do native::task::spawn { c.send(f()) }
+                p.recv();
+            }
+        }
+    )
+)
+
+/// Get a port number, starting at 9600, for use in tests
+pub fn next_test_port() -> u16 {
+    static mut next_offset: AtomicUint = INIT_ATOMIC_UINT;
+    unsafe {
+        base_port() + next_offset.fetch_add(1, Relaxed) as u16
+    }
+}
+
+/// Get a temporary path which could be the location of a unix socket
+pub fn next_test_unix() -> Path {
+    if cfg!(unix) {
+        os::tmpdir().join(rand::task_rng().gen_ascii_str(20))
+    } else {
+        Path::new(r"\\.\pipe\" + rand::task_rng().gen_ascii_str(20))
+    }
+}
+
+/// Get a unique IPv4 localhost:port pair starting at 9600
+pub fn next_test_ip4() -> SocketAddr {
+    SocketAddr { ip: Ipv4Addr(127, 0, 0, 1), port: next_test_port() }
+}
+
+/// Get a unique IPv6 localhost:port pair starting at 9600
+pub fn next_test_ip6() -> SocketAddr {
+    SocketAddr { ip: Ipv6Addr(0, 0, 0, 0, 0, 0, 0, 1), port: next_test_port() }
+}
+
+/*
+XXX: Welcome to MegaHack City.
+
+The bots run multiple builds at the same time, and these builds
+all want to use ports. This function figures out which workspace
+it is running in and assigns a port range based on it.
+*/
+fn base_port() -> u16 {
+
+    let base = 9600u16;
+    let range = 1000u16;
+
+    let bases = [
+        ("32-opt", base + range * 1),
+        ("32-noopt", base + range * 2),
+        ("64-opt", base + range * 3),
+        ("64-noopt", base + range * 4),
+        ("64-opt-vg", base + range * 5),
+        ("all-opt", base + range * 6),
+        ("snap3", base + range * 7),
+        ("dist", base + range * 8)
+    ];
+
+    // FIXME (#9639): This needs to handle non-utf8 paths
+    let path = os::getcwd();
+    let path_s = path.as_str().unwrap();
+
+    let mut final_base = base;
+
+    for &(dir, base) in bases.iter() {
+        if path_s.contains(dir) {
+            final_base = base;
+            break;
+        }
+    }
+
+    return final_base;
+}
+
+pub fn raise_fd_limit() {
+    unsafe { darwin_fd_limit::raise_fd_limit() }
+}
+
+#[cfg(target_os="macos")]
+#[allow(non_camel_case_types)]
+mod darwin_fd_limit {
+    /*!
+     * darwin_fd_limit exists to work around an issue where launchctl on Mac OS X defaults the
+     * rlimit maxfiles to 256/unlimited. The default soft limit of 256 ends up being far too low
+     * for our multithreaded scheduler testing, depending on the number of cores available.
+     *
+     * This fixes issue #7772.
+     */
+
+    use libc;
+    type rlim_t = libc::uint64_t;
+    struct rlimit {
+        rlim_cur: rlim_t,
+        rlim_max: rlim_t
+    }
+    #[nolink]
+    extern {
+        // name probably doesn't need to be mut, but the C function doesn't specify const
+        fn sysctl(name: *mut libc::c_int, namelen: libc::c_uint,
+                  oldp: *mut libc::c_void, oldlenp: *mut libc::size_t,
+                  newp: *mut libc::c_void, newlen: libc::size_t) -> libc::c_int;
+        fn getrlimit(resource: libc::c_int, rlp: *mut rlimit) -> libc::c_int;
+        fn setrlimit(resource: libc::c_int, rlp: *rlimit) -> libc::c_int;
+    }
+    static CTL_KERN: libc::c_int = 1;
+    static KERN_MAXFILESPERPROC: libc::c_int = 29;
+    static RLIMIT_NOFILE: libc::c_int = 8;
+
+    pub unsafe fn raise_fd_limit() {
+        // The strategy here is to fetch the current resource limits, read the kern.maxfilesperproc
+        // sysctl value, and bump the soft resource limit for maxfiles up to the sysctl value.
+        use ptr::{to_unsafe_ptr, to_mut_unsafe_ptr, mut_null};
+        use mem::size_of_val;
+        use os::last_os_error;
+
+        // Fetch the kern.maxfilesperproc value
+        let mut mib: [libc::c_int, ..2] = [CTL_KERN, KERN_MAXFILESPERPROC];
+        let mut maxfiles: libc::c_int = 0;
+        let mut size: libc::size_t = size_of_val(&maxfiles) as libc::size_t;
+        if sysctl(to_mut_unsafe_ptr(&mut mib[0]), 2,
+                  to_mut_unsafe_ptr(&mut maxfiles) as *mut libc::c_void,
+                  to_mut_unsafe_ptr(&mut size),
+                  mut_null(), 0) != 0 {
+            let err = last_os_error();
+            error!("raise_fd_limit: error calling sysctl: {}", err);
+            return;
+        }
+
+        // Fetch the current resource limits
+        let mut rlim = rlimit{rlim_cur: 0, rlim_max: 0};
+        if getrlimit(RLIMIT_NOFILE, to_mut_unsafe_ptr(&mut rlim)) != 0 {
+            let err = last_os_error();
+            error!("raise_fd_limit: error calling getrlimit: {}", err);
+            return;
+        }
+
+        // Bump the soft limit to the smaller of kern.maxfilesperproc and the hard limit
+        rlim.rlim_cur = ::cmp::min(maxfiles as rlim_t, rlim.rlim_max);
+
+        // Set our newly-increased resource limit
+        if setrlimit(RLIMIT_NOFILE, to_unsafe_ptr(&rlim)) != 0 {
+            let err = last_os_error();
+            error!("raise_fd_limit: error calling setrlimit: {}", err);
+            return;
+        }
+    }
+}
+
+#[cfg(not(target_os="macos"))]
+mod darwin_fd_limit {
+    pub unsafe fn raise_fd_limit() {}
+}
diff --git a/src/libstd/io/timer.rs b/src/libstd/io/timer.rs
index 9d4a72509e7..7c9aa28bfe9 100644
--- a/src/libstd/io/timer.rs
+++ b/src/libstd/io/timer.rs
@@ -39,9 +39,7 @@ loop {
 */
 
 use comm::Port;
-use option::{Option, Some, None};
-use result::{Ok, Err};
-use io::io_error;
+use option::Option;
 use rt::rtio::{IoFactory, LocalIo, RtioTimer};
 
 pub struct Timer {
@@ -60,15 +58,7 @@ impl Timer {
     /// for a number of milliseconds, or to possibly create channels which will
     /// get notified after an amount of time has passed.
     pub fn new() -> Option<Timer> {
-        let mut io = LocalIo::borrow();
-        match io.get().timer_init() {
-            Ok(t) => Some(Timer { obj: t }),
-            Err(ioerr) => {
-                debug!("Timer::init: failed to init: {:?}", ioerr);
-                io_error::cond.raise(ioerr);
-                None
-            }
-        }
+        LocalIo::maybe_raise(|io| io.timer_init().map(|t| Timer { obj: t }))
     }
 
     /// Blocks the current task for `msecs` milliseconds.
@@ -108,77 +98,60 @@ impl Timer {
 mod test {
     use prelude::*;
     use super::*;
-    use rt::test::*;
 
     #[test]
     fn test_io_timer_sleep_simple() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            timer.sleep(1);
-        }
+        let mut timer = Timer::new().unwrap();
+        timer.sleep(1);
     }
 
     #[test]
     fn test_io_timer_sleep_oneshot() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            timer.oneshot(1).recv();
-        }
+        let mut timer = Timer::new().unwrap();
+        timer.oneshot(1).recv();
     }
 
     #[test]
     fn test_io_timer_sleep_oneshot_forget() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            timer.oneshot(100000000000);
-        }
+        let mut timer = Timer::new().unwrap();
+        timer.oneshot(100000000000);
     }
 
     #[test]
     fn oneshot_twice() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            let port1 = timer.oneshot(10000);
-            let port = timer.oneshot(1);
-            port.recv();
-            assert_eq!(port1.try_recv(), None);
-        }
+        let mut timer = Timer::new().unwrap();
+        let port1 = timer.oneshot(10000);
+        let port = timer.oneshot(1);
+        port.recv();
+        assert_eq!(port1.try_recv(), None);
     }
 
     #[test]
     fn test_io_timer_oneshot_then_sleep() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            let port = timer.oneshot(100000000000);
-            timer.sleep(1); // this should invalidate the port
+        let mut timer = Timer::new().unwrap();
+        let port = timer.oneshot(100000000000);
+        timer.sleep(1); // this should invalidate the port
 
-            assert_eq!(port.try_recv(), None);
-        }
+        assert_eq!(port.try_recv(), None);
     }
 
     #[test]
     fn test_io_timer_sleep_periodic() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            let port = timer.periodic(1);
-            port.recv();
-            port.recv();
-            port.recv();
-        }
+        let mut timer = Timer::new().unwrap();
+        let port = timer.periodic(1);
+        port.recv();
+        port.recv();
+        port.recv();
     }
 
     #[test]
     fn test_io_timer_sleep_periodic_forget() {
-        do run_in_mt_newsched_task {
-            let mut timer = Timer::new().unwrap();
-            timer.periodic(100000000000);
-        }
+        let mut timer = Timer::new().unwrap();
+        timer.periodic(100000000000);
     }
 
     #[test]
     fn test_io_timer_sleep_standalone() {
-        do run_in_mt_newsched_task {
-            sleep(1)
-        }
+        sleep(1)
     }
 }
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index b2b856c5c83..4f633a63bab 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -65,13 +65,15 @@
 // When testing libstd, bring in libuv as the I/O backend so tests can print
 // things and all of the std::io tests have an I/O interface to run on top
 // of
-#[cfg(test)] extern mod rustuv = "rustuv#0.9-pre";
+#[cfg(test)] extern mod rustuv = "rustuv";
+#[cfg(test)] extern mod native = "native";
+#[cfg(test)] extern mod green = "green";
 
 // Make extra accessible for benchmarking
-#[cfg(test)] extern mod extra = "extra#0.9-pre";
+#[cfg(test)] extern mod extra = "extra";
 
 // Make std testable by not duplicating lang items. See #2912
-#[cfg(test)] extern mod realstd = "std#0.9-pre";
+#[cfg(test)] extern mod realstd = "std";
 #[cfg(test)] pub use kinds = realstd::kinds;
 #[cfg(test)] pub use ops = realstd::ops;
 #[cfg(test)] pub use cmp = realstd::cmp;
@@ -159,6 +161,7 @@ pub mod trie;
 pub mod task;
 pub mod comm;
 pub mod local_data;
+pub mod sync;
 
 
 /* Runtime and platform support */
diff --git a/src/libstd/local_data.rs b/src/libstd/local_data.rs
index 652aa4d8198..d7e11d2f3a7 100644
--- a/src/libstd/local_data.rs
+++ b/src/libstd/local_data.rs
@@ -432,6 +432,7 @@ mod tests {
     }
 
     #[test]
+    #[allow(dead_code)]
     fn test_tls_overwrite_multiple_types() {
         static str_key: Key<~str> = &Key;
         static box_key: Key<@()> = &Key;
diff --git a/src/libstd/logging.rs b/src/libstd/logging.rs
index dbe8b3247c0..fb83cfdd6ea 100644
--- a/src/libstd/logging.rs
+++ b/src/libstd/logging.rs
@@ -118,26 +118,16 @@ pub static ERROR: u32 = 1;
 /// It is not recommended to call this function directly, rather it should be
 /// invoked through the logging family of macros.
 pub fn log(_level: u32, args: &fmt::Arguments) {
-    unsafe {
-        let optional_task: Option<*mut Task> = Local::try_unsafe_borrow();
-        match optional_task {
-            Some(local) => {
-                // Lazily initialize the local task's logger
-                match (*local).logger {
-                    // Use the available logger if we have one
-                    Some(ref mut logger) => { logger.log(args); }
-                    None => {
-                        let mut logger = StdErrLogger::new();
-                        logger.log(args);
-                        (*local).logger = Some(logger);
-                    }
-                }
-            }
-            // If there's no local task, then always log to stderr
-            None => {
-                let mut logger = StdErrLogger::new();
-                logger.log(args);
-            }
-        }
+    let mut logger = {
+        let mut task = Local::borrow(None::<Task>);
+        task.get().logger.take()
+    };
+
+    if logger.is_none() {
+        logger = Some(StdErrLogger::new());
     }
+    logger.get_mut_ref().log(args);
+
+    let mut task = Local::borrow(None::<Task>);
+    task.get().logger = logger;
 }
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index 8da7c0340f7..8f2f2190885 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -28,8 +28,6 @@
 
 #[allow(missing_doc)];
 
-#[cfg(unix)]
-use c_str::CString;
 use clone::Clone;
 use container::Container;
 #[cfg(target_os = "macos")]
@@ -43,8 +41,7 @@ use ptr;
 use str;
 use to_str;
 use unstable::finally::Finally;
-
-pub use os::consts::*;
+use sync::atomics::{AtomicInt, INIT_ATOMIC_INT, SeqCst};
 
 /// Delegates to the libc close() function, returning the same return value.
 pub fn close(fd: c_int) -> c_int {
@@ -58,6 +55,8 @@ static BUF_BYTES : uint = 2048u;
 
 #[cfg(unix)]
 pub fn getcwd() -> Path {
+    use c_str::CString;
+
     let mut buf = [0 as libc::c_char, ..BUF_BYTES];
     unsafe {
         if libc::getcwd(buf.as_mut_ptr(), buf.len() as size_t).is_null() {
@@ -333,7 +332,7 @@ pub fn pipe() -> Pipe {
 
 /// Returns the proper dll filename for the given basename of a file.
 pub fn dll_filename(base: &str) -> ~str {
-    format!("{}{}{}", DLL_PREFIX, base, DLL_SUFFIX)
+    format!("{}{}{}", consts::DLL_PREFIX, base, consts::DLL_SUFFIX)
 }
 
 /// Optionally returns the filesystem path to the current executable which is
@@ -675,17 +674,26 @@ pub fn last_os_error() -> ~str {
     strerror()
 }
 
+static mut EXIT_STATUS: AtomicInt = INIT_ATOMIC_INT;
+
 /**
  * Sets the process exit code
  *
  * Sets the exit code returned by the process if all supervised tasks
  * terminate successfully (without failing). If the current root task fails
  * and is supervised by the scheduler then any user-specified exit status is
- * ignored and the process exits with the default failure status
+ * ignored and the process exits with the default failure status.
+ *
+ * Note that this is not synchronized against modifications of other threads.
  */
 pub fn set_exit_status(code: int) {
-    use rt;
-    rt::set_exit_status(code);
+    unsafe { EXIT_STATUS.store(code, SeqCst) }
+}
+
+/// Fetches the process's current exit code. This defaults to 0 and can change
+/// by calling `set_exit_status`.
+pub fn get_exit_status() -> int {
+    unsafe { EXIT_STATUS.load(SeqCst) }
 }
 
 #[cfg(target_os = "macos")]
diff --git a/src/libstd/rt/borrowck.rs b/src/libstd/rt/borrowck.rs
index 423981d9e91..d1e97cb6ec0 100644
--- a/src/libstd/rt/borrowck.rs
+++ b/src/libstd/rt/borrowck.rs
@@ -12,9 +12,8 @@ use c_str::{ToCStr, CString};
 use libc::{c_char, size_t};
 use option::{Option, None, Some};
 use ptr::RawPtr;
-use rt::env;
+use rt;
 use rt::local::Local;
-use rt::task;
 use rt::task::Task;
 use str::OwnedStr;
 use str;
@@ -62,7 +61,7 @@ unsafe fn fail_borrowed(alloc: *mut raw::Box<()>, file: *c_char, line: size_t)
     match try_take_task_borrow_list() {
         None => { // not recording borrows
             let msg = "borrowed";
-            msg.with_c_str(|msg_p| task::begin_unwind_raw(msg_p, file, line))
+            msg.with_c_str(|msg_p| rt::begin_unwind_raw(msg_p, file, line))
         }
         Some(borrow_list) => { // recording borrows
             let mut msg = ~"borrowed";
@@ -76,7 +75,7 @@ unsafe fn fail_borrowed(alloc: *mut raw::Box<()>, file: *c_char, line: size_t)
                     sep = " and at ";
                 }
             }
-            msg.with_c_str(|msg_p| task::begin_unwind_raw(msg_p, file, line))
+            msg.with_c_str(|msg_p| rt::begin_unwind_raw(msg_p, file, line))
         }
     }
 }
@@ -95,7 +94,7 @@ unsafe fn debug_borrow<T,P:RawPtr<T>>(tag: &'static str,
     //! A useful debugging function that prints a pointer + tag + newline
     //! without allocating memory.
 
-    if ENABLE_DEBUG && env::debug_borrow() {
+    if ENABLE_DEBUG && rt::env::debug_borrow() {
         debug_borrow_slow(tag, p, old_bits, new_bits, filename, line);
     }
 
@@ -180,7 +179,7 @@ pub unsafe fn unrecord_borrow(a: *u8,
             if br.alloc != a || br.file != file || br.line != line {
                 let err = format!("wrong borrow found, br={:?}", br);
                 err.with_c_str(|msg_p| {
-                    task::begin_unwind_raw(msg_p, file, line)
+                    rt::begin_unwind_raw(msg_p, file, line)
                 })
             }
             borrow_list
diff --git a/src/libstd/rt/crate_map.rs b/src/libstd/rt/crate_map.rs
index 22fc3f0ab56..d9b40cfbb6e 100644
--- a/src/libstd/rt/crate_map.rs
+++ b/src/libstd/rt/crate_map.rs
@@ -30,7 +30,7 @@ pub struct CrateMap<'a> {
     version: i32,
     entries: &'a [ModEntry<'a>],
     children: &'a [&'a CrateMap<'a>],
-    event_loop_factory: Option<extern "C" fn() -> ~EventLoop>,
+    event_loop_factory: Option<fn() -> ~EventLoop>,
 }
 
 #[cfg(not(windows))]
diff --git a/src/libstd/rt/env.rs b/src/libstd/rt/env.rs
index d1bd450afe2..f3fa482b18c 100644
--- a/src/libstd/rt/env.rs
+++ b/src/libstd/rt/env.rs
@@ -17,7 +17,7 @@ use os;
 // Note that these are all accessed without any synchronization.
 // They are expected to be initialized once then left alone.
 
-static mut MIN_STACK: uint = 2000000;
+static mut MIN_STACK: uint = 2 * 1024 * 1024;
 static mut DEBUG_BORROW: bool = false;
 static mut POISON_ON_FREE: bool = false;
 
diff --git a/src/libstd/rt/kill.rs b/src/libstd/rt/kill.rs
deleted file mode 100644
index f4f128cf5aa..00000000000
--- a/src/libstd/rt/kill.rs
+++ /dev/null
@@ -1,318 +0,0 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-/*!
-
-Task death: asynchronous killing, linked failure, exit code propagation.
-
-This file implements two orthogonal building-blocks for communicating failure
-between tasks. One is 'linked failure' or 'task killing', that is, a failing
-task causing other tasks to fail promptly (even those that are blocked on
-pipes or I/O). The other is 'exit code propagation', which affects the result
-observed by the parent of a task::try task that itself spawns child tasks
-(such as any #[test] function). In both cases the data structures live in
-KillHandle.
-
-
-I. Task killing.
-
-The model for killing involves two atomic flags, the "kill flag" and the
-"unkillable flag". Operations on the kill flag include:
-
-- In the taskgroup code (task/spawn.rs), tasks store a clone of their
-  KillHandle in their shared taskgroup. Another task in the group that fails
-  will use that handle to call kill().
-- When a task blocks, it turns its ~Task into a BlockedTask by storing a
-  the transmuted ~Task pointer inside the KillHandle's kill flag. A task
-  trying to block and a task trying to kill it can simultaneously access the
-  kill flag, after which the task will get scheduled and fail (no matter who
-  wins the race). Likewise, a task trying to wake a blocked task normally and
-  a task trying to kill it can simultaneously access the flag; only one will
-  get the task to reschedule it.
-
-Operations on the unkillable flag include:
-
-- When a task becomes unkillable, it swaps on the flag to forbid any killer
-  from waking it up while it's blocked inside the unkillable section. If a
-  kill was already pending, the task fails instead of becoming unkillable.
-- When a task is done being unkillable, it restores the flag to the normal
-  running state. If a kill was received-but-blocked during the unkillable
-  section, the task fails at this later point.
-- When a task tries to kill another task, before swapping on the kill flag, it
-  first swaps on the unkillable flag, to see if it's "allowed" to wake up the
-  task. If it isn't, the killed task will receive the signal when it becomes
-  killable again. (Of course, a task trying to wake the task normally (e.g.
-  sending on a channel) does not access the unkillable flag at all.)
-
-Why do we not need acquire/release barriers on any of the kill flag swaps?
-This is because barriers establish orderings between accesses on different
-memory locations, but each kill-related operation is only a swap on a single
-location, so atomicity is all that matters. The exception is kill(), which
-does a swap on both flags in sequence. kill() needs no barriers because it
-does not matter if its two accesses are seen reordered on another CPU: if a
-killer does perform both writes, it means it saw a KILL_RUNNING in the
-unkillable flag, which means an unkillable task will see KILL_KILLED and fail
-immediately (rendering the subsequent write to the kill flag unnecessary).
-
-
-II. Exit code propagation.
-
-The basic model for exit code propagation, which is used with the "watched"
-spawn mode (on by default for linked spawns, off for supervised and unlinked
-spawns), is that a parent will wait for all its watched children to exit
-before reporting whether it succeeded or failed. A watching parent will only
-report success if it succeeded and all its children also reported success;
-otherwise, it will report failure. This is most useful for writing test cases:
-
- ```
-#[test]
-fn test_something_in_another_task {
-    do spawn {
-        assert!(collatz_conjecture_is_false());
-    }
-}
- ```
-
-Here, as the child task will certainly outlive the parent task, we might miss
-the failure of the child when deciding whether or not the test case passed.
-The watched spawn mode avoids this problem.
-
-In order to propagate exit codes from children to their parents, any
-'watching' parent must wait for all of its children to exit before it can
-report its final exit status. We achieve this by using an UnsafeArc, using the
-reference counting to track how many children are still alive, and using the
-unwrap() operation in the parent's exit path to wait for all children to exit.
-The UnsafeArc referred to here is actually the KillHandle itself.
-
-This also works transitively, as if a "middle" watched child task is itself
-watching a grandchild task, the "middle" task will do unwrap() on its own
-KillHandle (thereby waiting for the grandchild to exit) before dropping its
-reference to its watching parent (which will alert the parent).
-
-While UnsafeArc::unwrap() accomplishes the synchronization, there remains the
-matter of reporting the exit codes themselves. This is easiest when an exiting
-watched task has no watched children of its own:
-
-- If the task with no watched children exits successfully, it need do nothing.
-- If the task with no watched children has failed, it sets a flag in the
-  parent's KillHandle ("any_child_failed") to false. It then stays false forever.
-
-However, if a "middle" watched task with watched children of its own exits
-before its child exits, we need to ensure that the grandparent task may still
-see a failure from the grandchild task. While we could achieve this by having
-each intermediate task block on its handle, this keeps around the other resources
-the task was using. To be more efficient, this is accomplished via "tombstones".
-
-A tombstone is a closure, proc() -> bool, which will perform any waiting necessary
-to collect the exit code of descendant tasks. In its environment is captured
-the KillHandle of whichever task created the tombstone, and perhaps also any
-tombstones that that task itself had, and finally also another tombstone,
-effectively creating a lazy-list of heap closures.
-
-When a child wishes to exit early and leave tombstones behind for its parent,
-it must use a LittleLock (pthread mutex) to synchronize with any possible
-sibling tasks which are trying to do the same thing with the same parent.
-However, on the other side, when the parent is ready to pull on the tombstones,
-it need not use this lock, because the unwrap() serves as a barrier that ensures
-no children will remain with references to the handle.
-
-The main logic for creating and assigning tombstones can be found in the
-function reparent_children_to() in the impl for KillHandle.
-
-
-IIA. Issues with exit code propagation.
-
-There are two known issues with the current scheme for exit code propagation.
-
-- As documented in issue #8136, the structure mandates the possibility for stack
-  overflow when collecting tombstones that are very deeply nested. This cannot
-  be avoided with the closure representation, as tombstones end up structured in
-  a sort of tree. However, notably, the tombstones do not actually need to be
-  collected in any particular order, and so a doubly-linked list may be used.
-  However we do not do this yet because DList is in libextra.
-
-- A discussion with Graydon made me realize that if we decoupled the exit code
-  propagation from the parents-waiting action, this could result in a simpler
-  implementation as the exit codes themselves would not have to be propagated,
-  and could instead be propagated implicitly through the taskgroup mechanism
-  that we already have. The tombstoning scheme would still be required. I have
-  not implemented this because currently we can't receive a linked failure kill
-  signal during the task cleanup activity, as that is currently "unkillable",
-  and occurs outside the task's unwinder's "try" block, so would require some
-  restructuring.
-
-*/
-
-use cast;
-use option::{Option, Some, None};
-use prelude::*;
-use iter;
-use task::TaskResult;
-use rt::task::Task;
-use unstable::atomics::{AtomicUint, SeqCst};
-use unstable::sync::UnsafeArc;
-
-/// A handle to a blocked task. Usually this means having the ~Task pointer by
-/// ownership, but if the task is killable, a killer can steal it at any time.
-pub enum BlockedTask {
-    Owned(~Task),
-    Shared(UnsafeArc<AtomicUint>),
-}
-
-/// Per-task state related to task death, killing, failure, etc.
-pub struct Death {
-    // Action to be done with the exit code. If set, also makes the task wait
-    // until all its watched children exit before collecting the status.
-    on_exit:         Option<proc(TaskResult)>,
-    // nesting level counter for unstable::atomically calls (0 == can deschedule).
-    priv wont_sleep:      int,
-}
-
-pub struct BlockedTaskIterator {
-    priv inner: UnsafeArc<AtomicUint>,
-}
-
-impl Iterator<BlockedTask> for BlockedTaskIterator {
-    fn next(&mut self) -> Option<BlockedTask> {
-        Some(Shared(self.inner.clone()))
-    }
-}
-
-impl BlockedTask {
-    /// Returns Some if the task was successfully woken; None if already killed.
-    pub fn wake(self) -> Option<~Task> {
-        match self {
-            Owned(task) => Some(task),
-            Shared(arc) => unsafe {
-                match (*arc.get()).swap(0, SeqCst) {
-                    0 => None,
-                    n => cast::transmute(n),
-                }
-            }
-        }
-    }
-
-    /// Create a blocked task, unless the task was already killed.
-    pub fn block(task: ~Task) -> BlockedTask {
-        Owned(task)
-    }
-
-    /// Converts one blocked task handle to a list of many handles to the same.
-    pub fn make_selectable(self, num_handles: uint)
-        -> iter::Take<BlockedTaskIterator>
-    {
-        let arc = match self {
-            Owned(task) => {
-                let flag = unsafe { AtomicUint::new(cast::transmute(task)) };
-                UnsafeArc::new(flag)
-            }
-            Shared(arc) => arc.clone(),
-        };
-        BlockedTaskIterator{ inner: arc }.take(num_handles)
-    }
-
-    // This assertion has two flavours because the wake involves an atomic op.
-    // In the faster version, destructors will fail dramatically instead.
-    #[inline] #[cfg(not(test))]
-    pub fn assert_already_awake(self) { }
-    #[inline] #[cfg(test)]
-    pub fn assert_already_awake(self) { assert!(self.wake().is_none()); }
-
-    /// Convert to an unsafe uint value. Useful for storing in a pipe's state flag.
-    #[inline]
-    pub unsafe fn cast_to_uint(self) -> uint {
-        match self {
-            Owned(task) => {
-                let blocked_task_ptr: uint = cast::transmute(task);
-                rtassert!(blocked_task_ptr & 0x1 == 0);
-                blocked_task_ptr
-            }
-            Shared(arc) => {
-                let blocked_task_ptr: uint = cast::transmute(~arc);
-                rtassert!(blocked_task_ptr & 0x1 == 0);
-                blocked_task_ptr | 0x1
-            }
-        }
-    }
-
-    /// Convert from an unsafe uint value. Useful for retrieving a pipe's state flag.
-    #[inline]
-    pub unsafe fn cast_from_uint(blocked_task_ptr: uint) -> BlockedTask {
-        if blocked_task_ptr & 0x1 == 0 {
-            Owned(cast::transmute(blocked_task_ptr))
-        } else {
-            let ptr: ~UnsafeArc<AtomicUint> = cast::transmute(blocked_task_ptr & !1);
-            Shared(*ptr)
-        }
-    }
-}
-
-impl Death {
-    pub fn new() -> Death {
-        Death {
-            on_exit:         None,
-            wont_sleep:      0,
-        }
-    }
-
-    /// Collect failure exit codes from children and propagate them to a parent.
-    pub fn collect_failure(&mut self, result: TaskResult) {
-        match self.on_exit.take() {
-            Some(f) => f(result),
-            None => {}
-        }
-    }
-
-    /// Enter a possibly-nested "atomic" section of code. Just for assertions.
-    /// All calls must be paired with a subsequent call to allow_deschedule.
-    #[inline]
-    pub fn inhibit_deschedule(&mut self) {
-        self.wont_sleep += 1;
-    }
-
-    /// Exit a possibly-nested "atomic" section of code. Just for assertions.
-    /// All calls must be paired with a preceding call to inhibit_deschedule.
-    #[inline]
-    pub fn allow_deschedule(&mut self) {
-        rtassert!(self.wont_sleep != 0);
-        self.wont_sleep -= 1;
-    }
-
-    /// Ensure that the task is allowed to become descheduled.
-    #[inline]
-    pub fn assert_may_sleep(&self) {
-        if self.wont_sleep != 0 {
-            rtabort!("illegal atomic-sleep: attempt to reschedule while \
-                      using an Exclusive or LittleLock");
-        }
-    }
-}
-
-impl Drop for Death {
-    fn drop(&mut self) {
-        // Mustn't be in an atomic or unkillable section at task death.
-        rtassert!(self.wont_sleep == 0);
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use rt::test::*;
-    use super::*;
-
-    // Task blocking tests
-
-    #[test]
-    fn block_and_wake() {
-        do with_test_task |task| {
-            BlockedTask::block(task).wake().unwrap()
-        }
-    }
-}
diff --git a/src/libstd/rt/local.rs b/src/libstd/rt/local.rs
index d73ad98a25b..1c04b6b43ce 100644
--- a/src/libstd/rt/local.rs
+++ b/src/libstd/rt/local.rs
@@ -8,8 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use option::{Option, Some, None};
-use rt::sched::Scheduler;
+use option::Option;
 use rt::task::Task;
 use rt::local_ptr;
 
@@ -46,87 +45,10 @@ impl Local<local_ptr::Borrowed<Task>> for Task {
     }
 }
 
-/// Encapsulates a temporarily-borrowed scheduler.
-pub struct BorrowedScheduler {
-    priv task: local_ptr::Borrowed<Task>,
-}
-
-impl BorrowedScheduler {
-    fn new(mut task: local_ptr::Borrowed<Task>) -> BorrowedScheduler {
-        if task.get().sched.is_none() {
-            rtabort!("no scheduler")
-        } else {
-            BorrowedScheduler {
-                task: task,
-            }
-        }
-    }
-
-    #[inline]
-    pub fn get<'a>(&'a mut self) -> &'a mut ~Scheduler {
-        match self.task.get().sched {
-            None => rtabort!("no scheduler"),
-            Some(ref mut sched) => sched,
-        }
-    }
-}
-
-impl Local<BorrowedScheduler> for Scheduler {
-    fn put(value: ~Scheduler) {
-        let mut task = Local::borrow(None::<Task>);
-        task.get().sched = Some(value);
-    }
-    #[inline]
-    fn take() -> ~Scheduler {
-        unsafe {
-            // XXX: Unsafe for speed
-            let task: *mut Task = Local::unsafe_borrow();
-            (*task).sched.take_unwrap()
-        }
-    }
-    fn exists(_: Option<Scheduler>) -> bool {
-        let mut task = Local::borrow(None::<Task>);
-        task.get().sched.is_some()
-    }
-    #[inline]
-    fn borrow(_: Option<Scheduler>) -> BorrowedScheduler {
-        BorrowedScheduler::new(Local::borrow(None::<Task>))
-    }
-    unsafe fn unsafe_take() -> ~Scheduler { rtabort!("unimpl") }
-    unsafe fn unsafe_borrow() -> *mut Scheduler {
-        let task: *mut Task = Local::unsafe_borrow();
-        match (*task).sched {
-            Some(~ref mut sched) => {
-                let s: *mut Scheduler = &mut *sched;
-                return s;
-            }
-            None => {
-                rtabort!("no scheduler")
-            }
-        }
-    }
-    unsafe fn try_unsafe_borrow() -> Option<*mut Scheduler> {
-        let task_opt: Option<*mut Task> = Local::try_unsafe_borrow();
-        match task_opt {
-            Some(task) => {
-                match (*task).sched {
-                    Some(~ref mut sched) => {
-                        let s: *mut Scheduler = &mut *sched;
-                        Some(s)
-                    }
-                    None => None
-                }
-            }
-            None => None
-        }
-    }
-}
-
 #[cfg(test)]
 mod test {
     use option::None;
     use unstable::run_in_bare_thread;
-    use rt::test::*;
     use super::*;
     use rt::task::Task;
     use rt::local_ptr;
@@ -135,8 +57,7 @@ mod test {
     fn thread_local_task_smoke_test() {
         do run_in_bare_thread {
             local_ptr::init();
-            let mut sched = ~new_test_uv_sched();
-            let task = ~Task::new_root(&mut sched.stack_pool, None, proc(){});
+            let task = ~Task::new();
             Local::put(task);
             let task: ~Task = Local::take();
             cleanup_task(task);
@@ -147,12 +68,11 @@ mod test {
     fn thread_local_task_two_instances() {
         do run_in_bare_thread {
             local_ptr::init();
-            let mut sched = ~new_test_uv_sched();
-            let task = ~Task::new_root(&mut sched.stack_pool, None, proc(){});
+            let task = ~Task::new();
             Local::put(task);
             let task: ~Task = Local::take();
             cleanup_task(task);
-            let task = ~Task::new_root(&mut sched.stack_pool, None, proc(){});
+            let task = ~Task::new();
             Local::put(task);
             let task: ~Task = Local::take();
             cleanup_task(task);
@@ -164,8 +84,7 @@ mod test {
     fn borrow_smoke_test() {
         do run_in_bare_thread {
             local_ptr::init();
-            let mut sched = ~new_test_uv_sched();
-            let task = ~Task::new_root(&mut sched.stack_pool, None, proc(){});
+            let task = ~Task::new();
             Local::put(task);
 
             unsafe {
@@ -180,8 +99,7 @@ mod test {
     fn borrow_with_return() {
         do run_in_bare_thread {
             local_ptr::init();
-            let mut sched = ~new_test_uv_sched();
-            let task = ~Task::new_root(&mut sched.stack_pool, None, proc(){});
+            let task = ~Task::new();
             Local::put(task);
 
             {
@@ -193,5 +111,9 @@ mod test {
         }
     }
 
+    fn cleanup_task(mut t: ~Task) {
+        t.destroyed = true;
+    }
+
 }
 
diff --git a/src/libstd/rt/local_ptr.rs b/src/libstd/rt/local_ptr.rs
index 925aa802ad5..42cce272e44 100644
--- a/src/libstd/rt/local_ptr.rs
+++ b/src/libstd/rt/local_ptr.rs
@@ -42,7 +42,7 @@ impl<T> Drop for Borrowed<T> {
             }
             let val: ~T = cast::transmute(self.val);
             put::<T>(val);
-            assert!(exists());
+            rtassert!(exists());
         }
     }
 }
@@ -109,7 +109,9 @@ pub mod compiled {
     /// Does not validate the pointer type.
     #[inline]
     pub unsafe fn take<T>() -> ~T {
-        let ptr: ~T = cast::transmute(RT_TLS_PTR);
+        let ptr = RT_TLS_PTR;
+        rtassert!(!ptr.is_null());
+        let ptr: ~T = cast::transmute(ptr);
         // can't use `as`, due to type not matching with `cfg(test)`
         RT_TLS_PTR = cast::transmute(0);
         ptr
@@ -178,7 +180,7 @@ pub mod native {
     }
 
     pub unsafe fn cleanup() {
-        assert!(INITIALIZED);
+        rtassert!(INITIALIZED);
         tls::destroy(RT_TLS_KEY);
         LOCK.destroy();
         INITIALIZED = false;
diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index df1ebeb6407..0dd6c883d5b 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -57,27 +57,17 @@ Several modules in `core` are clients of `rt`:
 // XXX: this should not be here.
 #[allow(missing_doc)];
 
+use any::Any;
 use clone::Clone;
 use container::Container;
 use iter::Iterator;
-use option::{Option, None, Some};
+use option::Option;
 use ptr::RawPtr;
-use rt::local::Local;
-use rt::sched::{Scheduler, Shutdown};
-use rt::sleeper_list::SleeperList;
-use task::TaskResult;
-use rt::task::{Task, SchedTask, GreenTask, Sched};
-use send_str::SendStrStatic;
-use unstable::atomics::{AtomicInt, AtomicBool, SeqCst};
-use unstable::sync::UnsafeArc;
+use result::Result;
+use task::TaskOpts;
 use vec::{OwnedVector, MutableVector, ImmutableVector};
-use vec;
 
-use self::thread::Thread;
-
-// the os module needs to reach into this helper, so allow general access
-// through this reexport.
-pub use self::util::set_exit_status;
+use self::task::{Task, BlockedTask};
 
 // this is somewhat useful when a program wants to spawn a "reasonable" number
 // of workers based on the constraints of the system that it's running on.
@@ -85,8 +75,8 @@ pub use self::util::set_exit_status;
 // method...
 pub use self::util::default_sched_threads;
 
-// Re-export of the functionality in the kill module
-pub use self::kill::BlockedTask;
+// Export unwinding facilities used by the failure macros
+pub use self::unwind::{begin_unwind, begin_unwind_raw};
 
 // XXX: these probably shouldn't be public...
 #[doc(hidden)]
@@ -99,21 +89,12 @@ pub mod shouldnt_be_public {
 // Internal macros used by the runtime.
 mod macros;
 
-/// Basic implementation of an EventLoop, provides no I/O interfaces
-mod basic;
-
 /// The global (exchange) heap.
 pub mod global_heap;
 
 /// Implementations of language-critical runtime features like @.
 pub mod task;
 
-/// Facilities related to task failure, killing, and death.
-mod kill;
-
-/// The coroutine task scheduler, built on the `io` event loop.
-pub mod sched;
-
 /// The EventLoop and internal synchronous I/O interface.
 pub mod rtio;
 
@@ -121,27 +102,6 @@ pub mod rtio;
 /// or task-local storage.
 pub mod local;
 
-/// A mostly lock-free multi-producer, single consumer queue.
-pub mod mpsc_queue;
-
-/// A lock-free single-producer, single consumer queue.
-pub mod spsc_queue;
-
-/// A lock-free multi-producer, multi-consumer bounded queue.
-mod mpmc_bounded_queue;
-
-/// A parallel work-stealing deque
-pub mod deque;
-
-/// A parallel data structure for tracking sleeping schedulers.
-pub mod sleeper_list;
-
-/// Stack segments and caching.
-pub mod stack;
-
-/// CPU context swapping.
-mod context;
-
 /// Bindings to system threading libraries.
 pub mod thread;
 
@@ -157,16 +117,6 @@ pub mod logging;
 /// Crate map
 pub mod crate_map;
 
-/// Tools for testing the runtime
-pub mod test;
-
-/// Reference counting
-pub mod rc;
-
-/// A simple single-threaded channel type for passing buffered data between
-/// scheduler and task context
-pub mod tube;
-
 /// The runtime needs to be able to put a pointer into thread-local storage.
 mod local_ptr;
 
@@ -185,41 +135,33 @@ pub mod args;
 // Support for dynamic borrowck
 pub mod borrowck;
 
-/// Set up a default runtime configuration, given compiler-supplied arguments.
-///
-/// This is invoked by the `start` _language item_ (unstable::lang) to
-/// run a Rust executable.
-///
-/// # Arguments
-///
-/// * `argc` & `argv` - The argument vector. On Unix this information is used
-///   by os::args.
-///
-/// # Return value
-///
-/// The return value is used as the process return code. 0 on success, 101 on error.
-pub fn start(argc: int, argv: **u8, main: proc()) -> int {
+/// The default error code of the rust runtime if the main task fails instead
+/// of exiting cleanly.
+pub static DEFAULT_ERROR_CODE: int = 101;
 
-    init(argc, argv);
-    let exit_code = run(main);
-    // unsafe is ok b/c we're sure that the runtime is gone
-    unsafe { cleanup(); }
-
-    return exit_code;
-}
-
-/// Like `start` but creates an additional scheduler on the current thread,
-/// which in most cases will be the 'main' thread, and pins the main task to it.
+/// The interface to the current runtime.
 ///
-/// This is appropriate for running code that must execute on the main thread,
-/// such as the platform event loop and GUI.
-pub fn start_on_main_thread(argc: int, argv: **u8, main: proc()) -> int {
-    init(argc, argv);
-    let exit_code = run_on_main_thread(main);
-    // unsafe is ok b/c we're sure that the runtime is gone
-    unsafe { cleanup(); }
+/// This trait is used as the abstraction between 1:1 and M:N scheduling. The
+/// two independent crates, libnative and libgreen, both have objects which
+/// implement this trait. The goal of this trait is to encompass all the
+/// fundamental differences in functionality between the 1:1 and M:N runtime
+/// modes.
+pub trait Runtime {
+    // Necessary scheduling functions, used for channels and blocking I/O
+    // (sometimes).
+    fn yield_now(~self, cur_task: ~Task);
+    fn maybe_yield(~self, cur_task: ~Task);
+    fn deschedule(~self, times: uint, cur_task: ~Task,
+                  f: |BlockedTask| -> Result<(), BlockedTask>);
+    fn reawaken(~self, to_wake: ~Task, can_resched: bool);
 
-    return exit_code;
+    // Miscellaneous calls which are very different depending on what context
+    // you're in.
+    fn spawn_sibling(~self, cur_task: ~Task, opts: TaskOpts, f: proc());
+    fn local_io<'a>(&'a mut self) -> Option<rtio::LocalIo<'a>>;
+
+    // XXX: This is a serious code smell and this should not exist at all.
+    fn wrap(~self) -> ~Any;
 }
 
 /// One-time runtime initialization.
@@ -234,6 +176,7 @@ pub fn init(argc: int, argv: **u8) {
         args::init(argc, argv);
         env::init();
         logging::init();
+        local_ptr::init();
     }
 }
 
@@ -250,239 +193,3 @@ pub unsafe fn cleanup() {
     args::cleanup();
     local_ptr::cleanup();
 }
-
-/// Execute the main function in a scheduler.
-///
-/// Configures the runtime according to the environment, by default
-/// using a task scheduler with the same number of threads as cores.
-/// Returns a process exit code.
-pub fn run(main: proc()) -> int {
-    run_(main, false)
-}
-
-pub fn run_on_main_thread(main: proc()) -> int {
-    run_(main, true)
-}
-
-fn run_(main: proc(), use_main_sched: bool) -> int {
-    static DEFAULT_ERROR_CODE: int = 101;
-
-    let nscheds = util::default_sched_threads();
-
-    let mut main = Some(main);
-
-    // The shared list of sleeping schedulers.
-    let sleepers = SleeperList::new();
-
-    // Create a work queue for each scheduler, ntimes. Create an extra
-    // for the main thread if that flag is set. We won't steal from it.
-    let mut pool = deque::BufferPool::new();
-    let arr = vec::from_fn(nscheds, |_| pool.deque());
-    let (workers, stealers) = vec::unzip(arr.move_iter());
-
-    // The schedulers.
-    let mut scheds = ~[];
-    // Handles to the schedulers. When the main task ends these will be
-    // sent the Shutdown message to terminate the schedulers.
-    let mut handles = ~[];
-
-    for worker in workers.move_iter() {
-        rtdebug!("inserting a regular scheduler");
-
-        // Every scheduler is driven by an I/O event loop.
-        let loop_ = new_event_loop();
-        let mut sched = ~Scheduler::new(loop_,
-                                        worker,
-                                        stealers.clone(),
-                                        sleepers.clone());
-        let handle = sched.make_handle();
-
-        scheds.push(sched);
-        handles.push(handle);
-    }
-
-    // If we need a main-thread task then create a main thread scheduler
-    // that will reject any task that isn't pinned to it
-    let main_sched = if use_main_sched {
-
-        // Create a friend handle.
-        let mut friend_sched = scheds.pop();
-        let friend_handle = friend_sched.make_handle();
-        scheds.push(friend_sched);
-
-        // This scheduler needs a queue that isn't part of the stealee
-        // set.
-        let (worker, _) = pool.deque();
-
-        let main_loop = new_event_loop();
-        let mut main_sched = ~Scheduler::new_special(main_loop,
-                                                     worker,
-                                                     stealers.clone(),
-                                                     sleepers.clone(),
-                                                     false,
-                                                     Some(friend_handle));
-        let mut main_handle = main_sched.make_handle();
-        // Allow the scheduler to exit when the main task exits.
-        // Note: sending the shutdown message also prevents the scheduler
-        // from pushing itself to the sleeper list, which is used for
-        // waking up schedulers for work stealing; since this is a
-        // non-work-stealing scheduler it should not be adding itself
-        // to the list.
-        main_handle.send(Shutdown);
-        Some(main_sched)
-    } else {
-        None
-    };
-
-    // Create a shared cell for transmitting the process exit
-    // code from the main task to this function.
-    let exit_code = UnsafeArc::new(AtomicInt::new(0));
-    let exit_code_clone = exit_code.clone();
-
-    // Used to sanity check that the runtime only exits once
-    let exited_already = UnsafeArc::new(AtomicBool::new(false));
-
-    // When the main task exits, after all the tasks in the main
-    // task tree, shut down the schedulers and set the exit code.
-    let handles = handles;
-    let on_exit: proc(TaskResult) = proc(exit_success) {
-        unsafe {
-            assert!(!(*exited_already.get()).swap(true, SeqCst),
-                    "the runtime already exited");
-        }
-
-        let mut handles = handles;
-        for handle in handles.mut_iter() {
-            handle.send(Shutdown);
-        }
-
-        unsafe {
-            let exit_code = if exit_success.is_ok() {
-                use rt::util;
-
-                // If we're exiting successfully, then return the global
-                // exit status, which can be set programmatically.
-                util::get_exit_status()
-            } else {
-                DEFAULT_ERROR_CODE
-            };
-            (*exit_code_clone.get()).store(exit_code, SeqCst);
-        }
-    };
-
-    let mut threads = ~[];
-    let mut on_exit = Some(on_exit);
-
-    if !use_main_sched {
-
-        // In the case where we do not use a main_thread scheduler we
-        // run the main task in one of our threads.
-
-        let mut main_task = ~Task::new_root(&mut scheds[0].stack_pool,
-                                            None,
-                                            ::util::replace(&mut main,
-                                                            None).unwrap());
-        main_task.name = Some(SendStrStatic("<main>"));
-        main_task.death.on_exit = ::util::replace(&mut on_exit, None);
-
-        let sched = scheds.pop();
-        let main_task = main_task;
-        let thread = do Thread::start {
-            sched.bootstrap(main_task);
-        };
-        threads.push(thread);
-    }
-
-    // Run each remaining scheduler in a thread.
-    for sched in scheds.move_rev_iter() {
-        rtdebug!("creating regular schedulers");
-        let thread = do Thread::start {
-            let mut sched = sched;
-            let bootstrap_task = ~do Task::new_root(&mut sched.stack_pool, None) || {
-                rtdebug!("boostraping a non-primary scheduler");
-            };
-            sched.bootstrap(bootstrap_task);
-        };
-        threads.push(thread);
-    }
-
-    // If we do have a main thread scheduler, run it now.
-
-    if use_main_sched {
-        rtdebug!("about to create the main scheduler task");
-
-        let mut main_sched = main_sched.unwrap();
-
-        let home = Sched(main_sched.make_handle());
-        let mut main_task = ~Task::new_root_homed(&mut main_sched.stack_pool,
-                                                  None,
-                                                  home,
-                                                  ::util::replace(&mut main,
-                                                                  None).
-                                                                  unwrap());
-        main_task.name = Some(SendStrStatic("<main>"));
-        main_task.death.on_exit = ::util::replace(&mut on_exit, None);
-        rtdebug!("bootstrapping main_task");
-
-        main_sched.bootstrap(main_task);
-    }
-
-    rtdebug!("waiting for threads");
-
-    // Wait for schedulers
-    for thread in threads.move_iter() {
-        thread.join();
-    }
-
-    // Return the exit code
-    unsafe {
-        (*exit_code.get()).load(SeqCst)
-    }
-}
-
-pub fn in_sched_context() -> bool {
-    unsafe {
-        let task_ptr: Option<*mut Task> = Local::try_unsafe_borrow();
-        match task_ptr {
-            Some(task) => {
-                match (*task).task_type {
-                    SchedTask => true,
-                    _ => false
-                }
-            }
-            None => false
-        }
-    }
-}
-
-pub fn in_green_task_context() -> bool {
-    unsafe {
-        let task: Option<*mut Task> = Local::try_unsafe_borrow();
-        match task {
-            Some(task) => {
-                match (*task).task_type {
-                    GreenTask(_) => true,
-                    _ => false
-                }
-            }
-            None => false
-        }
-    }
-}
-
-pub fn new_event_loop() -> ~rtio::EventLoop {
-    match crate_map::get_crate_map() {
-        None => {}
-        Some(map) => {
-            match map.event_loop_factory {
-                None => {}
-                Some(factory) => return factory()
-            }
-        }
-    }
-
-    // If the crate map didn't specify a factory to create an event loop, then
-    // instead just use a basic event loop missing all I/O services to at least
-    // get the scheduler running.
-    return basic::event_loop();
-}
diff --git a/src/libstd/rt/rc.rs b/src/libstd/rt/rc.rs
deleted file mode 100644
index 2699dab6d38..00000000000
--- a/src/libstd/rt/rc.rs
+++ /dev/null
@@ -1,139 +0,0 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! An owned, task-local, reference counted type
-//!
-//! # Safety note
-//!
-//! XXX There is currently no type-system mechanism for enforcing that
-//! reference counted types are both allocated on the exchange heap
-//! and also non-sendable
-//!
-//! This doesn't prevent borrowing multiple aliasable mutable pointers
-
-use ops::Drop;
-use clone::Clone;
-use libc::c_void;
-use cast;
-
-pub struct RC<T> {
-    priv p: *c_void // ~(uint, T)
-}
-
-impl<T> RC<T> {
-    pub fn new(val: T) -> RC<T> {
-        unsafe {
-            let v = ~(1, val);
-            let p: *c_void = cast::transmute(v);
-            RC { p: p }
-        }
-    }
-
-    fn get_mut_state(&mut self) -> *mut (uint, T) {
-        unsafe {
-            let p: &mut ~(uint, T) = cast::transmute(&mut self.p);
-            let p: *mut (uint, T) = &mut **p;
-            return p;
-        }
-    }
-
-    fn get_state(&self) -> *(uint, T) {
-        unsafe {
-            let p: &~(uint, T) = cast::transmute(&self.p);
-            let p: *(uint, T) = &**p;
-            return p;
-        }
-    }
-
-    pub fn unsafe_borrow_mut(&mut self) -> *mut T {
-        unsafe {
-            match *self.get_mut_state() {
-                (_, ref mut p) => {
-                    let p: *mut T = p;
-                    return p;
-                }
-            }
-        }
-    }
-
-    pub fn refcount(&self) -> uint {
-        unsafe {
-            match *self.get_state() {
-                (count, _) => count
-            }
-        }
-    }
-}
-
-#[unsafe_destructor]
-impl<T> Drop for RC<T> {
-    fn drop(&mut self) {
-        assert!(self.refcount() > 0);
-
-        unsafe {
-            match *self.get_mut_state() {
-                (ref mut count, _) => {
-                    *count = *count - 1
-                }
-            }
-
-            if self.refcount() == 0 {
-                let _: ~(uint, T) = cast::transmute(self.p);
-            }
-        }
-    }
-}
-
-impl<T> Clone for RC<T> {
-    fn clone(&self) -> RC<T> {
-        unsafe {
-            // XXX: Mutable clone
-            let this: &mut RC<T> = cast::transmute_mut(self);
-
-            match *this.get_mut_state() {
-                (ref mut count, _) => {
-                    *count = *count + 1;
-                }
-            }
-        }
-
-        RC { p: self.p }
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::RC;
-
-    #[test]
-    fn smoke_test() {
-        unsafe {
-            let mut v1 = RC::new(100);
-            assert!(*v1.unsafe_borrow_mut() == 100);
-            assert!(v1.refcount() == 1);
-
-            let mut v2 = v1.clone();
-            assert!(*v2.unsafe_borrow_mut() == 100);
-            assert!(v2.refcount() == 2);
-
-            *v2.unsafe_borrow_mut() = 200;
-            assert!(*v2.unsafe_borrow_mut() == 200);
-            assert!(*v1.unsafe_borrow_mut() == 200);
-
-            let v3 = v2.clone();
-            assert!(v3.refcount() == 3);
-            {
-                let _v1 = v1;
-                let _v2 = v2;
-            }
-            assert!(v3.refcount() == 1);
-        }
-    }
-}
diff --git a/src/libstd/rt/rtio.rs b/src/libstd/rt/rtio.rs
index b54231421e3..6b3d50a76ac 100644
--- a/src/libstd/rt/rtio.rs
+++ b/src/libstd/rt/rtio.rs
@@ -14,14 +14,15 @@ use comm::{SharedChan, Port};
 use libc::c_int;
 use libc;
 use ops::Drop;
-use option::*;
+use option::{Option, Some, None};
 use path::Path;
-use result::*;
+use result::{Result, Ok, Err};
+use rt::task::Task;
+use rt::local::Local;
 
 use ai = io::net::addrinfo;
+use io;
 use io::IoError;
-use io::native::NATIVE_IO_FACTORY;
-use io::native;
 use io::net::ip::{IpAddr, SocketAddr};
 use io::process::{ProcessConfig, ProcessExit};
 use io::signal::Signum;
@@ -93,36 +94,52 @@ impl<'a> Drop for LocalIo<'a> {
 impl<'a> LocalIo<'a> {
     /// Returns the local I/O: either the local scheduler's I/O services or
     /// the native I/O services.
-    pub fn borrow() -> LocalIo {
-        use rt::sched::Scheduler;
-        use rt::local::Local;
+    pub fn borrow() -> Option<LocalIo> {
+        // FIXME(#11053): bad
+        //
+        // This is currently very unsafely implemented. We don't actually
+        // *take* the local I/O so there's a very real possibility that we
+        // can have two borrows at once. Currently there is not a clear way
+        // to actually borrow the local I/O factory safely because even if
+        // ownership were transferred down to the functions that the I/O
+        // factory implements it's just too much of a pain to know when to
+        // relinquish ownership back into the local task (but that would be
+        // the safe way of implementing this function).
+        //
+        // In order to get around this, we just transmute a copy out of the task
+        // in order to have what is likely a static lifetime (bad).
+        let mut t: ~Task = Local::take();
+        let ret = t.local_io().map(|t| {
+            unsafe { cast::transmute_copy(&t) }
+        });
+        Local::put(t);
+        return ret;
+    }
 
-        unsafe {
-            // First, attempt to use the local scheduler's I/O services
-            let sched: Option<*mut Scheduler> = Local::try_unsafe_borrow();
-            match sched {
-                Some(sched) => {
-                    match (*sched).event_loop.io() {
-                        Some(factory) => {
-                            return LocalIo {
-                                factory: factory,
-                            }
-                        }
-                        None => {}
+    pub fn maybe_raise<T>(f: |io: &mut IoFactory| -> Result<T, IoError>)
+        -> Option<T>
+    {
+        match LocalIo::borrow() {
+            None => {
+                io::io_error::cond.raise(io::standard_error(io::IoUnavailable));
+                None
+            }
+            Some(mut io) => {
+                match f(io.get()) {
+                    Ok(t) => Some(t),
+                    Err(ioerr) => {
+                        io::io_error::cond.raise(ioerr);
+                        None
                     }
                 }
-                None => {}
-            }
-            // If we don't have a scheduler or the scheduler doesn't have I/O
-            // services, then fall back to the native I/O services.
-            let native_io: &'static mut native::IoFactory =
-                &mut NATIVE_IO_FACTORY;
-            LocalIo {
-                factory: native_io as &mut IoFactory:'static
             }
         }
     }
 
+    pub fn new<'a>(io: &'a mut IoFactory) -> LocalIo<'a> {
+        LocalIo { factory: io }
+    }
+
     /// Returns the underlying I/O factory as a trait reference.
     #[inline]
     pub fn get<'a>(&'a mut self) -> &'a mut IoFactory {
diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs
index 30e05e9091f..e6ab159a769 100644
--- a/src/libstd/rt/task.rs
+++ b/src/libstd/rt/task.rs
@@ -13,29 +13,41 @@
 //! local storage, and logging. Even a 'freestanding' Rust would likely want
 //! to implement this.
 
-use super::local_heap::LocalHeap;
-
-use prelude::*;
-
+use any::AnyOwnExt;
 use borrow;
+use cast;
 use cleanup;
 use io::Writer;
-use libc::{c_char, size_t};
+use iter::{Iterator, Take};
 use local_data;
+use ops::Drop;
 use option::{Option, Some, None};
+use prelude::drop;
+use result::{Result, Ok, Err};
+use rt::Runtime;
 use rt::borrowck::BorrowRecord;
 use rt::borrowck;
-use rt::context::Context;
-use rt::env;
-use rt::kill::Death;
 use rt::local::Local;
+use rt::local_heap::LocalHeap;
 use rt::logging::StdErrLogger;
-use rt::sched::{Scheduler, SchedHandle};
-use rt::stack::{StackSegment, StackPool};
+use rt::rtio::LocalIo;
 use rt::unwind::Unwinder;
 use send_str::SendStr;
+use sync::arc::UnsafeArc;
+use sync::atomics::{AtomicUint, SeqCst, INIT_ATOMIC_UINT};
+use task::{TaskResult, TaskOpts};
 use unstable::finally::Finally;
-use unstable::mutex::Mutex;
+use unstable::mutex::{Mutex, MUTEX_INIT};
+
+#[cfg(stage0)]
+pub use rt::unwind::begin_unwind;
+
+// These two statics are used as bookeeping to keep track of the rust runtime's
+// count of threads. In 1:1 contexts, this is used to know when to return from
+// the main function, and in M:N contexts this is used to know when to shut down
+// the pool of schedulers.
+static mut TASK_COUNT: AtomicUint = INIT_ATOMIC_UINT;
+static mut TASK_LOCK: Mutex = MUTEX_INIT;
 
 // The Task struct represents all state associated with a rust
 // task. There are at this point two primary "subtypes" of task,
@@ -45,201 +57,90 @@ use unstable::mutex::Mutex;
 
 pub struct Task {
     heap: LocalHeap,
-    priv gc: GarbageCollector,
+    gc: GarbageCollector,
     storage: LocalStorage,
-    logger: Option<StdErrLogger>,
     unwinder: Unwinder,
     death: Death,
     destroyed: bool,
     name: Option<SendStr>,
-    coroutine: Option<Coroutine>,
-    sched: Option<~Scheduler>,
-    task_type: TaskType,
     // Dynamic borrowck debugging info
     borrow_list: Option<~[BorrowRecord]>,
+
+    logger: Option<StdErrLogger>,
     stdout_handle: Option<~Writer>,
 
-    // See the comments in the scheduler about why this is necessary
-    nasty_deschedule_lock: Mutex,
-}
-
-pub enum TaskType {
-    GreenTask(Option<SchedHome>),
-    SchedTask
-}
-
-/// A coroutine is nothing more than a (register context, stack) pair.
-pub struct Coroutine {
-    /// The segment of stack on which the task is currently running or
-    /// if the task is blocked, on which the task will resume
-    /// execution.
-    ///
-    /// Servo needs this to be public in order to tell SpiderMonkey
-    /// about the stack bounds.
-    current_stack_segment: StackSegment,
-    /// Always valid if the task is alive and not running.
-    saved_context: Context
-}
-
-/// Some tasks have a dedicated home scheduler that they must run on.
-pub enum SchedHome {
-    AnySched,
-    Sched(SchedHandle)
+    priv imp: Option<~Runtime>,
 }
 
 pub struct GarbageCollector;
 pub struct LocalStorage(Option<local_data::Map>);
 
+/// A handle to a blocked task. Usually this means having the ~Task pointer by
+/// ownership, but if the task is killable, a killer can steal it at any time.
+pub enum BlockedTask {
+    Owned(~Task),
+    Shared(UnsafeArc<AtomicUint>),
+}
+
+/// Per-task state related to task death, killing, failure, etc.
+pub struct Death {
+    // Action to be done with the exit code. If set, also makes the task wait
+    // until all its watched children exit before collecting the status.
+    on_exit: Option<proc(TaskResult)>,
+}
+
+pub struct BlockedTaskIterator {
+    priv inner: UnsafeArc<AtomicUint>,
+}
+
 impl Task {
-
-    // A helper to build a new task using the dynamically found
-    // scheduler and task. Only works in GreenTask context.
-    pub fn build_homed_child(stack_size: Option<uint>,
-                             f: proc(),
-                             home: SchedHome)
-                             -> ~Task {
-        let mut running_task = Local::borrow(None::<Task>);
-        let mut sched = running_task.get().sched.take_unwrap();
-        let new_task = ~running_task.get()
-                                    .new_child_homed(&mut sched.stack_pool,
-                                                     stack_size,
-                                                     home,
-                                                     f);
-        running_task.get().sched = Some(sched);
-        new_task
-    }
-
-    pub fn build_child(stack_size: Option<uint>, f: proc()) -> ~Task {
-        Task::build_homed_child(stack_size, f, AnySched)
-    }
-
-    pub fn build_homed_root(stack_size: Option<uint>,
-                            f: proc(),
-                            home: SchedHome)
-                            -> ~Task {
-        let mut running_task = Local::borrow(None::<Task>);
-        let mut sched = running_task.get().sched.take_unwrap();
-        let new_task = ~Task::new_root_homed(&mut sched.stack_pool,
-                                             stack_size,
-                                             home,
-                                             f);
-        running_task.get().sched = Some(sched);
-        new_task
-    }
-
-    pub fn build_root(stack_size: Option<uint>, f: proc()) -> ~Task {
-        Task::build_homed_root(stack_size, f, AnySched)
-    }
-
-    pub fn new_sched_task() -> Task {
+    pub fn new() -> Task {
         Task {
             heap: LocalHeap::new(),
             gc: GarbageCollector,
             storage: LocalStorage(None),
-            logger: None,
-            unwinder: Unwinder { unwinding: false, cause: None },
-            death: Death::new(),
-            destroyed: false,
-            coroutine: Some(Coroutine::empty()),
-            name: None,
-            sched: None,
-            task_type: SchedTask,
-            borrow_list: None,
-            stdout_handle: None,
-            nasty_deschedule_lock: unsafe { Mutex::new() },
-        }
-    }
-
-    pub fn new_root(stack_pool: &mut StackPool,
-                    stack_size: Option<uint>,
-                    start: proc()) -> Task {
-        Task::new_root_homed(stack_pool, stack_size, AnySched, start)
-    }
-
-    pub fn new_child(&mut self,
-                     stack_pool: &mut StackPool,
-                     stack_size: Option<uint>,
-                     start: proc()) -> Task {
-        self.new_child_homed(stack_pool, stack_size, AnySched, start)
-    }
-
-    pub fn new_root_homed(stack_pool: &mut StackPool,
-                          stack_size: Option<uint>,
-                          home: SchedHome,
-                          start: proc()) -> Task {
-        Task {
-            heap: LocalHeap::new(),
-            gc: GarbageCollector,
-            storage: LocalStorage(None),
-            logger: None,
-            unwinder: Unwinder { unwinding: false, cause: None },
+            unwinder: Unwinder::new(),
             death: Death::new(),
             destroyed: false,
             name: None,
-            coroutine: Some(Coroutine::new(stack_pool, stack_size, start)),
-            sched: None,
-            task_type: GreenTask(Some(home)),
             borrow_list: None,
-            stdout_handle: None,
-            nasty_deschedule_lock: unsafe { Mutex::new() },
-        }
-    }
-
-    pub fn new_child_homed(&mut self,
-                           stack_pool: &mut StackPool,
-                           stack_size: Option<uint>,
-                           home: SchedHome,
-                           start: proc()) -> Task {
-        Task {
-            heap: LocalHeap::new(),
-            gc: GarbageCollector,
-            storage: LocalStorage(None),
             logger: None,
-            unwinder: Unwinder { unwinding: false, cause: None },
-            death: Death::new(),
-            destroyed: false,
-            name: None,
-            coroutine: Some(Coroutine::new(stack_pool, stack_size, start)),
-            sched: None,
-            task_type: GreenTask(Some(home)),
-            borrow_list: None,
             stdout_handle: None,
-            nasty_deschedule_lock: unsafe { Mutex::new() },
+            imp: None,
         }
     }
 
-    pub fn give_home(&mut self, new_home: SchedHome) {
-        match self.task_type {
-            GreenTask(ref mut home) => {
-                *home = Some(new_home);
-            }
-            SchedTask => {
-                rtabort!("type error: used SchedTask as GreenTask");
-            }
-        }
-    }
-
-    pub fn take_unwrap_home(&mut self) -> SchedHome {
-        match self.task_type {
-            GreenTask(ref mut home) => {
-                let out = home.take_unwrap();
-                return out;
-            }
-            SchedTask => {
-                rtabort!("type error: used SchedTask as GreenTask");
-            }
-        }
-    }
-
-    pub fn run(&mut self, f: ||) {
-        rtdebug!("run called on task: {}", borrow::to_uint(self));
+    /// Executes the given closure as if it's running inside this task. The task
+    /// is consumed upon entry, and the destroyed task is returned from this
+    /// function in order for the caller to free. This function is guaranteed to
+    /// not unwind because the closure specified is run inside of a `rust_try`
+    /// block. (this is the only try/catch block in the world).
+    ///
+    /// This function is *not* meant to be abused as a "try/catch" block. This
+    /// is meant to be used at the absolute boundaries of a task's lifetime, and
+    /// only for that purpose.
+    pub fn run(~self, f: ||) -> ~Task {
+        // Need to put ourselves into TLS, but also need access to the unwinder.
+        // Unsafely get a handle to the task so we can continue to use it after
+        // putting it in tls (so we can invoke the unwinder).
+        let handle: *mut Task = unsafe {
+            *cast::transmute::<&~Task, &*mut Task>(&self)
+        };
+        Local::put(self);
+        unsafe { TASK_COUNT.fetch_add(1, SeqCst); }
 
         // The only try/catch block in the world. Attempt to run the task's
         // client-specified code and catch any failures.
-        self.unwinder.try(|| {
+        let try_block = || {
 
             // Run the task main function, then do some cleanup.
             f.finally(|| {
+                fn flush(w: Option<~Writer>) {
+                    match w {
+                        Some(mut w) => { w.flush(); }
+                        None => {}
+                    }
+                }
 
                 // First, destroy task-local storage. This may run user dtors.
                 //
@@ -260,7 +161,10 @@ impl Task {
                 // TLS, or possibly some destructors for those objects being
                 // annihilated invoke TLS. Sadly these two operations seemed to
                 // be intertwined, and miraculously work for now...
-                self.storage.take();
+                let mut task = Local::borrow(None::<Task>);
+                let storage = task.get().storage.take();
+                drop(task);
+                drop(storage);
 
                 // Destroy remaining boxes. Also may run user dtors.
                 unsafe { cleanup::annihilate(); }
@@ -268,77 +172,141 @@ impl Task {
                 // Finally flush and destroy any output handles which the task
                 // owns. There are no boxes here, and no user destructors should
                 // run after this any more.
-                match self.stdout_handle.take() {
-                    Some(handle) => {
-                        let mut handle = handle;
-                        handle.flush();
-                    }
-                    None => {}
-                }
-                self.logger.take();
+                let mut task = Local::borrow(None::<Task>);
+                let stdout = task.get().stdout_handle.take();
+                let logger = task.get().logger.take();
+                drop(task);
+
+                flush(stdout);
+                drop(logger);
             })
-        });
+        };
+
+        unsafe { (*handle).unwinder.try(try_block); }
 
         // Cleanup the dynamic borrowck debugging info
         borrowck::clear_task_borrow_list();
 
-        self.death.collect_failure(self.unwinder.result());
-        self.destroyed = true;
+        // Here we must unsafely borrow the task in order to not remove it from
+        // TLS. When collecting failure, we may attempt to send on a channel (or
+        // just run aribitrary code), so we must be sure to still have a local
+        // task in TLS.
+        unsafe {
+            let me: *mut Task = Local::unsafe_borrow();
+            (*me).death.collect_failure((*me).unwinder.result());
+
+            // see comments on these statics for why they're used
+            if TASK_COUNT.fetch_sub(1, SeqCst) == 1 {
+                TASK_LOCK.lock();
+                TASK_LOCK.signal();
+                TASK_LOCK.unlock();
+            }
+        }
+        let mut me: ~Task = Local::take();
+        me.destroyed = true;
+        return me;
     }
 
-    // New utility functions for homes.
+    /// Inserts a runtime object into this task, transferring ownership to the
+    /// task. It is illegal to replace a previous runtime object in this task
+    /// with this argument.
+    pub fn put_runtime(&mut self, ops: ~Runtime) {
+        assert!(self.imp.is_none());
+        self.imp = Some(ops);
+    }
 
-    pub fn is_home_no_tls(&self, sched: &~Scheduler) -> bool {
-        match self.task_type {
-            GreenTask(Some(AnySched)) => { false }
-            GreenTask(Some(Sched(SchedHandle { sched_id: ref id, .. }))) => {
-                *id == sched.sched_id()
-            }
-            GreenTask(None) => {
-                rtabort!("task without home");
-            }
-            SchedTask => {
-                // Awe yea
-                rtabort!("type error: expected: GreenTask, found: SchedTask");
+    /// Attempts to extract the runtime as a specific type. If the runtime does
+    /// not have the provided type, then the runtime is not removed. If the
+    /// runtime does have the specified type, then it is removed and returned
+    /// (transfer of ownership).
+    ///
+    /// It is recommended to only use this method when *absolutely necessary*.
+    /// This function may not be available in the future.
+    pub fn maybe_take_runtime<T: 'static>(&mut self) -> Option<~T> {
+        // This is a terrible, terrible function. The general idea here is to
+        // take the runtime, cast it to ~Any, check if it has the right type,
+        // and then re-cast it back if necessary. The method of doing this is
+        // pretty sketchy and involves shuffling vtables of trait objects
+        // around, but it gets the job done.
+        //
+        // XXX: This function is a serious code smell and should be avoided at
+        //      all costs. I have yet to think of a method to avoid this
+        //      function, and I would be saddened if more usage of the function
+        //      crops up.
+        unsafe {
+            let imp = self.imp.take_unwrap();
+            let &(vtable, _): &(uint, uint) = cast::transmute(&imp);
+            match imp.wrap().move::<T>() {
+                Ok(t) => Some(t),
+                Err(t) => {
+                    let (_, obj): (uint, uint) = cast::transmute(t);
+                    let obj: ~Runtime = cast::transmute((vtable, obj));
+                    self.put_runtime(obj);
+                    None
+                }
             }
         }
     }
 
-    pub fn homed(&self) -> bool {
-        match self.task_type {
-            GreenTask(Some(AnySched)) => { false }
-            GreenTask(Some(Sched(SchedHandle { .. }))) => { true }
-            GreenTask(None) => {
-                rtabort!("task without home");
-            }
-            SchedTask => {
-                rtabort!("type error: expected: GreenTask, found: SchedTask");
-            }
-        }
+    /// Spawns a sibling to this task. The newly spawned task is configured with
+    /// the `opts` structure and will run `f` as the body of its code.
+    pub fn spawn_sibling(mut ~self, opts: TaskOpts, f: proc()) {
+        let ops = self.imp.take_unwrap();
+        ops.spawn_sibling(self, opts, f)
     }
 
-    // Grab both the scheduler and the task from TLS and check if the
-    // task is executing on an appropriate scheduler.
-    pub fn on_appropriate_sched() -> bool {
-        let mut task = Local::borrow(None::<Task>);
-        let sched_id = task.get().sched.get_ref().sched_id();
-        let sched_run_anything = task.get().sched.get_ref().run_anything;
-        match task.get().task_type {
-            GreenTask(Some(AnySched)) => {
-                rtdebug!("anysched task in sched check ****");
-                sched_run_anything
-            }
-            GreenTask(Some(Sched(SchedHandle { sched_id: ref id, ..}))) => {
-                rtdebug!("homed task in sched check ****");
-                *id == sched_id
-            }
-            GreenTask(None) => {
-                rtabort!("task without home");
-            }
-            SchedTask => {
-                rtabort!("type error: expected: GreenTask, found: SchedTask");
-            }
+    /// Deschedules the current task, invoking `f` `amt` times. It is not
+    /// recommended to use this function directly, but rather communication
+    /// primitives in `std::comm` should be used.
+    pub fn deschedule(mut ~self, amt: uint,
+                      f: |BlockedTask| -> Result<(), BlockedTask>) {
+        let ops = self.imp.take_unwrap();
+        ops.deschedule(amt, self, f)
+    }
+
+    /// Wakes up a previously blocked task, optionally specifiying whether the
+    /// current task can accept a change in scheduling. This function can only
+    /// be called on tasks that were previously blocked in `deschedule`.
+    pub fn reawaken(mut ~self, can_resched: bool) {
+        let ops = self.imp.take_unwrap();
+        ops.reawaken(self, can_resched);
+    }
+
+    /// Yields control of this task to another task. This function will
+    /// eventually return, but possibly not immediately. This is used as an
+    /// opportunity to allow other tasks a chance to run.
+    pub fn yield_now(mut ~self) {
+        let ops = self.imp.take_unwrap();
+        ops.yield_now(self);
+    }
+
+    /// Similar to `yield_now`, except that this function may immediately return
+    /// without yielding (depending on what the runtime decides to do).
+    pub fn maybe_yield(mut ~self) {
+        let ops = self.imp.take_unwrap();
+        ops.maybe_yield(self);
+    }
+
+    /// Acquires a handle to the I/O factory that this task contains, normally
+    /// stored in the task's runtime. This factory may not always be available,
+    /// which is why the return type is `Option`
+    pub fn local_io<'a>(&'a mut self) -> Option<LocalIo<'a>> {
+        self.imp.get_mut_ref().local_io()
+    }
+
+    /// The main function of all rust executables will by default use this
+    /// function. This function will *block* the OS thread (hence the `unsafe`)
+    /// waiting for all known tasks to complete. Once this function has
+    /// returned, it is guaranteed that no more user-defined code is still
+    /// running.
+    pub unsafe fn wait_for_other_tasks(&mut self) {
+        TASK_COUNT.fetch_sub(1, SeqCst); // don't count ourselves
+        TASK_LOCK.lock();
+        while TASK_COUNT.load(SeqCst) > 0 {
+            TASK_LOCK.wait();
         }
+        TASK_LOCK.unlock();
+        TASK_COUNT.fetch_add(1, SeqCst); // add ourselves back in
     }
 }
 
@@ -346,348 +314,192 @@ impl Drop for Task {
     fn drop(&mut self) {
         rtdebug!("called drop for a task: {}", borrow::to_uint(self));
         rtassert!(self.destroyed);
-
-        unsafe { self.nasty_deschedule_lock.destroy(); }
     }
 }
 
-// Coroutines represent nothing more than a context and a stack
-// segment.
-
-impl Coroutine {
-
-    pub fn new(stack_pool: &mut StackPool,
-               stack_size: Option<uint>,
-               start: proc())
-               -> Coroutine {
-        let stack_size = match stack_size {
-            Some(size) => size,
-            None => env::min_stack()
-        };
-        let start = Coroutine::build_start_wrapper(start);
-        let mut stack = stack_pool.take_segment(stack_size);
-        let initial_context = Context::new(start, &mut stack);
-        Coroutine {
-            current_stack_segment: stack,
-            saved_context: initial_context
-        }
+impl Iterator<BlockedTask> for BlockedTaskIterator {
+    fn next(&mut self) -> Option<BlockedTask> {
+        Some(Shared(self.inner.clone()))
     }
+}
 
-    pub fn empty() -> Coroutine {
-        Coroutine {
-            current_stack_segment: StackSegment::new(0),
-            saved_context: Context::empty()
-        }
-    }
-
-    fn build_start_wrapper(start: proc()) -> proc() {
-        let wrapper: proc() = proc() {
-            // First code after swap to this new context. Run our
-            // cleanup job.
-            unsafe {
-
-                // Again - might work while safe, or it might not.
-                {
-                    let mut sched = Local::borrow(None::<Scheduler>);
-                    sched.get().run_cleanup_job();
-                }
-
-                // To call the run method on a task we need a direct
-                // reference to it. The task is in TLS, so we can
-                // simply unsafe_borrow it to get this reference. We
-                // need to still have the task in TLS though, so we
-                // need to unsafe_borrow.
-                let task: *mut Task = Local::unsafe_borrow();
-
-                let mut start_cell = Some(start);
-                (*task).run(|| {
-                    // N.B. Removing `start` from the start wrapper
-                    // closure by emptying a cell is critical for
-                    // correctness. The ~Task pointer, and in turn the
-                    // closure used to initialize the first call
-                    // frame, is destroyed in the scheduler context,
-                    // not task context. So any captured closures must
-                    // not contain user-definable dtors that expect to
-                    // be in task context. By moving `start` out of
-                    // the closure, all the user code goes our of
-                    // scope while the task is still running.
-                    let start = start_cell.take_unwrap();
-                    start();
-                });
-            }
-
-            // We remove the sched from the Task in TLS right now.
-            let sched: ~Scheduler = Local::take();
-            // ... allowing us to give it away when performing a
-            // scheduling operation.
-            sched.terminate_current_task()
-        };
-        return wrapper;
-    }
-
-    /// Destroy coroutine and try to reuse stack segment.
-    pub fn recycle(self, stack_pool: &mut StackPool) {
+impl BlockedTask {
+    /// Returns Some if the task was successfully woken; None if already killed.
+    pub fn wake(self) -> Option<~Task> {
         match self {
-            Coroutine { current_stack_segment, .. } => {
-                stack_pool.give_segment(current_stack_segment);
-            }
-        }
-    }
-
-}
-
-/// This function is invoked from rust's current __morestack function. Segmented
-/// stacks are currently not enabled as segmented stacks, but rather one giant
-/// stack segment. This means that whenever we run out of stack, we want to
-/// truly consider it to be stack overflow rather than allocating a new stack.
-#[no_mangle]      // - this is called from C code
-#[no_split_stack] // - it would be sad for this function to trigger __morestack
-#[doc(hidden)]    // - Function must be `pub` to get exported, but it's
-                  //   irrelevant for documentation purposes.
-#[cfg(not(test))] // in testing, use the original libstd's version
-pub extern "C" fn rust_stack_exhausted() {
-    use rt::context;
-    use rt::in_green_task_context;
-    use rt::task::Task;
-    use rt::local::Local;
-    use unstable::intrinsics;
-
-    unsafe {
-        // We're calling this function because the stack just ran out. We need
-        // to call some other rust functions, but if we invoke the functions
-        // right now it'll just trigger this handler being called again. In
-        // order to alleviate this, we move the stack limit to be inside of the
-        // red zone that was allocated for exactly this reason.
-        let limit = context::get_sp_limit();
-        context::record_sp_limit(limit - context::RED_ZONE / 2);
-
-        // This probably isn't the best course of action. Ideally one would want
-        // to unwind the stack here instead of just aborting the entire process.
-        // This is a tricky problem, however. There's a few things which need to
-        // be considered:
-        //
-        //  1. We're here because of a stack overflow, yet unwinding will run
-        //     destructors and hence arbitrary code. What if that code overflows
-        //     the stack? One possibility is to use the above allocation of an
-        //     extra 10k to hope that we don't hit the limit, and if we do then
-        //     abort the whole program. Not the best, but kind of hard to deal
-        //     with unless we want to switch stacks.
-        //
-        //  2. LLVM will optimize functions based on whether they can unwind or
-        //     not. It will flag functions with 'nounwind' if it believes that
-        //     the function cannot trigger unwinding, but if we do unwind on
-        //     stack overflow then it means that we could unwind in any function
-        //     anywhere. We would have to make sure that LLVM only places the
-        //     nounwind flag on functions which don't call any other functions.
-        //
-        //  3. The function that overflowed may have owned arguments. These
-        //     arguments need to have their destructors run, but we haven't even
-        //     begun executing the function yet, so unwinding will not run the
-        //     any landing pads for these functions. If this is ignored, then
-        //     the arguments will just be leaked.
-        //
-        // Exactly what to do here is a very delicate topic, and is possibly
-        // still up in the air for what exactly to do. Some relevant issues:
-        //
-        //  #3555 - out-of-stack failure leaks arguments
-        //  #3695 - should there be a stack limit?
-        //  #9855 - possible strategies which could be taken
-        //  #9854 - unwinding on windows through __morestack has never worked
-        //  #2361 - possible implementation of not using landing pads
-
-        if in_green_task_context() {
-            let mut task = Local::borrow(None::<Task>);
-            let n = task.get()
-                        .name
-                        .as_ref()
-                        .map(|n| n.as_slice())
-                        .unwrap_or("<unnamed>");
-
-            // See the message below for why this is not emitted to the
-            // task's logger. This has the additional conundrum of the
-            // logger may not be initialized just yet, meaning that an FFI
-            // call would happen to initialized it (calling out to libuv),
-            // and the FFI call needs 2MB of stack when we just ran out.
-            rterrln!("task '{}' has overflowed its stack", n);
-        } else {
-            rterrln!("stack overflow in non-task context");
-        }
-
-        intrinsics::abort();
-    }
-}
-
-/// This is the entry point of unwinding for things like lang items and such.
-/// The arguments are normally generated by the compiler, and need to
-/// have static lifetimes.
-pub fn begin_unwind_raw(msg: *c_char, file: *c_char, line: size_t) -> ! {
-    use c_str::CString;
-    use cast::transmute;
-
-    #[inline]
-    fn static_char_ptr(p: *c_char) -> &'static str {
-        let s = unsafe { CString::new(p, false) };
-        match s.as_str() {
-            Some(s) => unsafe { transmute::<&str, &'static str>(s) },
-            None => rtabort!("message wasn't utf8?")
-        }
-    }
-
-    let msg = static_char_ptr(msg);
-    let file = static_char_ptr(file);
-
-    begin_unwind(msg, file, line as uint)
-}
-
-/// This is the entry point of unwinding for fail!() and assert!().
-pub fn begin_unwind<M: Any + Send>(msg: M, file: &'static str, line: uint) -> ! {
-    use any::AnyRefExt;
-    use rt::in_green_task_context;
-    use rt::local::Local;
-    use rt::task::Task;
-    use str::Str;
-    use unstable::intrinsics;
-
-    unsafe {
-        let task: *mut Task;
-        // Note that this should be the only allocation performed in this block.
-        // Currently this means that fail!() on OOM will invoke this code path,
-        // but then again we're not really ready for failing on OOM anyway. If
-        // we do start doing this, then we should propagate this allocation to
-        // be performed in the parent of this task instead of the task that's
-        // failing.
-        let msg = ~msg as ~Any;
-
-        {
-            //let msg: &Any = msg;
-            let msg_s = match msg.as_ref::<&'static str>() {
-                Some(s) => *s,
-                None => match msg.as_ref::<~str>() {
-                    Some(s) => s.as_slice(),
-                    None => "~Any",
+            Owned(task) => Some(task),
+            Shared(arc) => unsafe {
+                match (*arc.get()).swap(0, SeqCst) {
+                    0 => None,
+                    n => Some(cast::transmute(n)),
                 }
-            };
-
-            if !in_green_task_context() {
-                rterrln!("failed in non-task context at '{}', {}:{}",
-                         msg_s, file, line);
-                intrinsics::abort();
-            }
-
-            task = Local::unsafe_borrow();
-            let n = (*task).name.as_ref().map(|n| n.as_slice()).unwrap_or("<unnamed>");
-
-            // XXX: this should no get forcibly printed to the console, this should
-            //      either be sent to the parent task (ideally), or get printed to
-            //      the task's logger. Right now the logger is actually a uvio
-            //      instance, which uses unkillable blocks internally for various
-            //      reasons. This will cause serious trouble if the task is failing
-            //      due to mismanagment of its own kill flag, so calling our own
-            //      logger in its current state is a bit of a problem.
-
-            rterrln!("task '{}' failed at '{}', {}:{}", n, msg_s, file, line);
-
-            if (*task).unwinder.unwinding {
-                rtabort!("unwinding again");
             }
         }
+    }
 
-        (*task).unwinder.begin_unwind(msg);
+    // This assertion has two flavours because the wake involves an atomic op.
+    // In the faster version, destructors will fail dramatically instead.
+    #[cfg(not(test))] pub fn trash(self) { }
+    #[cfg(test)]      pub fn trash(self) { assert!(self.wake().is_none()); }
+
+    /// Create a blocked task, unless the task was already killed.
+    pub fn block(task: ~Task) -> BlockedTask {
+        Owned(task)
+    }
+
+    /// Converts one blocked task handle to a list of many handles to the same.
+    pub fn make_selectable(self, num_handles: uint) -> Take<BlockedTaskIterator>
+    {
+        let arc = match self {
+            Owned(task) => {
+                let flag = unsafe { AtomicUint::new(cast::transmute(task)) };
+                UnsafeArc::new(flag)
+            }
+            Shared(arc) => arc.clone(),
+        };
+        BlockedTaskIterator{ inner: arc }.take(num_handles)
+    }
+
+    /// Convert to an unsafe uint value. Useful for storing in a pipe's state
+    /// flag.
+    #[inline]
+    pub unsafe fn cast_to_uint(self) -> uint {
+        match self {
+            Owned(task) => {
+                let blocked_task_ptr: uint = cast::transmute(task);
+                rtassert!(blocked_task_ptr & 0x1 == 0);
+                blocked_task_ptr
+            }
+            Shared(arc) => {
+                let blocked_task_ptr: uint = cast::transmute(~arc);
+                rtassert!(blocked_task_ptr & 0x1 == 0);
+                blocked_task_ptr | 0x1
+            }
+        }
+    }
+
+    /// Convert from an unsafe uint value. Useful for retrieving a pipe's state
+    /// flag.
+    #[inline]
+    pub unsafe fn cast_from_uint(blocked_task_ptr: uint) -> BlockedTask {
+        if blocked_task_ptr & 0x1 == 0 {
+            Owned(cast::transmute(blocked_task_ptr))
+        } else {
+            let ptr: ~UnsafeArc<AtomicUint> =
+                cast::transmute(blocked_task_ptr & !1);
+            Shared(*ptr)
+        }
+    }
+}
+
+impl Death {
+    pub fn new() -> Death {
+        Death { on_exit: None, }
+    }
+
+    /// Collect failure exit codes from children and propagate them to a parent.
+    pub fn collect_failure(&mut self, result: TaskResult) {
+        match self.on_exit.take() {
+            Some(f) => f(result),
+            None => {}
+        }
+    }
+}
+
+impl Drop for Death {
+    fn drop(&mut self) {
+        // make this type noncopyable
     }
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
-    use rt::test::*;
     use prelude::*;
+    use task;
 
     #[test]
     fn local_heap() {
-        do run_in_newsched_task() {
-            let a = @5;
-            let b = a;
-            assert!(*a == 5);
-            assert!(*b == 5);
-        }
+        let a = @5;
+        let b = a;
+        assert!(*a == 5);
+        assert!(*b == 5);
     }
 
     #[test]
     fn tls() {
         use local_data;
-        do run_in_newsched_task() {
-            local_data_key!(key: @~str)
-            local_data::set(key, @~"data");
-            assert!(*local_data::get(key, |k| k.map(|k| *k)).unwrap() == ~"data");
-            local_data_key!(key2: @~str)
-            local_data::set(key2, @~"data");
-            assert!(*local_data::get(key2, |k| k.map(|k| *k)).unwrap() == ~"data");
-        }
+        local_data_key!(key: @~str)
+        local_data::set(key, @~"data");
+        assert!(*local_data::get(key, |k| k.map(|k| *k)).unwrap() == ~"data");
+        local_data_key!(key2: @~str)
+        local_data::set(key2, @~"data");
+        assert!(*local_data::get(key2, |k| k.map(|k| *k)).unwrap() == ~"data");
     }
 
     #[test]
     fn unwind() {
-        do run_in_newsched_task() {
-            let result = spawntask_try(proc()());
-            rtdebug!("trying first assert");
-            assert!(result.is_ok());
-            let result = spawntask_try(proc() fail!());
-            rtdebug!("trying second assert");
-            assert!(result.is_err());
-        }
+        let result = task::try(proc()());
+        rtdebug!("trying first assert");
+        assert!(result.is_ok());
+        let result = task::try::<()>(proc() fail!());
+        rtdebug!("trying second assert");
+        assert!(result.is_err());
     }
 
     #[test]
     fn rng() {
-        do run_in_uv_task() {
-            use rand::{rng, Rng};
-            let mut r = rng();
-            let _ = r.next_u32();
-        }
+        use rand::{rng, Rng};
+        let mut r = rng();
+        let _ = r.next_u32();
     }
 
     #[test]
     fn logging() {
-        do run_in_uv_task() {
-            info!("here i am. logging in a newsched task");
-        }
+        info!("here i am. logging in a newsched task");
     }
 
     #[test]
     fn comm_stream() {
-        do run_in_newsched_task() {
-            let (port, chan) = Chan::new();
-            chan.send(10);
-            assert!(port.recv() == 10);
-        }
+        let (port, chan) = Chan::new();
+        chan.send(10);
+        assert!(port.recv() == 10);
     }
 
     #[test]
     fn comm_shared_chan() {
-        do run_in_newsched_task() {
-            let (port, chan) = SharedChan::new();
-            chan.send(10);
-            assert!(port.recv() == 10);
-        }
+        let (port, chan) = SharedChan::new();
+        chan.send(10);
+        assert!(port.recv() == 10);
     }
 
     #[test]
     fn heap_cycles() {
         use option::{Option, Some, None};
 
-        do run_in_newsched_task {
-            struct List {
-                next: Option<@mut List>,
-            }
-
-            let a = @mut List { next: None };
-            let b = @mut List { next: Some(a) };
-
-            a.next = Some(b);
+        struct List {
+            next: Option<@mut List>,
         }
+
+        let a = @mut List { next: None };
+        let b = @mut List { next: Some(a) };
+
+        a.next = Some(b);
     }
 
     #[test]
     #[should_fail]
-    fn test_begin_unwind() { begin_unwind("cause", file!(), line!()) }
+    fn test_begin_unwind() {
+        use rt::unwind::begin_unwind;
+        begin_unwind("cause", file!(), line!())
+    }
+
+    // Task blocking tests
+
+    #[test]
+    fn block_and_wake() {
+        let task = ~Task::new();
+        let mut task = BlockedTask::block(task).wake().unwrap();
+        task.destroyed = true;
+    }
 }
diff --git a/src/libstd/rt/test.rs b/src/libstd/rt/test.rs
deleted file mode 100644
index 2b48b396c99..00000000000
--- a/src/libstd/rt/test.rs
+++ /dev/null
@@ -1,440 +0,0 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use io::net::ip::{SocketAddr, Ipv4Addr, Ipv6Addr};
-
-use clone::Clone;
-use container::Container;
-use iter::{Iterator, range};
-use option::{Some, None};
-use os;
-use path::GenericPath;
-use path::Path;
-use rand::Rng;
-use rand;
-use result::{Result, Ok, Err};
-use rt::basic;
-use rt::deque::BufferPool;
-use comm::Chan;
-use rt::new_event_loop;
-use rt::sched::Scheduler;
-use rt::sleeper_list::SleeperList;
-use rt::task::Task;
-use rt::thread::Thread;
-use task::TaskResult;
-use unstable::{run_in_bare_thread};
-use vec;
-use vec::{OwnedVector, MutableVector, ImmutableVector};
-
-pub fn new_test_uv_sched() -> Scheduler {
-
-    let mut pool = BufferPool::new();
-    let (worker, stealer) = pool.deque();
-
-    let mut sched = Scheduler::new(new_event_loop(),
-                                   worker,
-                                   ~[stealer],
-                                   SleeperList::new());
-
-    // Don't wait for the Shutdown message
-    sched.no_sleep = true;
-    return sched;
-
-}
-
-pub fn new_test_sched() -> Scheduler {
-    let mut pool = BufferPool::new();
-    let (worker, stealer) = pool.deque();
-
-    let mut sched = Scheduler::new(basic::event_loop(),
-                                   worker,
-                                   ~[stealer],
-                                   SleeperList::new());
-
-    // Don't wait for the Shutdown message
-    sched.no_sleep = true;
-    return sched;
-}
-
-pub fn run_in_uv_task(f: proc()) {
-    do run_in_bare_thread {
-        run_in_uv_task_core(f);
-    }
-}
-
-pub fn run_in_newsched_task(f: proc()) {
-    do run_in_bare_thread {
-        run_in_newsched_task_core(f);
-    }
-}
-
-pub fn run_in_uv_task_core(f: proc()) {
-
-    use rt::sched::Shutdown;
-
-    let mut sched = ~new_test_uv_sched();
-    let exit_handle = sched.make_handle();
-
-    let on_exit: proc(TaskResult) = proc(exit_status: TaskResult) {
-        let mut exit_handle = exit_handle;
-        exit_handle.send(Shutdown);
-        rtassert!(exit_status.is_ok());
-    };
-    let mut task = ~Task::new_root(&mut sched.stack_pool, None, f);
-    task.death.on_exit = Some(on_exit);
-
-    sched.bootstrap(task);
-}
-
-pub fn run_in_newsched_task_core(f: proc()) {
-    use rt::sched::Shutdown;
-
-    let mut sched = ~new_test_sched();
-    let exit_handle = sched.make_handle();
-
-    let on_exit: proc(TaskResult) = proc(exit_status: TaskResult) {
-        let mut exit_handle = exit_handle;
-        exit_handle.send(Shutdown);
-        rtassert!(exit_status.is_ok());
-    };
-    let mut task = ~Task::new_root(&mut sched.stack_pool, None, f);
-    task.death.on_exit = Some(on_exit);
-
-    sched.bootstrap(task);
-}
-
-#[cfg(target_os="macos")]
-#[allow(non_camel_case_types)]
-mod darwin_fd_limit {
-    /*!
-     * darwin_fd_limit exists to work around an issue where launchctl on Mac OS X defaults the
-     * rlimit maxfiles to 256/unlimited. The default soft limit of 256 ends up being far too low
-     * for our multithreaded scheduler testing, depending on the number of cores available.
-     *
-     * This fixes issue #7772.
-     */
-
-    use libc;
-    type rlim_t = libc::uint64_t;
-    struct rlimit {
-        rlim_cur: rlim_t,
-        rlim_max: rlim_t
-    }
-    #[nolink]
-    extern {
-        // name probably doesn't need to be mut, but the C function doesn't specify const
-        fn sysctl(name: *mut libc::c_int, namelen: libc::c_uint,
-                  oldp: *mut libc::c_void, oldlenp: *mut libc::size_t,
-                  newp: *mut libc::c_void, newlen: libc::size_t) -> libc::c_int;
-        fn getrlimit(resource: libc::c_int, rlp: *mut rlimit) -> libc::c_int;
-        fn setrlimit(resource: libc::c_int, rlp: *rlimit) -> libc::c_int;
-    }
-    static CTL_KERN: libc::c_int = 1;
-    static KERN_MAXFILESPERPROC: libc::c_int = 29;
-    static RLIMIT_NOFILE: libc::c_int = 8;
-
-    pub unsafe fn raise_fd_limit() {
-        // The strategy here is to fetch the current resource limits, read the kern.maxfilesperproc
-        // sysctl value, and bump the soft resource limit for maxfiles up to the sysctl value.
-        use ptr::{to_unsafe_ptr, to_mut_unsafe_ptr, mut_null};
-        use mem::size_of_val;
-        use os::last_os_error;
-
-        // Fetch the kern.maxfilesperproc value
-        let mut mib: [libc::c_int, ..2] = [CTL_KERN, KERN_MAXFILESPERPROC];
-        let mut maxfiles: libc::c_int = 0;
-        let mut size: libc::size_t = size_of_val(&maxfiles) as libc::size_t;
-        if sysctl(to_mut_unsafe_ptr(&mut mib[0]), 2,
-                  to_mut_unsafe_ptr(&mut maxfiles) as *mut libc::c_void,
-                  to_mut_unsafe_ptr(&mut size),
-                  mut_null(), 0) != 0 {
-            let err = last_os_error();
-            error!("raise_fd_limit: error calling sysctl: {}", err);
-            return;
-        }
-
-        // Fetch the current resource limits
-        let mut rlim = rlimit{rlim_cur: 0, rlim_max: 0};
-        if getrlimit(RLIMIT_NOFILE, to_mut_unsafe_ptr(&mut rlim)) != 0 {
-            let err = last_os_error();
-            error!("raise_fd_limit: error calling getrlimit: {}", err);
-            return;
-        }
-
-        // Bump the soft limit to the smaller of kern.maxfilesperproc and the hard limit
-        rlim.rlim_cur = ::cmp::min(maxfiles as rlim_t, rlim.rlim_max);
-
-        // Set our newly-increased resource limit
-        if setrlimit(RLIMIT_NOFILE, to_unsafe_ptr(&rlim)) != 0 {
-            let err = last_os_error();
-            error!("raise_fd_limit: error calling setrlimit: {}", err);
-            return;
-        }
-    }
-}
-
-#[cfg(not(target_os="macos"))]
-mod darwin_fd_limit {
-    pub unsafe fn raise_fd_limit() {}
-}
-
-#[doc(hidden)]
-pub fn prepare_for_lots_of_tests() {
-    // Bump the fd limit on OS X. See darwin_fd_limit for an explanation.
-    unsafe { darwin_fd_limit::raise_fd_limit() }
-}
-
-/// Create more than one scheduler and run a function in a task
-/// in one of the schedulers. The schedulers will stay alive
-/// until the function `f` returns.
-pub fn run_in_mt_newsched_task(f: proc()) {
-    use os;
-    use from_str::FromStr;
-    use rt::sched::Shutdown;
-    use rt::util;
-
-    // see comment in other function (raising fd limits)
-    prepare_for_lots_of_tests();
-
-    do run_in_bare_thread {
-        let nthreads = match os::getenv("RUST_RT_TEST_THREADS") {
-            Some(nstr) => FromStr::from_str(nstr).unwrap(),
-            None => {
-                if util::limit_thread_creation_due_to_osx_and_valgrind() {
-                    1
-                } else {
-                    // Using more threads than cores in test code
-                    // to force the OS to preempt them frequently.
-                    // Assuming that this help stress test concurrent types.
-                    util::num_cpus() * 2
-                }
-            }
-        };
-
-        let sleepers = SleeperList::new();
-
-        let mut handles = ~[];
-        let mut scheds = ~[];
-
-        let mut pool = BufferPool::<~Task>::new();
-        let workers = range(0, nthreads).map(|_| pool.deque());
-        let (workers, stealers) = vec::unzip(workers);
-
-        for worker in workers.move_iter() {
-            let loop_ = new_event_loop();
-            let mut sched = ~Scheduler::new(loop_,
-                                            worker,
-                                            stealers.clone(),
-                                            sleepers.clone());
-            let handle = sched.make_handle();
-
-            handles.push(handle);
-            scheds.push(sched);
-        }
-
-        let handles = handles;  // Work around not being able to capture mut
-        let on_exit: proc(TaskResult) = proc(exit_status: TaskResult) {
-            // Tell schedulers to exit
-            let mut handles = handles;
-            for handle in handles.mut_iter() {
-                handle.send(Shutdown);
-            }
-
-            rtassert!(exit_status.is_ok());
-        };
-        let mut main_task = ~Task::new_root(&mut scheds[0].stack_pool,
-                                            None,
-                                            f);
-        main_task.death.on_exit = Some(on_exit);
-
-        let mut threads = ~[];
-
-        let main_thread = {
-            let sched = scheds.pop();
-            let main_task = main_task;
-            do Thread::start {
-                sched.bootstrap(main_task);
-            }
-        };
-        threads.push(main_thread);
-
-        while !scheds.is_empty() {
-            let mut sched = scheds.pop();
-            let bootstrap_task = ~do Task::new_root(&mut sched.stack_pool, None) || {
-                rtdebug!("bootstrapping non-primary scheduler");
-            };
-            let sched = sched;
-            let thread = do Thread::start {
-                sched.bootstrap(bootstrap_task);
-            };
-
-            threads.push(thread);
-        }
-
-        // Wait for schedulers
-        for thread in threads.move_iter() {
-            thread.join();
-        }
-    }
-
-}
-
-/// Test tasks will abort on failure instead of unwinding
-pub fn spawntask(f: proc()) {
-    Scheduler::run_task(Task::build_child(None, f));
-}
-
-/// Create a new task and run it right now. Aborts on failure
-pub fn spawntask_later(f: proc()) {
-    Scheduler::run_task_later(Task::build_child(None, f));
-}
-
-pub fn spawntask_random(f: proc()) {
-    use rand::{Rand, rng};
-
-    let mut rng = rng();
-    let run_now: bool = Rand::rand(&mut rng);
-
-    if run_now {
-        spawntask(f)
-    } else {
-        spawntask_later(f)
-    }
-}
-
-pub fn spawntask_try(f: proc()) -> Result<(),()> {
-
-    let (port, chan) = Chan::new();
-    let on_exit: proc(TaskResult) = proc(exit_status) {
-        chan.send(exit_status)
-    };
-
-    let mut new_task = Task::build_root(None, f);
-    new_task.death.on_exit = Some(on_exit);
-
-    Scheduler::run_task(new_task);
-
-    let exit_status = port.recv();
-    if exit_status.is_ok() { Ok(()) } else { Err(()) }
-
-}
-
-/// Spawn a new task in a new scheduler and return a thread handle.
-pub fn spawntask_thread(f: proc()) -> Thread<()> {
-    let thread = do Thread::start {
-        run_in_newsched_task_core(f);
-    };
-
-    return thread;
-}
-
-/// Get a ~Task for testing purposes other than actually scheduling it.
-pub fn with_test_task(blk: proc(~Task) -> ~Task) {
-    do run_in_bare_thread {
-        let mut sched = ~new_test_sched();
-        let task = blk(~Task::new_root(&mut sched.stack_pool,
-                                       None,
-                                       proc() {}));
-        cleanup_task(task);
-    }
-}
-
-/// Use to cleanup tasks created for testing but not "run".
-pub fn cleanup_task(mut task: ~Task) {
-    task.destroyed = true;
-}
-
-/// Get a port number, starting at 9600, for use in tests
-pub fn next_test_port() -> u16 {
-    use unstable::mutex::{Mutex, MUTEX_INIT};
-    static mut lock: Mutex = MUTEX_INIT;
-    static mut next_offset: u16 = 0;
-    unsafe {
-        let base = base_port();
-        lock.lock();
-        let ret = base + next_offset;
-        next_offset += 1;
-        lock.unlock();
-        return ret;
-    }
-}
-
-/// Get a temporary path which could be the location of a unix socket
-pub fn next_test_unix() -> Path {
-    if cfg!(unix) {
-        os::tmpdir().join(rand::task_rng().gen_ascii_str(20))
-    } else {
-        Path::new(r"\\.\pipe\" + rand::task_rng().gen_ascii_str(20))
-    }
-}
-
-/// Get a unique IPv4 localhost:port pair starting at 9600
-pub fn next_test_ip4() -> SocketAddr {
-    SocketAddr { ip: Ipv4Addr(127, 0, 0, 1), port: next_test_port() }
-}
-
-/// Get a unique IPv6 localhost:port pair starting at 9600
-pub fn next_test_ip6() -> SocketAddr {
-    SocketAddr { ip: Ipv6Addr(0, 0, 0, 0, 0, 0, 0, 1), port: next_test_port() }
-}
-
-/*
-XXX: Welcome to MegaHack City.
-
-The bots run multiple builds at the same time, and these builds
-all want to use ports. This function figures out which workspace
-it is running in and assigns a port range based on it.
-*/
-fn base_port() -> u16 {
-    use os;
-    use str::StrSlice;
-    use vec::ImmutableVector;
-
-    let base = 9600u16;
-    let range = 1000u16;
-
-    let bases = [
-        ("32-opt", base + range * 1),
-        ("32-noopt", base + range * 2),
-        ("64-opt", base + range * 3),
-        ("64-noopt", base + range * 4),
-        ("64-opt-vg", base + range * 5),
-        ("all-opt", base + range * 6),
-        ("snap3", base + range * 7),
-        ("dist", base + range * 8)
-    ];
-
-    // FIXME (#9639): This needs to handle non-utf8 paths
-    let path = os::getcwd();
-    let path_s = path.as_str().unwrap();
-
-    let mut final_base = base;
-
-    for &(dir, base) in bases.iter() {
-        if path_s.contains(dir) {
-            final_base = base;
-            break;
-        }
-    }
-
-    return final_base;
-}
-
-/// Get a constant that represents the number of times to repeat
-/// stress tests. Default 1.
-pub fn stress_factor() -> uint {
-    use os::getenv;
-    use from_str::from_str;
-
-    match getenv("RUST_RT_STRESS") {
-        Some(val) => from_str::<uint>(val).unwrap(),
-        None => 1
-    }
-}
diff --git a/src/libstd/rt/thread.rs b/src/libstd/rt/thread.rs
index 6128f310a2e..f4f4aaa2765 100644
--- a/src/libstd/rt/thread.rs
+++ b/src/libstd/rt/thread.rs
@@ -33,7 +33,7 @@ pub struct Thread<T> {
     priv packet: ~Option<T>,
 }
 
-static DEFAULT_STACK_SIZE: libc::size_t = 1024 * 1024;
+static DEFAULT_STACK_SIZE: uint = 1024 * 1024;
 
 // This is the starting point of rust os threads. The first thing we do
 // is make sure that we don't trigger __morestack (also why this has a
@@ -41,9 +41,9 @@ static DEFAULT_STACK_SIZE: libc::size_t = 1024 * 1024;
 // and invoke it.
 #[no_split_stack]
 extern fn thread_start(main: *libc::c_void) -> imp::rust_thread_return {
-    use rt::context;
+    use unstable::stack;
     unsafe {
-        context::record_stack_bounds(0, uint::max_value);
+        stack::record_stack_bounds(0, uint::max_value);
         let f: ~proc() = cast::transmute(main);
         (*f)();
         cast::transmute(0 as imp::rust_thread_return)
@@ -69,6 +69,12 @@ impl Thread<()> {
     /// called, when the `Thread` falls out of scope its destructor will block
     /// waiting for the OS thread.
     pub fn start<T: Send>(main: proc() -> T) -> Thread<T> {
+        Thread::start_stack(DEFAULT_STACK_SIZE, main)
+    }
+
+    /// Performs the same functionality as `start`, but specifies an explicit
+    /// stack size for the new thread.
+    pub fn start_stack<T: Send>(stack: uint, main: proc() -> T) -> Thread<T> {
 
         // We need the address of the packet to fill in to be stable so when
         // `main` fills it in it's still valid, so allocate an extra ~ box to do
@@ -78,7 +84,7 @@ impl Thread<()> {
             *cast::transmute::<&~Option<T>, **mut Option<T>>(&packet)
         };
         let main: proc() = proc() unsafe { *packet2 = Some(main()); };
-        let native = unsafe { imp::create(~main) };
+        let native = unsafe { imp::create(stack, ~main) };
 
         Thread {
             native: native,
@@ -94,8 +100,14 @@ impl Thread<()> {
     /// systems. Note that platforms may not keep the main program alive even if
     /// there are detached thread still running around.
     pub fn spawn(main: proc()) {
+        Thread::spawn_stack(DEFAULT_STACK_SIZE, main)
+    }
+
+    /// Performs the same functionality as `spawn`, but explicitly specifies a
+    /// stack size for the new thread.
+    pub fn spawn_stack(stack: uint, main: proc()) {
         unsafe {
-            let handle = imp::create(~main);
+            let handle = imp::create(stack, ~main);
             imp::detach(handle);
         }
     }
@@ -132,8 +144,6 @@ impl<T: Send> Drop for Thread<T> {
 
 #[cfg(windows)]
 mod imp {
-    use super::DEFAULT_STACK_SIZE;
-
     use cast;
     use libc;
     use libc::types::os::arch::extra::{LPSECURITY_ATTRIBUTES, SIZE_T, BOOL,
@@ -143,9 +153,9 @@ mod imp {
     pub type rust_thread = HANDLE;
     pub type rust_thread_return = DWORD;
 
-    pub unsafe fn create(p: ~proc()) -> rust_thread {
+    pub unsafe fn create(stack: uint, p: ~proc()) -> rust_thread {
         let arg: *mut libc::c_void = cast::transmute(p);
-        CreateThread(ptr::mut_null(), DEFAULT_STACK_SIZE, super::thread_start,
+        CreateThread(ptr::mut_null(), stack as libc::size_t, super::thread_start,
                      arg, 0, ptr::mut_null())
     }
 
@@ -183,17 +193,17 @@ mod imp {
     use libc::consts::os::posix01::PTHREAD_CREATE_JOINABLE;
     use libc;
     use ptr;
-    use super::DEFAULT_STACK_SIZE;
     use unstable::intrinsics;
 
     pub type rust_thread = libc::pthread_t;
     pub type rust_thread_return = *libc::c_void;
 
-    pub unsafe fn create(p: ~proc()) -> rust_thread {
+    pub unsafe fn create(stack: uint, p: ~proc()) -> rust_thread {
         let mut native: libc::pthread_t = intrinsics::uninit();
         let mut attr: libc::pthread_attr_t = intrinsics::uninit();
         assert_eq!(pthread_attr_init(&mut attr), 0);
-        assert_eq!(pthread_attr_setstacksize(&mut attr, DEFAULT_STACK_SIZE), 0);
+        assert_eq!(pthread_attr_setstacksize(&mut attr,
+                                             stack as libc::size_t), 0);
         assert_eq!(pthread_attr_setdetachstate(&mut attr,
                                                PTHREAD_CREATE_JOINABLE), 0);
 
diff --git a/src/libstd/rt/tube.rs b/src/libstd/rt/tube.rs
deleted file mode 100644
index 5e867bcdfba..00000000000
--- a/src/libstd/rt/tube.rs
+++ /dev/null
@@ -1,170 +0,0 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! A very simple unsynchronized channel type for sending buffered data from
-//! scheduler context to task context.
-//!
-//! XXX: This would be safer to use if split into two types like Port/Chan
-
-use option::*;
-use clone::Clone;
-use super::rc::RC;
-use rt::sched::Scheduler;
-use rt::kill::BlockedTask;
-use rt::local::Local;
-use vec::OwnedVector;
-use container::Container;
-
-struct TubeState<T> {
-    blocked_task: Option<BlockedTask>,
-    buf: ~[T]
-}
-
-pub struct Tube<T> {
-    priv p: RC<TubeState<T>>
-}
-
-impl<T> Tube<T> {
-    pub fn new() -> Tube<T> {
-        Tube {
-            p: RC::new(TubeState {
-                blocked_task: None,
-                buf: ~[]
-            })
-        }
-    }
-
-    pub fn send(&mut self, val: T) {
-        rtdebug!("tube send");
-        unsafe {
-            let state = self.p.unsafe_borrow_mut();
-            (*state).buf.push(val);
-
-            if (*state).blocked_task.is_some() {
-                // There's a waiting task. Wake it up
-                rtdebug!("waking blocked tube");
-                let task = (*state).blocked_task.take_unwrap();
-                let sched: ~Scheduler = Local::take();
-                sched.resume_blocked_task_immediately(task);
-            }
-        }
-    }
-
-    pub fn recv(&mut self) -> T {
-        unsafe {
-            let state = self.p.unsafe_borrow_mut();
-            if !(*state).buf.is_empty() {
-                return (*state).buf.shift();
-            } else {
-                // Block and wait for the next message
-                rtdebug!("blocking on tube recv");
-                assert!(self.p.refcount() > 1); // There better be somebody to wake us up
-                assert!((*state).blocked_task.is_none());
-                let sched: ~Scheduler = Local::take();
-                sched.deschedule_running_task_and_then(|_, task| {
-                    (*state).blocked_task = Some(task);
-                });
-                rtdebug!("waking after tube recv");
-                let buf = &mut (*state).buf;
-                assert!(!buf.is_empty());
-                return buf.shift();
-            }
-        }
-    }
-}
-
-impl<T> Clone for Tube<T> {
-    fn clone(&self) -> Tube<T> {
-        Tube { p: self.p.clone() }
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use rt::test::*;
-    use rt::rtio::EventLoop;
-    use rt::sched::Scheduler;
-    use rt::local::Local;
-    use super::*;
-    use prelude::*;
-
-    #[test]
-    fn simple_test() {
-        do run_in_newsched_task {
-            let mut tube: Tube<int> = Tube::new();
-            let mut tube_clone = Some(tube.clone());
-            let sched: ~Scheduler = Local::take();
-            sched.deschedule_running_task_and_then(|sched, task| {
-                let mut tube_clone = tube_clone.take_unwrap();
-                tube_clone.send(1);
-                sched.enqueue_blocked_task(task);
-            });
-
-            assert!(tube.recv() == 1);
-        }
-    }
-
-    #[test]
-    fn blocking_test() {
-        do run_in_newsched_task {
-            let mut tube: Tube<int> = Tube::new();
-            let mut tube_clone = Some(tube.clone());
-            let sched: ~Scheduler = Local::take();
-            sched.deschedule_running_task_and_then(|sched, task| {
-                let tube_clone = tube_clone.take_unwrap();
-                do sched.event_loop.callback {
-                    let mut tube_clone = tube_clone;
-                    // The task should be blocked on this now and
-                    // sending will wake it up.
-                    tube_clone.send(1);
-                }
-                sched.enqueue_blocked_task(task);
-            });
-
-            assert!(tube.recv() == 1);
-        }
-    }
-
-    #[test]
-    fn many_blocking_test() {
-        static MAX: int = 100;
-
-        do run_in_newsched_task {
-            let mut tube: Tube<int> = Tube::new();
-            let mut tube_clone = Some(tube.clone());
-            let sched: ~Scheduler = Local::take();
-            sched.deschedule_running_task_and_then(|sched, task| {
-                callback_send(tube_clone.take_unwrap(), 0);
-
-                fn callback_send(tube: Tube<int>, i: int) {
-                    if i == 100 {
-                        return
-                    }
-
-                    let mut sched = Local::borrow(None::<Scheduler>);
-                    do sched.get().event_loop.callback {
-                        let mut tube = tube;
-                        // The task should be blocked on this now and
-                        // sending will wake it up.
-                        tube.send(i);
-                        callback_send(tube, i + 1);
-                    }
-                }
-
-                sched.enqueue_blocked_task(task);
-            });
-
-            for i in range(0, MAX) {
-                let j = tube.recv();
-                assert!(j == i);
-            }
-        }
-    }
-}
diff --git a/src/libstd/rt/unwind.rs b/src/libstd/rt/unwind.rs
index 3f6f54a9c0e..9706dbae4c6 100644
--- a/src/libstd/rt/unwind.rs
+++ b/src/libstd/rt/unwind.rs
@@ -8,11 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 // Implementation of Rust stack unwinding
 //
-// For background on exception handling and stack unwinding please see "Exception Handling in LLVM"
-// (llvm.org/docs/ExceptionHandling.html) and documents linked from it.
+// For background on exception handling and stack unwinding please see
+// "Exception Handling in LLVM" (llvm.org/docs/ExceptionHandling.html) and
+// documents linked from it.
 // These are also good reads:
 //     http://theofilos.cs.columbia.edu/blog/2013/09/22/base_abi/
 //     http://monoinfinito.wordpress.com/series/exception-handling-in-c/
@@ -21,41 +21,55 @@
 // ~~~ A brief summary ~~~
 // Exception handling happens in two phases: a search phase and a cleanup phase.
 //
-// In both phases the unwinder walks stack frames from top to bottom using information from
-// the stack frame unwind sections of the current process's modules ("module" here refers to
-// an OS module, i.e. an executable or a dynamic library).
+// In both phases the unwinder walks stack frames from top to bottom using
+// information from the stack frame unwind sections of the current process's
+// modules ("module" here refers to an OS module, i.e. an executable or a
+// dynamic library).
 //
-// For each stack frame, it invokes the associated "personality routine", whose address is also
-// stored in the unwind info section.
+// For each stack frame, it invokes the associated "personality routine", whose
+// address is also stored in the unwind info section.
 //
-// In the search phase, the job of a personality routine is to examine exception object being
-// thrown, and to decide whether it should be caught at that stack frame.  Once the handler frame
-// has been identified, cleanup phase begins.
+// In the search phase, the job of a personality routine is to examine exception
+// object being thrown, and to decide whether it should be caught at that stack
+// frame.  Once the handler frame has been identified, cleanup phase begins.
 //
-// In the cleanup phase, personality routines invoke cleanup code associated with their
-// stack frames (i.e. destructors).  Once stack has been unwound down to the handler frame level,
-// unwinding stops and the last personality routine transfers control to its' catch block.
+// In the cleanup phase, personality routines invoke cleanup code associated
+// with their stack frames (i.e. destructors).  Once stack has been unwound down
+// to the handler frame level, unwinding stops and the last personality routine
+// transfers control to its' catch block.
 //
 // ~~~ Frame unwind info registration ~~~
-// Each module has its' own frame unwind info section (usually ".eh_frame"), and unwinder needs
-// to know about all of them in order for unwinding to be able to cross module boundaries.
+// Each module has its' own frame unwind info section (usually ".eh_frame"), and
+// unwinder needs to know about all of them in order for unwinding to be able to
+// cross module boundaries.
 //
-// On some platforms, like Linux, this is achieved by dynamically enumerating currently loaded
-// modules via the dl_iterate_phdr() API and finding all .eh_frame sections.
+// On some platforms, like Linux, this is achieved by dynamically enumerating
+// currently loaded modules via the dl_iterate_phdr() API and finding all
+// .eh_frame sections.
 //
-// Others, like Windows, require modules to actively register their unwind info sections by calling
-// __register_frame_info() API at startup.
-// In the latter case it is essential that there is only one copy of the unwinder runtime
-// in the process.  This is usually achieved by linking to the dynamic version of the unwind
-// runtime.
+// Others, like Windows, require modules to actively register their unwind info
+// sections by calling __register_frame_info() API at startup.  In the latter
+// case it is essential that there is only one copy of the unwinder runtime in
+// the process.  This is usually achieved by linking to the dynamic version of
+// the unwind runtime.
 //
 // Currently Rust uses unwind runtime provided by libgcc.
 
-use prelude::*;
-use cast::transmute;
-use task::TaskResult;
+use any::{Any, AnyRefExt};
+use c_str::CString;
+use cast;
+use kinds::Send;
+use libc::{c_char, size_t};
 use libc::{c_void, c_int};
-use self::libunwind::*;
+use option::{Some, None, Option};
+use result::{Err, Ok};
+use rt::local::Local;
+use rt::task::Task;
+use str::Str;
+use task::TaskResult;
+use unstable::intrinsics;
+
+use uw = self::libunwind;
 
 mod libunwind {
     //! Unwind library interface
@@ -110,34 +124,41 @@ mod libunwind {
 }
 
 pub struct Unwinder {
-    unwinding: bool,
-    cause: Option<~Any>
+    priv unwinding: bool,
+    priv cause: Option<~Any>
 }
 
 impl Unwinder {
+    pub fn new() -> Unwinder {
+        Unwinder {
+            unwinding: false,
+            cause: None,
+        }
+    }
+
+    pub fn unwinding(&self) -> bool {
+        self.unwinding
+    }
 
     pub fn try(&mut self, f: ||) {
         use unstable::raw::Closure;
 
         unsafe {
-            let closure: Closure = transmute(f);
-            let code = transmute(closure.code);
-            let env = transmute(closure.env);
-
-            let ep = rust_try(try_fn, code, env);
+            let closure: Closure = cast::transmute(f);
+            let ep = rust_try(try_fn, closure.code as *c_void,
+                              closure.env as *c_void);
             if !ep.is_null() {
                 rtdebug!("Caught {}", (*ep).exception_class);
-                _Unwind_DeleteException(ep);
+                uw::_Unwind_DeleteException(ep);
             }
         }
 
         extern fn try_fn(code: *c_void, env: *c_void) {
             unsafe {
-                let closure: Closure = Closure {
-                    code: transmute(code),
-                    env: transmute(env),
-                };
-                let closure: || = transmute(closure);
+                let closure: || = cast::transmute(Closure {
+                    code: code as *(),
+                    env: env as *(),
+                });
                 closure();
             }
         }
@@ -145,10 +166,11 @@ impl Unwinder {
         extern {
             // Rust's try-catch
             // When f(...) returns normally, the return value is null.
-            // When f(...) throws, the return value is a pointer to the caught exception object.
+            // When f(...) throws, the return value is a pointer to the caught
+            // exception object.
             fn rust_try(f: extern "C" fn(*c_void, *c_void),
                         code: *c_void,
-                        data: *c_void) -> *_Unwind_Exception;
+                        data: *c_void) -> *uw::_Unwind_Exception;
         }
     }
 
@@ -159,21 +181,21 @@ impl Unwinder {
         self.cause = Some(cause);
 
         unsafe {
-            let exception = ~_Unwind_Exception {
+            let exception = ~uw::_Unwind_Exception {
                 exception_class: rust_exception_class(),
                 exception_cleanup: exception_cleanup,
                 private_1: 0,
                 private_2: 0
             };
-            let error = _Unwind_RaiseException(transmute(exception));
+            let error = uw::_Unwind_RaiseException(cast::transmute(exception));
             rtabort!("Could not unwind stack, error = {}", error as int)
         }
 
-        extern "C" fn exception_cleanup(_unwind_code: _Unwind_Reason_Code,
-                                        exception: *_Unwind_Exception) {
+        extern "C" fn exception_cleanup(_unwind_code: uw::_Unwind_Reason_Code,
+                                        exception: *uw::_Unwind_Exception) {
             rtdebug!("exception_cleanup()");
             unsafe {
-                let _: ~_Unwind_Exception = transmute(exception);
+                let _: ~uw::_Unwind_Exception = cast::transmute(exception);
             }
         }
     }
@@ -189,68 +211,146 @@ impl Unwinder {
 
 // Rust's exception class identifier.  This is used by personality routines to
 // determine whether the exception was thrown by their own runtime.
-fn rust_exception_class() -> _Unwind_Exception_Class {
-    let bytes = bytes!("MOZ\0RUST"); // vendor, language
-    unsafe {
-        let ptr: *_Unwind_Exception_Class = transmute(bytes.as_ptr());
-        *ptr
-    }
+fn rust_exception_class() -> uw::_Unwind_Exception_Class {
+    // M O Z \0  R U S T -- vendor, language
+    0x4d4f5a_00_52555354
 }
 
-
-// We could implement our personality routine in pure Rust, however exception info decoding
-// is tedious.  More importantly, personality routines have to handle various platform
-// quirks, which are not fun to maintain.  For this reason, we attempt to reuse personality
-// routine of the C language: __gcc_personality_v0.
+// We could implement our personality routine in pure Rust, however exception
+// info decoding is tedious.  More importantly, personality routines have to
+// handle various platform quirks, which are not fun to maintain.  For this
+// reason, we attempt to reuse personality routine of the C language:
+// __gcc_personality_v0.
 //
-// Since C does not support exception catching, __gcc_personality_v0 simply always
-// returns _URC_CONTINUE_UNWIND in search phase, and always returns _URC_INSTALL_CONTEXT
-// (i.e. "invoke cleanup code") in cleanup phase.
+// Since C does not support exception catching, __gcc_personality_v0 simply
+// always returns _URC_CONTINUE_UNWIND in search phase, and always returns
+// _URC_INSTALL_CONTEXT (i.e. "invoke cleanup code") in cleanup phase.
 //
-// This is pretty close to Rust's exception handling approach, except that Rust does have
-// a single "catch-all" handler at the bottom of each task's stack.
+// This is pretty close to Rust's exception handling approach, except that Rust
+// does have a single "catch-all" handler at the bottom of each task's stack.
 // So we have two versions:
-// - rust_eh_personality, used by all cleanup landing pads, which never catches, so
-//   the behavior of __gcc_personality_v0 is perfectly adequate there, and
-// - rust_eh_personality_catch, used only by rust_try(), which always catches.  This is
-//   achieved by overriding the return value in search phase to always say "catch!".
+// - rust_eh_personality, used by all cleanup landing pads, which never catches,
+//   so the behavior of __gcc_personality_v0 is perfectly adequate there, and
+// - rust_eh_personality_catch, used only by rust_try(), which always catches.
+//   This is achieved by overriding the return value in search phase to always
+//   say "catch!".
 
 extern "C" {
     fn __gcc_personality_v0(version: c_int,
-                            actions: _Unwind_Action,
-                            exception_class: _Unwind_Exception_Class,
-                            ue_header: *_Unwind_Exception,
-                            context: *_Unwind_Context) -> _Unwind_Reason_Code;
+                            actions: uw::_Unwind_Action,
+                            exception_class: uw::_Unwind_Exception_Class,
+                            ue_header: *uw::_Unwind_Exception,
+                            context: *uw::_Unwind_Context)
+        -> uw::_Unwind_Reason_Code;
 }
 
 #[lang="eh_personality"]
 #[no_mangle] // so we can reference it by name from middle/trans/base.rs
 #[doc(hidden)]
 #[cfg(not(test))]
-pub extern "C" fn rust_eh_personality(version: c_int,
-                                      actions: _Unwind_Action,
-                                      exception_class: _Unwind_Exception_Class,
-                                      ue_header: *_Unwind_Exception,
-                                      context: *_Unwind_Context) -> _Unwind_Reason_Code {
+pub extern "C" fn rust_eh_personality(
+    version: c_int,
+    actions: uw::_Unwind_Action,
+    exception_class: uw::_Unwind_Exception_Class,
+    ue_header: *uw::_Unwind_Exception,
+    context: *uw::_Unwind_Context
+) -> uw::_Unwind_Reason_Code
+{
     unsafe {
-        __gcc_personality_v0(version, actions, exception_class, ue_header, context)
+        __gcc_personality_v0(version, actions, exception_class, ue_header,
+                             context)
     }
 }
 
 #[no_mangle] // referenced from rust_try.ll
 #[doc(hidden)]
 #[cfg(not(test))]
-pub extern "C" fn rust_eh_personality_catch(version: c_int,
-                                            actions: _Unwind_Action,
-                                            exception_class: _Unwind_Exception_Class,
-                                            ue_header: *_Unwind_Exception,
-                                            context: *_Unwind_Context) -> _Unwind_Reason_Code {
-    if (actions as c_int & _UA_SEARCH_PHASE as c_int) != 0 { // search phase
-        _URC_HANDLER_FOUND // catch!
+pub extern "C" fn rust_eh_personality_catch(
+    version: c_int,
+    actions: uw::_Unwind_Action,
+    exception_class: uw::_Unwind_Exception_Class,
+    ue_header: *uw::_Unwind_Exception,
+    context: *uw::_Unwind_Context
+) -> uw::_Unwind_Reason_Code
+{
+    if (actions as c_int & uw::_UA_SEARCH_PHASE as c_int) != 0 { // search phase
+        uw::_URC_HANDLER_FOUND // catch!
     }
     else { // cleanup phase
         unsafe {
-             __gcc_personality_v0(version, actions, exception_class, ue_header, context)
+             __gcc_personality_v0(version, actions, exception_class, ue_header,
+                                  context)
         }
     }
 }
+
+/// This is the entry point of unwinding for things like lang items and such.
+/// The arguments are normally generated by the compiler, and need to
+/// have static lifetimes.
+pub fn begin_unwind_raw(msg: *c_char, file: *c_char, line: size_t) -> ! {
+    #[inline]
+    fn static_char_ptr(p: *c_char) -> &'static str {
+        let s = unsafe { CString::new(p, false) };
+        match s.as_str() {
+            Some(s) => unsafe { cast::transmute::<&str, &'static str>(s) },
+            None => rtabort!("message wasn't utf8?")
+        }
+    }
+
+    let msg = static_char_ptr(msg);
+    let file = static_char_ptr(file);
+
+    begin_unwind(msg, file, line as uint)
+}
+
+/// This is the entry point of unwinding for fail!() and assert!().
+pub fn begin_unwind<M: Any + Send>(msg: M, file: &'static str, line: uint) -> ! {
+    unsafe {
+        let task: *mut Task;
+        // Note that this should be the only allocation performed in this block.
+        // Currently this means that fail!() on OOM will invoke this code path,
+        // but then again we're not really ready for failing on OOM anyway. If
+        // we do start doing this, then we should propagate this allocation to
+        // be performed in the parent of this task instead of the task that's
+        // failing.
+        let msg = ~msg as ~Any;
+
+        {
+            let msg_s = match msg.as_ref::<&'static str>() {
+                Some(s) => *s,
+                None => match msg.as_ref::<~str>() {
+                    Some(s) => s.as_slice(),
+                    None => "~Any",
+                }
+            };
+
+            // It is assumed that all reasonable rust code will have a local
+            // task at all times. This means that this `try_unsafe_borrow` will
+            // succeed almost all of the time. There are border cases, however,
+            // when the runtime has *almost* set up the local task, but hasn't
+            // quite gotten there yet. In order to get some better diagnostics,
+            // we print on failure and immediately abort the whole process if
+            // there is no local task available.
+            match Local::try_unsafe_borrow() {
+                Some(t) => {
+                    task = t;
+                    let n = (*task).name.as_ref()
+                                   .map(|n| n.as_slice()).unwrap_or("<unnamed>");
+
+                    rterrln!("task '{}' failed at '{}', {}:{}", n, msg_s,
+                             file, line);
+                }
+                None => {
+                    rterrln!("failed at '{}', {}:{}", msg_s, file, line);
+                    intrinsics::abort();
+                }
+            }
+
+            if (*task).unwinder.unwinding {
+                rtabort!("unwinding again");
+            }
+        }
+
+        (*task).unwinder.begin_unwind(msg);
+    }
+}
diff --git a/src/libstd/rt/util.rs b/src/libstd/rt/util.rs
index 93721986f3c..730a38ce886 100644
--- a/src/libstd/rt/util.rs
+++ b/src/libstd/rt/util.rs
@@ -15,7 +15,6 @@ use libc;
 use option::{Some, None, Option};
 use os;
 use str::StrSlice;
-use unstable::atomics::{AtomicInt, INIT_ATOMIC_INT, SeqCst};
 use unstable::running_on_valgrind;
 
 // Indicates whether we should perform expensive sanity checks, including rtassert!
@@ -68,11 +67,21 @@ pub fn default_sched_threads() -> uint {
 }
 
 pub fn dumb_println(args: &fmt::Arguments) {
-    use io::native::file::FileDesc;
     use io;
     use libc;
-    let mut out = FileDesc::new(libc::STDERR_FILENO, false);
-    fmt::writeln(&mut out as &mut io::Writer, args);
+
+    struct Stderr;
+    impl io::Writer for Stderr {
+        fn write(&mut self, data: &[u8]) {
+            unsafe {
+                libc::write(libc::STDERR_FILENO,
+                            data.as_ptr() as *libc::c_void,
+                            data.len() as libc::size_t);
+            }
+        }
+    }
+    let mut w = Stderr;
+    fmt::writeln(&mut w as &mut io::Writer, args);
 }
 
 pub fn abort(msg: &str) -> ! {
@@ -133,13 +142,3 @@ memory and partly incapable of presentation to others.",
         unsafe { libc::abort() }
     }
 }
-
-static mut EXIT_STATUS: AtomicInt = INIT_ATOMIC_INT;
-
-pub fn set_exit_status(code: int) {
-    unsafe { EXIT_STATUS.store(code, SeqCst) }
-}
-
-pub fn get_exit_status() -> int {
-    unsafe { EXIT_STATUS.load(SeqCst) }
-}
diff --git a/src/libstd/run.rs b/src/libstd/run.rs
index d92291bbfbd..69704c855ee 100644
--- a/src/libstd/run.rs
+++ b/src/libstd/run.rs
@@ -338,8 +338,8 @@ mod tests {
     use str;
     use task::spawn;
     use unstable::running_on_valgrind;
-    use io::native::file;
-    use io::{FileNotFound, Reader, Writer, io_error};
+    use io::pipe::PipeStream;
+    use io::{Writer, Reader, io_error, FileNotFound, OtherIoError};
 
     #[test]
     #[cfg(not(target_os="android"))] // FIXME(#10380)
@@ -426,13 +426,13 @@ mod tests {
     }
 
     fn writeclose(fd: c_int, s: &str) {
-        let mut writer = file::FileDesc::new(fd, true);
+        let mut writer = PipeStream::open(fd);
         writer.write(s.as_bytes());
     }
 
     fn readclose(fd: c_int) -> ~str {
         let mut res = ~[];
-        let mut reader = file::FileDesc::new(fd, true);
+        let mut reader = PipeStream::open(fd);
         let mut buf = [0, ..1024];
         loop {
             match reader.read(buf) {
diff --git a/src/libstd/sync/arc.rs b/src/libstd/sync/arc.rs
new file mode 100644
index 00000000000..7b94a3acc2b
--- /dev/null
+++ b/src/libstd/sync/arc.rs
@@ -0,0 +1,152 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Atomically reference counted data
+//!
+//! This modules contains the implementation of an atomically reference counted
+//! pointer for the purpose of sharing data between tasks. This is obviously a
+//! very unsafe primitive to use, but it has its use cases when implementing
+//! concurrent data structures and similar tasks.
+//!
+//! Great care must be taken to ensure that data races do not arise through the
+//! usage of `UnsafeArc`, and this often requires some form of external
+//! synchronization. The only guarantee provided to you by this class is that
+//! the underlying data will remain valid (not free'd) so long as the reference
+//! count is greater than one.
+
+use cast;
+use clone::Clone;
+use kinds::Send;
+use ops::Drop;
+use ptr::RawPtr;
+use sync::atomics::{AtomicUint, SeqCst, Relaxed, Acquire};
+use vec;
+
+/// An atomically reference counted pointer.
+///
+/// Enforces no shared-memory safety.
+#[unsafe_no_drop_flag]
+pub struct UnsafeArc<T> {
+    priv data: *mut ArcData<T>,
+}
+
+struct ArcData<T> {
+    count: AtomicUint,
+    data: T,
+}
+
+unsafe fn new_inner<T: Send>(data: T, refcount: uint) -> *mut ArcData<T> {
+    let data = ~ArcData { count: AtomicUint::new(refcount), data: data };
+    cast::transmute(data)
+}
+
+impl<T: Send> UnsafeArc<T> {
+    /// Creates a new `UnsafeArc` which wraps the given data.
+    pub fn new(data: T) -> UnsafeArc<T> {
+        unsafe { UnsafeArc { data: new_inner(data, 1) } }
+    }
+
+    /// As new(), but returns an extra pre-cloned handle.
+    pub fn new2(data: T) -> (UnsafeArc<T>, UnsafeArc<T>) {
+        unsafe {
+            let ptr = new_inner(data, 2);
+            (UnsafeArc { data: ptr }, UnsafeArc { data: ptr })
+        }
+    }
+
+    /// As new(), but returns a vector of as many pre-cloned handles as
+    /// requested.
+    pub fn newN(data: T, num_handles: uint) -> ~[UnsafeArc<T>] {
+        unsafe {
+            if num_handles == 0 {
+                ~[] // need to free data here
+            } else {
+                let ptr = new_inner(data, num_handles);
+                vec::from_fn(num_handles, |_| UnsafeArc { data: ptr })
+            }
+        }
+    }
+
+    /// Gets a pointer to the inner shared data. Note that care must be taken to
+    /// ensure that the outer `UnsafeArc` does not fall out of scope while this
+    /// pointer is in use, otherwise it could possibly contain a use-after-free.
+    #[inline]
+    pub fn get(&self) -> *mut T {
+        unsafe {
+            assert!((*self.data).count.load(Relaxed) > 0);
+            return &mut (*self.data).data as *mut T;
+        }
+    }
+
+    /// Gets an immutable pointer to the inner shared data. This has the same
+    /// caveats as the `get` method.
+    #[inline]
+    pub fn get_immut(&self) -> *T {
+        unsafe {
+            assert!((*self.data).count.load(Relaxed) > 0);
+            return &(*self.data).data as *T;
+        }
+    }
+}
+
+impl<T: Send> Clone for UnsafeArc<T> {
+    fn clone(&self) -> UnsafeArc<T> {
+        unsafe {
+            // This barrier might be unnecessary, but I'm not sure...
+            let old_count = (*self.data).count.fetch_add(1, Acquire);
+            assert!(old_count >= 1);
+            return UnsafeArc { data: self.data };
+        }
+    }
+}
+
+#[unsafe_destructor]
+impl<T> Drop for UnsafeArc<T>{
+    fn drop(&mut self) {
+        unsafe {
+            // Happens when destructing an unwrapper's handle and from
+            // `#[unsafe_no_drop_flag]`
+            if self.data.is_null() {
+                return
+            }
+            // Must be acquire+release, not just release, to make sure this
+            // doesn't get reordered to after the unwrapper pointer load.
+            let old_count = (*self.data).count.fetch_sub(1, SeqCst);
+            assert!(old_count >= 1);
+            if old_count == 1 {
+                let _: ~ArcData<T> = cast::transmute(self.data);
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::*;
+    use super::UnsafeArc;
+    use mem::size_of;
+
+    #[test]
+    fn test_size() {
+        assert_eq!(size_of::<UnsafeArc<[int, ..10]>>(), size_of::<*[int, ..10]>());
+    }
+
+    #[test]
+    fn arclike_newN() {
+        // Tests that the many-refcounts-at-once constructors don't leak.
+        let _ = UnsafeArc::new2(~~"hello");
+        let x = UnsafeArc::newN(~~"hello", 0);
+        assert_eq!(x.len(), 0)
+        let x = UnsafeArc::newN(~~"hello", 1);
+        assert_eq!(x.len(), 1)
+        let x = UnsafeArc::newN(~~"hello", 10);
+        assert_eq!(x.len(), 10)
+    }
+}
diff --git a/src/libstd/unstable/atomics.rs b/src/libstd/sync/atomics.rs
similarity index 98%
rename from src/libstd/unstable/atomics.rs
rename to src/libstd/sync/atomics.rs
index 9aaccb3ebba..bc9d99c0f37 100644
--- a/src/libstd/unstable/atomics.rs
+++ b/src/libstd/sync/atomics.rs
@@ -11,13 +11,16 @@
 /*!
  * Atomic types
  *
- * Basic atomic types supporting atomic operations. Each method takes an `Ordering` which
- * represents the strength of the memory barrier for that operation. These orderings are the same
- * as C++11 atomic orderings [http://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync]
+ * Basic atomic types supporting atomic operations. Each method takes an
+ * `Ordering` which represents the strength of the memory barrier for that
+ * operation. These orderings are the same as C++11 atomic orderings
+ * [http://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync]
  *
  * All atomic types are a single word in size.
  */
 
+#[allow(missing_doc)];
+
 use unstable::intrinsics;
 use cast;
 use option::{Option,Some,None};
diff --git a/src/libstd/rt/deque.rs b/src/libstd/sync/deque.rs
similarity index 98%
rename from src/libstd/rt/deque.rs
rename to src/libstd/sync/deque.rs
index 770fc9ffa12..4d0efcd6ee1 100644
--- a/src/libstd/rt/deque.rs
+++ b/src/libstd/sync/deque.rs
@@ -50,15 +50,18 @@
 
 use cast;
 use clone::Clone;
-use iter::range;
+use iter::{range, Iterator};
 use kinds::Send;
 use libc;
 use mem;
 use ops::Drop;
 use option::{Option, Some, None};
 use ptr;
-use unstable::atomics::{AtomicInt, AtomicPtr, SeqCst};
-use unstable::sync::{UnsafeArc, Exclusive};
+use ptr::RawPtr;
+use sync::arc::UnsafeArc;
+use sync::atomics::{AtomicInt, AtomicPtr, SeqCst};
+use unstable::sync::Exclusive;
+use vec::{OwnedVector, ImmutableVector};
 
 // Once the queue is less than 1/K full, then it will be downsized. Note that
 // the deque requires that this number be less than 2.
@@ -399,8 +402,8 @@ mod tests {
     use rt::thread::Thread;
     use rand;
     use rand::Rng;
-    use unstable::atomics::{AtomicBool, INIT_ATOMIC_BOOL, SeqCst,
-                            AtomicUint, INIT_ATOMIC_UINT};
+    use sync::atomics::{AtomicBool, INIT_ATOMIC_BOOL, SeqCst,
+                        AtomicUint, INIT_ATOMIC_UINT};
     use vec;
 
     #[test]
diff --git a/src/test/run-pass/rt-run-twice.rs b/src/libstd/sync/mod.rs
similarity index 52%
rename from src/test/run-pass/rt-run-twice.rs
rename to src/libstd/sync/mod.rs
index a9a26c2fbb1..3213c538152 100644
--- a/src/test/run-pass/rt-run-twice.rs
+++ b/src/libstd/sync/mod.rs
@@ -8,19 +8,16 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// xfail-fast make-check does not like `#[start]`
+//! Useful synchronization primitives
+//!
+//! This modules contains useful safe and unsafe synchronization primitives.
+//! Most of the primitives in this module do not provide any sort of locking
+//! and/or blocking at all, but rather provide the necessary tools to build
+//! other types of concurrent primitives.
 
-use std::rt;
-
-#[start]
-fn start(argc: int, argv: **u8) -> int {
-    do rt::start(argc, argv) {
-        println("First invocation");
-    };
-
-    do rt::start(argc, argv) {
-        println("Second invocation");
-    };
-
-    0
-}
+pub mod arc;
+pub mod atomics;
+pub mod deque;
+pub mod mpmc_bounded_queue;
+pub mod mpsc_queue;
+pub mod spsc_queue;
diff --git a/src/libstd/rt/mpmc_bounded_queue.rs b/src/libstd/sync/mpmc_bounded_queue.rs
similarity index 93%
rename from src/libstd/rt/mpmc_bounded_queue.rs
rename to src/libstd/sync/mpmc_bounded_queue.rs
index 25a3ba8ab48..fe51de4e42d 100644
--- a/src/libstd/rt/mpmc_bounded_queue.rs
+++ b/src/libstd/sync/mpmc_bounded_queue.rs
@@ -25,15 +25,17 @@
  * policies, either expressed or implied, of Dmitry Vyukov.
  */
 
+#[allow(missing_doc, dead_code)];
+
 // http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue
 
-use unstable::sync::UnsafeArc;
-use unstable::atomics::{AtomicUint,Relaxed,Release,Acquire};
-use option::*;
-use vec;
 use clone::Clone;
 use kinds::Send;
 use num::{Exponential,Algebraic,Round};
+use option::{Option, Some, None};
+use sync::arc::UnsafeArc;
+use sync::atomics::{AtomicUint,Relaxed,Release,Acquire};
+use vec;
 
 struct Node<T> {
     sequence: AtomicUint,
@@ -161,8 +163,8 @@ impl<T: Send> Clone for Queue<T> {
 mod tests {
     use prelude::*;
     use option::*;
-    use task;
     use super::Queue;
+    use native;
 
     #[test]
     fn test() {
@@ -170,14 +172,17 @@ mod tests {
         let nmsgs = 1000u;
         let mut q = Queue::with_capacity(nthreads*nmsgs);
         assert_eq!(None, q.pop());
+        let (port, chan) = SharedChan::new();
 
         for _ in range(0, nthreads) {
             let q = q.clone();
-            do task::spawn_sched(task::SingleThreaded) {
+            let chan = chan.clone();
+            do native::task::spawn {
                 let mut q = q;
                 for i in range(0, nmsgs) {
                     assert!(q.push(i));
                 }
+                chan.send(());
             }
         }
 
@@ -186,7 +191,7 @@ mod tests {
             let (completion_port, completion_chan) = Chan::new();
             completion_ports.push(completion_port);
             let q = q.clone();
-            do task::spawn_sched(task::SingleThreaded) {
+            do native::task::spawn {
                 let mut q = q;
                 let mut i = 0u;
                 loop {
@@ -205,5 +210,8 @@ mod tests {
         for completion_port in completion_ports.mut_iter() {
             assert_eq!(nmsgs, completion_port.recv());
         }
+        for _ in range(0, nthreads) {
+            port.recv();
+        }
     }
 }
diff --git a/src/libstd/rt/mpsc_queue.rs b/src/libstd/sync/mpsc_queue.rs
similarity index 69%
rename from src/libstd/rt/mpsc_queue.rs
rename to src/libstd/sync/mpsc_queue.rs
index d575028af70..a249d6ed2e8 100644
--- a/src/libstd/rt/mpsc_queue.rs
+++ b/src/libstd/sync/mpsc_queue.rs
@@ -26,6 +26,14 @@
  */
 
 //! A mostly lock-free multi-producer, single consumer queue.
+//!
+//! This module contains an implementation of a concurrent MPSC queue. This
+//! queue can be used to share data between tasks, and is also used as the
+//! building block of channels in rust.
+//!
+//! Note that the current implementation of this queue has a caveat of the `pop`
+//! method, and see the method for more information about it. Due to this
+//! caveat, this queue may not be appropriate for all use-cases.
 
 // http://www.1024cores.net/home/lock-free-algorithms
 //                         /queues/non-intrusive-mpsc-node-based-queue
@@ -35,9 +43,11 @@ use clone::Clone;
 use kinds::Send;
 use ops::Drop;
 use option::{Option, None, Some};
-use unstable::atomics::{AtomicPtr, Release, Acquire, AcqRel, Relaxed};
-use unstable::sync::UnsafeArc;
+use ptr::RawPtr;
+use sync::arc::UnsafeArc;
+use sync::atomics::{AtomicPtr, Release, Acquire, AcqRel, Relaxed};
 
+/// A result of the `pop` function.
 pub enum PopResult<T> {
     /// Some data has been popped
     Data(T),
@@ -61,10 +71,14 @@ struct State<T, P> {
     packet: P,
 }
 
+/// The consumer half of this concurrent queue. This half is used to receive
+/// data from the producers.
 pub struct Consumer<T, P> {
     priv state: UnsafeArc<State<T, P>>,
 }
 
+/// The production half of the concurrent queue. This handle may be cloned in
+/// order to make handles for new producers.
 pub struct Producer<T, P> {
     priv state: UnsafeArc<State<T, P>>,
 }
@@ -75,6 +89,11 @@ impl<T: Send, P: Send> Clone for Producer<T, P> {
     }
 }
 
+/// Creates a new MPSC queue. The given argument `p` is a user-defined "packet"
+/// of information which will be shared by the consumer and the producer which
+/// can be re-acquired via the `packet` function. This is helpful when extra
+/// state is shared between the producer and consumer, but note that there is no
+/// synchronization performed of this data.
 pub fn queue<T: Send, P: Send>(p: P) -> (Consumer<T, P>, Producer<T, P>) {
     unsafe {
         let (a, b) = UnsafeArc::new2(State::new(p));
@@ -92,7 +111,7 @@ impl<T> Node<T> {
 }
 
 impl<T: Send, P: Send> State<T, P> {
-    pub unsafe fn new(p: P) -> State<T, P> {
+    unsafe fn new(p: P) -> State<T, P> {
         let stub = Node::new(None);
         State {
             head: AtomicPtr::new(stub),
@@ -122,10 +141,6 @@ impl<T: Send, P: Send> State<T, P> {
 
         if self.head.load(Acquire) == tail {Empty} else {Inconsistent}
     }
-
-    unsafe fn is_empty(&mut self) -> bool {
-        return (*self.tail).next.load(Acquire).is_null();
-    }
 }
 
 #[unsafe_destructor]
@@ -143,27 +158,42 @@ impl<T: Send, P: Send> Drop for State<T, P> {
 }
 
 impl<T: Send, P: Send> Producer<T, P> {
+    /// Pushes a new value onto this queue.
     pub fn push(&mut self, value: T) {
         unsafe { (*self.state.get()).push(value) }
     }
-    pub fn is_empty(&self) -> bool {
-        unsafe{ (*self.state.get()).is_empty() }
-    }
+    /// Gets an unsafe pointer to the user-defined packet shared by the
+    /// producers and the consumer. Note that care must be taken to ensure that
+    /// the lifetime of the queue outlives the usage of the returned pointer.
     pub unsafe fn packet(&self) -> *mut P {
         &mut (*self.state.get()).packet as *mut P
     }
 }
 
 impl<T: Send, P: Send> Consumer<T, P> {
+    /// Pops some data from this queue.
+    ///
+    /// Note that the current implementation means that this function cannot
+    /// return `Option<T>`. It is possible for this queue to be in an
+    /// inconsistent state where many pushes have suceeded and completely
+    /// finished, but pops cannot return `Some(t)`. This inconsistent state
+    /// happens when a pusher is pre-empted at an inopportune moment.
+    ///
+    /// This inconsistent state means that this queue does indeed have data, but
+    /// it does not currently have access to it at this time.
     pub fn pop(&mut self) -> PopResult<T> {
         unsafe { (*self.state.get()).pop() }
     }
+    /// Attempts to pop data from this queue, but doesn't attempt too hard. This
+    /// will canonicalize inconsistent states to a `None` value.
     pub fn casual_pop(&mut self) -> Option<T> {
         match self.pop() {
             Data(t) => Some(t),
             Empty | Inconsistent => None,
         }
     }
+    /// Gets an unsafe pointer to the underlying user-defined packet. See
+    /// `Producer.packet` for more information.
     pub unsafe fn packet(&self) -> *mut P {
         &mut (*self.state.get()).packet as *mut P
     }
@@ -173,8 +203,8 @@ impl<T: Send, P: Send> Consumer<T, P> {
 mod tests {
     use prelude::*;
 
-    use task;
     use super::{queue, Data, Empty, Inconsistent};
+    use native;
 
     #[test]
     fn test_full() {
@@ -192,14 +222,17 @@ mod tests {
             Empty => {}
             Inconsistent | Data(..) => fail!()
         }
+        let (port, chan) = SharedChan::new();
 
         for _ in range(0, nthreads) {
             let q = p.clone();
-            do task::spawn_sched(task::SingleThreaded) {
+            let chan = chan.clone();
+            do native::task::spawn {
                 let mut q = q;
                 for i in range(0, nmsgs) {
                     q.push(i);
                 }
+                chan.send(());
             }
         }
 
@@ -210,6 +243,9 @@ mod tests {
                 Data(_) => { i += 1 }
             }
         }
+        for _ in range(0, nthreads) {
+            port.recv();
+        }
     }
 }
 
diff --git a/src/libstd/rt/spsc_queue.rs b/src/libstd/sync/spsc_queue.rs
similarity index 81%
rename from src/libstd/rt/spsc_queue.rs
rename to src/libstd/sync/spsc_queue.rs
index f14533d726a..6f1b887c271 100644
--- a/src/libstd/rt/spsc_queue.rs
+++ b/src/libstd/sync/spsc_queue.rs
@@ -26,12 +26,20 @@
  */
 
 // http://www.1024cores.net/home/lock-free-algorithms/queues/unbounded-spsc-queue
+
+//! A single-producer single-consumer concurrent queue
+//!
+//! This module contains the implementation of an SPSC queue which can be used
+//! concurrently between two tasks. This data structure is safe to use and
+//! enforces the semantics that there is one pusher and one popper.
+
 use cast;
 use kinds::Send;
 use ops::Drop;
 use option::{Some, None, Option};
-use unstable::atomics::{AtomicPtr, Relaxed, AtomicUint, Acquire, Release};
-use unstable::sync::UnsafeArc;
+use ptr::RawPtr;
+use sync::arc::UnsafeArc;
+use sync::atomics::{AtomicPtr, Relaxed, AtomicUint, Acquire, Release};
 
 // Node within the linked list queue of messages to send
 struct Node<T> {
@@ -64,14 +72,34 @@ struct State<T, P> {
     packet: P,
 }
 
+/// Producer half of this queue. This handle is used to push data to the
+/// consumer.
 pub struct Producer<T, P> {
     priv state: UnsafeArc<State<T, P>>,
 }
 
+/// Consumer half of this queue. This handle is used to receive data from the
+/// producer.
 pub struct Consumer<T, P> {
     priv state: UnsafeArc<State<T, P>>,
 }
 
+/// Creates a new queue. The producer returned is connected to the consumer to
+/// push all data to the consumer.
+///
+/// # Arguments
+///
+///   * `bound` - This queue implementation is implemented with a linked list,
+///               and this means that a push is always a malloc. In order to
+///               amortize this cost, an internal cache of nodes is maintained
+///               to prevent a malloc from always being necessary. This bound is
+///               the limit on the size of the cache (if desired). If the value
+///               is 0, then the cache has no bound. Otherwise, the cache will
+///               never grow larger than `bound` (although the queue itself
+///               could be much larger.
+///
+///   * `p` - This is the user-defined packet of data which will also be shared
+///           between the producer and consumer.
 pub fn queue<T: Send, P: Send>(bound: uint,
                                p: P) -> (Consumer<T, P>, Producer<T, P>)
 {
@@ -105,21 +133,31 @@ impl<T: Send> Node<T> {
 }
 
 impl<T: Send, P: Send> Producer<T, P> {
+    /// Pushes data onto the queue
     pub fn push(&mut self, t: T) {
         unsafe { (*self.state.get()).push(t) }
     }
+    /// Tests whether the queue is empty. Note that if this function returns
+    /// `false`, the return value is significant, but if the return value is
+    /// `true` then almost no meaning can be attached to the return value.
     pub fn is_empty(&self) -> bool {
         unsafe { (*self.state.get()).is_empty() }
     }
+    /// Acquires an unsafe pointer to the underlying user-defined packet. Note
+    /// that care must be taken to ensure that the queue outlives the usage of
+    /// the packet (because it is an unsafe pointer).
     pub unsafe fn packet(&self) -> *mut P {
         &mut (*self.state.get()).packet as *mut P
     }
 }
 
 impl<T: Send, P: Send> Consumer<T, P> {
+    /// Pops some data from this queue, returning `None` when the queue is
+    /// empty.
     pub fn pop(&mut self) -> Option<T> {
         unsafe { (*self.state.get()).pop() }
     }
+    /// Same function as the producer's `packet` method.
     pub unsafe fn packet(&self) -> *mut P {
         &mut (*self.state.get()).packet as *mut P
     }
@@ -230,7 +268,7 @@ impl<T: Send, P: Send> Drop for State<T, P> {
 mod test {
     use prelude::*;
     use super::queue;
-    use task;
+    use native;
 
     #[test]
     fn smoke() {
@@ -276,7 +314,8 @@ mod test {
 
         fn stress_bound(bound: uint) {
             let (c, mut p) = queue(bound, ());
-            do task::spawn_sched(task::SingleThreaded) {
+            let (port, chan) = Chan::new();
+            do native::task::spawn {
                 let mut c = c;
                 for _ in range(0, 100000) {
                     loop {
@@ -287,10 +326,12 @@ mod test {
                         }
                     }
                 }
+                chan.send(());
             }
             for _ in range(0, 100000) {
                 p.push(1);
             }
+            port.recv();
         }
     }
 }
diff --git a/src/libstd/task/mod.rs b/src/libstd/task.rs
similarity index 74%
rename from src/libstd/task/mod.rs
rename to src/libstd/task.rs
index 3310dddc327..2f0f9bf64af 100644
--- a/src/libstd/task/mod.rs
+++ b/src/libstd/task.rs
@@ -53,22 +53,22 @@
 
 #[allow(missing_doc)];
 
-use prelude::*;
-
+use any::Any;
 use comm::{Chan, Port};
+use kinds::Send;
+use option::{None, Some, Option};
 use result::{Result, Ok, Err};
-use rt::in_green_task_context;
 use rt::local::Local;
+use rt::task::Task;
 use send_str::{SendStr, IntoSendStr};
+use str::Str;
 use util;
 
-#[cfg(test)] use any::Any;
+#[cfg(test)] use any::{AnyOwnExt, AnyRefExt};
 #[cfg(test)] use comm::SharedChan;
 #[cfg(test)] use ptr;
 #[cfg(test)] use result;
 
-pub mod spawn;
-
 /// Indicates the manner in which a task exited.
 ///
 /// A task that completes without failing is considered to exit successfully.
@@ -80,27 +80,6 @@ pub mod spawn;
 /// children tasks complete, recommend using a result future.
 pub type TaskResult = Result<(), ~Any>;
 
-/// Scheduler modes
-#[deriving(Eq)]
-pub enum SchedMode {
-    /// Run task on the default scheduler
-    DefaultScheduler,
-    /// All tasks run in the same OS thread
-    SingleThreaded,
-}
-
-/**
- * Scheduler configuration options
- *
- * # Fields
- *
- * * sched_mode - The operating mode of the scheduler
- *
- */
-pub struct SchedOpts {
-    priv mode: SchedMode,
-}
-
 /**
  * Task configuration options
  *
@@ -121,10 +100,9 @@ pub struct SchedOpts {
  *           scheduler other tasks will be impeded or even blocked indefinitely.
  */
 pub struct TaskOpts {
-    priv watched: bool,
-    priv notify_chan: Option<Chan<TaskResult>>,
+    watched: bool,
+    notify_chan: Option<Chan<TaskResult>>,
     name: Option<SendStr>,
-    sched: SchedOpts,
     stack_size: Option<uint>
 }
 
@@ -153,7 +131,7 @@ pub struct TaskBuilder {
  */
 pub fn task() -> TaskBuilder {
     TaskBuilder {
-        opts: default_task_opts(),
+        opts: TaskOpts::new(),
         gen_body: None,
         can_not_copy: None,
     }
@@ -169,7 +147,6 @@ impl TaskBuilder {
                 watched: self.opts.watched,
                 notify_chan: notify_chan,
                 name: name,
-                sched: self.opts.sched,
                 stack_size: self.opts.stack_size
             },
             gen_body: gen_body,
@@ -229,11 +206,6 @@ impl TaskBuilder {
         self.opts.name = Some(name.into_send_str());
     }
 
-    /// Configure a custom scheduler mode for the task.
-    pub fn sched_mode(&mut self, mode: SchedMode) {
-        self.opts.sched.mode = mode;
-    }
-
     /**
      * Add a wrapper to the body of the spawned task.
      *
@@ -285,7 +257,6 @@ impl TaskBuilder {
             watched: x.opts.watched,
             notify_chan: notify_chan,
             name: name,
-            sched: x.opts.sched,
             stack_size: x.opts.stack_size
         };
         let f = match gen_body {
@@ -296,7 +267,9 @@ impl TaskBuilder {
                 f
             }
         };
-        spawn::spawn_raw(opts, f);
+
+        let t: ~Task = Local::take();
+        t.spawn_sibling(opts, f);
     }
 
     /**
@@ -328,25 +301,23 @@ impl TaskBuilder {
     }
 }
 
-
 /* Task construction */
 
-pub fn default_task_opts() -> TaskOpts {
-    /*!
-     * The default task options
-     *
-     * By default all tasks are supervised by their parent, are spawned
-     * into the same scheduler, and do not post lifecycle notifications.
-     */
+impl TaskOpts {
+    pub fn new() -> TaskOpts {
+        /*!
+         * The default task options
+         *
+         * By default all tasks are supervised by their parent, are spawned
+         * into the same scheduler, and do not post lifecycle notifications.
+         */
 
-    TaskOpts {
-        watched: true,
-        notify_chan: None,
-        name: None,
-        sched: SchedOpts {
-            mode: DefaultScheduler,
-        },
-        stack_size: None
+        TaskOpts {
+            watched: true,
+            notify_chan: None,
+            name: None,
+            stack_size: None
+        }
     }
 }
 
@@ -363,24 +334,6 @@ pub fn spawn(f: proc()) {
     task.spawn(f)
 }
 
-pub fn spawn_sched(mode: SchedMode, f: proc()) {
-    /*!
-     * Creates a new task on a new or existing scheduler.
-     *
-     * When there are no more tasks to execute the
-     * scheduler terminates.
-     *
-     * # Failure
-     *
-     * In manual threads mode the number of threads requested must be
-     * greater than zero.
-     */
-
-    let mut task = task();
-    task.sched_mode(mode);
-    task.spawn(f)
-}
-
 pub fn try<T:Send>(f: proc() -> T) -> Result<T, ~Any> {
     /*!
      * Execute a function in another task and return either the return value
@@ -400,14 +353,10 @@ pub fn try<T:Send>(f: proc() -> T) -> Result<T, ~Any> {
 pub fn with_task_name<U>(blk: |Option<&str>| -> U) -> U {
     use rt::task::Task;
 
-    if in_green_task_context() {
-        let mut task = Local::borrow(None::<Task>);
-        match task.get().name {
-            Some(ref name) => blk(Some(name.as_slice())),
-            None => blk(None)
-        }
-    } else {
-        fail!("no task name exists in non-green task context")
+    let mut task = Local::borrow(None::<Task>);
+    match task.get().name {
+        Some(ref name) => blk(Some(name.as_slice())),
+        None => blk(None)
     }
 }
 
@@ -415,11 +364,10 @@ pub fn deschedule() {
     //! Yield control to the task scheduler
 
     use rt::local::Local;
-    use rt::sched::Scheduler;
 
     // FIXME(#7544): Optimize this, since we know we won't block.
-    let sched: ~Scheduler = Local::take();
-    sched.yield_now();
+    let task: ~Task = Local::take();
+    task.yield_now();
 }
 
 pub fn failing() -> bool {
@@ -428,7 +376,7 @@ pub fn failing() -> bool {
     use rt::task::Task;
 
     let mut local = Local::borrow(None::<Task>);
-    local.get().unwinder.unwinding
+    local.get().unwinder.unwinding()
 }
 
 // The following 8 tests test the following 2^3 combinations:
@@ -439,59 +387,43 @@ pub fn failing() -> bool {
 
 #[test]
 fn test_unnamed_task() {
-    use rt::test::run_in_uv_task;
-
-    do run_in_uv_task {
-        do spawn {
-            with_task_name(|name| {
-                assert!(name.is_none());
-            })
-        }
+    do spawn {
+        with_task_name(|name| {
+            assert!(name.is_none());
+        })
     }
 }
 
 #[test]
 fn test_owned_named_task() {
-    use rt::test::run_in_uv_task;
-
-    do run_in_uv_task {
-        let mut t = task();
-        t.name(~"ada lovelace");
-        do t.spawn {
-            with_task_name(|name| {
-                assert!(name.unwrap() == "ada lovelace");
-            })
-        }
+    let mut t = task();
+    t.name(~"ada lovelace");
+    do t.spawn {
+        with_task_name(|name| {
+            assert!(name.unwrap() == "ada lovelace");
+        })
     }
 }
 
 #[test]
 fn test_static_named_task() {
-    use rt::test::run_in_uv_task;
-
-    do run_in_uv_task {
-        let mut t = task();
-        t.name("ada lovelace");
-        do t.spawn {
-            with_task_name(|name| {
-                assert!(name.unwrap() == "ada lovelace");
-            })
-        }
+    let mut t = task();
+    t.name("ada lovelace");
+    do t.spawn {
+        with_task_name(|name| {
+            assert!(name.unwrap() == "ada lovelace");
+        })
     }
 }
 
 #[test]
 fn test_send_named_task() {
-    use rt::test::run_in_uv_task;
-
-    do run_in_uv_task {
-        let mut t = task();
-        t.name("ada lovelace".into_send_str());
-        do t.spawn {
-            with_task_name(|name| {
-                assert!(name.unwrap() == "ada lovelace");
-            })
-        }
+    let mut t = task();
+    t.name("ada lovelace".into_send_str());
+    do t.spawn {
+        with_task_name(|name| {
+            assert!(name.unwrap() == "ada lovelace");
+        })
     }
 }
 
@@ -562,28 +494,19 @@ fn test_try_fail() {
     }
 }
 
-#[cfg(test)]
-fn get_sched_id() -> int {
-    use rt::sched::Scheduler;
-    let mut sched = Local::borrow(None::<Scheduler>);
-    sched.get().sched_id() as int
-}
-
 #[test]
 fn test_spawn_sched() {
+    use clone::Clone;
+
     let (po, ch) = SharedChan::new();
 
     fn f(i: int, ch: SharedChan<()>) {
-        let parent_sched_id = get_sched_id();
-
-        do spawn_sched(SingleThreaded) {
-            let child_sched_id = get_sched_id();
-            assert!(parent_sched_id != child_sched_id);
-
+        let ch = ch.clone();
+        do spawn {
             if (i == 0) {
                 ch.send(());
             } else {
-                f(i - 1, ch.clone());
+                f(i - 1, ch);
             }
         };
 
@@ -596,16 +519,9 @@ fn test_spawn_sched() {
 fn test_spawn_sched_childs_on_default_sched() {
     let (po, ch) = Chan::new();
 
-    // Assuming tests run on the default scheduler
-    let default_id = get_sched_id();
-
-    do spawn_sched(SingleThreaded) {
+    do spawn {
         let ch = ch;
-        let parent_sched_id = get_sched_id();
         do spawn {
-            let child_sched_id = get_sched_id();
-            assert!(parent_sched_id != child_sched_id);
-            assert_eq!(child_sched_id, default_id);
             ch.send(());
         };
     };
@@ -613,65 +529,6 @@ fn test_spawn_sched_childs_on_default_sched() {
     po.recv();
 }
 
-#[test]
-fn test_spawn_sched_blocking() {
-    use unstable::mutex::Mutex;
-
-    unsafe {
-
-        // Testing that a task in one scheduler can block in foreign code
-        // without affecting other schedulers
-        20u.times(|| {
-            let (start_po, start_ch) = Chan::new();
-            let (fin_po, fin_ch) = Chan::new();
-
-            let mut lock = Mutex::new();
-            let lock2 = lock.clone();
-
-            do spawn_sched(SingleThreaded) {
-                let mut lock = lock2;
-                lock.lock();
-
-                start_ch.send(());
-
-                // Block the scheduler thread
-                lock.wait();
-                lock.unlock();
-
-                fin_ch.send(());
-            };
-
-            // Wait until the other task has its lock
-            start_po.recv();
-
-            fn pingpong(po: &Port<int>, ch: &Chan<int>) {
-                let mut val = 20;
-                while val > 0 {
-                    val = po.recv();
-                    ch.try_send(val - 1);
-                }
-            }
-
-            let (setup_po, setup_ch) = Chan::new();
-            let (parent_po, parent_ch) = Chan::new();
-            do spawn {
-                let (child_po, child_ch) = Chan::new();
-                setup_ch.send(child_ch);
-                pingpong(&child_po, &parent_ch);
-            };
-
-            let child_ch = setup_po.recv();
-            child_ch.send(20);
-            pingpong(&parent_po, &child_ch);
-            lock.lock();
-            lock.signal();
-            lock.unlock();
-            fin_po.recv();
-            lock.destroy();
-        })
-    }
-}
-
 #[cfg(test)]
 fn avoid_copying_the_body(spawnfn: |v: proc()|) {
     let (p, ch) = Chan::<uint>::new();
@@ -735,11 +592,7 @@ fn test_child_doesnt_ref_parent() {
 
 #[test]
 fn test_simple_newsched_spawn() {
-    use rt::test::run_in_uv_task;
-
-    do run_in_uv_task {
-        spawn(proc()())
-    }
+    spawn(proc()())
 }
 
 #[test]
diff --git a/src/libstd/task/spawn.rs b/src/libstd/task/spawn.rs
deleted file mode 100644
index 1148774020a..00000000000
--- a/src/libstd/task/spawn.rs
+++ /dev/null
@@ -1,233 +0,0 @@
-// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-/*!**************************************************************************
- *
- * WARNING: linked failure has been removed since this doc comment was written,
- *          but it was so pretty that I didn't want to remove it.
- *
- * Spawning & linked failure
- *
- * Several data structures are involved in task management to allow properly
- * propagating failure across linked/supervised tasks.
- *
- * (1) The "taskgroup_arc" is an unsafe::exclusive which contains a hashset of
- *     all tasks that are part of the group. Some tasks are 'members', which
- *     means if they fail, they will kill everybody else in the taskgroup.
- *     Other tasks are 'descendants', which means they will not kill tasks
- *     from this group, but can be killed by failing members.
- *
- *     A new one of these is created each spawn_linked or spawn_supervised.
- *
- * (2) The "taskgroup" is a per-task control structure that tracks a task's
- *     spawn configuration. It contains a reference to its taskgroup_arc, a
- *     reference to its node in the ancestor list (below), and an optionally
- *     configured notification port. These are stored in TLS.
- *
- * (3) The "ancestor_list" is a cons-style list of unsafe::exclusives which
- *     tracks 'generations' of taskgroups -- a group's ancestors are groups
- *     which (directly or transitively) spawn_supervised-ed them. Each task
- *     is recorded in the 'descendants' of each of its ancestor groups.
- *
- *     Spawning a supervised task is O(n) in the number of generations still
- *     alive, and exiting (by success or failure) that task is also O(n).
- *
- * This diagram depicts the references between these data structures:
- *
- *          linked_________________________________
- *        ___/                   _________         \___
- *       /   \                  | group X |        /   \
- *      (  A  ) - - - - - - - > | {A,B} {}|< - - -(  B  )
- *       \___/                  |_________|        \___/
- *      unlinked
- *         |      __ (nil)
- *         |      //|                         The following code causes this:
- *         |__   //   /\         _________
- *        /   \ //    ||        | group Y |     fn taskA() {
- *       (  C  )- - - ||- - - > |{C} {D,E}|         spawn(taskB);
- *        \___/      /  \=====> |_________|         spawn_unlinked(taskC);
- *      supervise   /gen \                          ...
- *         |    __  \ 00 /                      }
- *         |    //|  \__/                       fn taskB() { ... }
- *         |__ //     /\         _________      fn taskC() {
- *        /   \/      ||        | group Z |         spawn_supervised(taskD);
- *       (  D  )- - - ||- - - > | {D} {E} |         ...
- *        \___/      /  \=====> |_________|     }
- *      supervise   /gen \                      fn taskD() {
- *         |    __  \ 01 /                          spawn_supervised(taskE);
- *         |    //|  \__/                           ...
- *         |__ //                _________      }
- *        /   \/                | group W |     fn taskE() { ... }
- *       (  E  )- - - - - - - > | {E}  {} |
- *        \___/                 |_________|
- *
- *        "tcb"               "taskgroup_arc"
- *             "ancestor_list"
- *
- ****************************************************************************/
-
-#[doc(hidden)];
-
-use prelude::*;
-
-use comm::Chan;
-use rt::local::Local;
-use rt::sched::{Scheduler, Shutdown, TaskFromFriend};
-use rt::task::{Task, Sched};
-use rt::thread::Thread;
-use rt::{in_green_task_context, new_event_loop};
-use task::{SingleThreaded, TaskOpts, TaskResult};
-
-#[cfg(test)] use task::default_task_opts;
-#[cfg(test)] use task;
-
-pub fn spawn_raw(mut opts: TaskOpts, f: proc()) {
-    assert!(in_green_task_context());
-
-    let mut task = if opts.sched.mode != SingleThreaded {
-        if opts.watched {
-            Task::build_child(opts.stack_size, f)
-        } else {
-            Task::build_root(opts.stack_size, f)
-        }
-    } else {
-        unsafe {
-            // Creating a 1:1 task:thread ...
-            let sched: *mut Scheduler = Local::unsafe_borrow();
-            let sched_handle = (*sched).make_handle();
-
-            // Since this is a 1:1 scheduler we create a queue not in
-            // the stealee set. The run_anything flag is set false
-            // which will disable stealing.
-            let (worker, _stealer) = (*sched).work_queue.pool().deque();
-
-            // Create a new scheduler to hold the new task
-            let mut new_sched = ~Scheduler::new_special(new_event_loop(),
-                                                        worker,
-                                                        (*sched).work_queues.clone(),
-                                                        (*sched).sleeper_list.clone(),
-                                                        false,
-                                                        Some(sched_handle));
-            let mut new_sched_handle = new_sched.make_handle();
-
-            // Allow the scheduler to exit when the pinned task exits
-            new_sched_handle.send(Shutdown);
-
-            // Pin the new task to the new scheduler
-            let new_task = if opts.watched {
-                Task::build_homed_child(opts.stack_size, f, Sched(new_sched_handle))
-            } else {
-                Task::build_homed_root(opts.stack_size, f, Sched(new_sched_handle))
-            };
-
-            // Create a task that will later be used to join with the new scheduler
-            // thread when it is ready to terminate
-            let (thread_port, thread_chan) = Chan::new();
-            let join_task = do Task::build_child(None) {
-                debug!("running join task");
-                let thread: Thread<()> = thread_port.recv();
-                thread.join();
-            };
-
-            // Put the scheduler into another thread
-            let orig_sched_handle = (*sched).make_handle();
-
-            let new_sched = new_sched;
-            let thread = do Thread::start {
-                let mut new_sched = new_sched;
-                let mut orig_sched_handle = orig_sched_handle;
-
-                let bootstrap_task = ~do Task::new_root(&mut new_sched.stack_pool, None) || {
-                    debug!("boostrapping a 1:1 scheduler");
-                };
-                new_sched.bootstrap(bootstrap_task);
-
-                // Now tell the original scheduler to join with this thread
-                // by scheduling a thread-joining task on the original scheduler
-                orig_sched_handle.send(TaskFromFriend(join_task));
-
-                // NB: We can't simply send a message from here to another task
-                // because this code isn't running in a task and message passing doesn't
-                // work outside of tasks. Hence we're sending a scheduler message
-                // to execute a new task directly to a scheduler.
-            };
-
-            // Give the thread handle to the join task
-            thread_chan.send(thread);
-
-            // When this task is enqueued on the current scheduler it will then get
-            // forwarded to the scheduler to which it is pinned
-            new_task
-        }
-    };
-
-    if opts.notify_chan.is_some() {
-        let notify_chan = opts.notify_chan.take_unwrap();
-        let on_exit: proc(TaskResult) = proc(task_result) {
-            notify_chan.try_send(task_result);
-        };
-        task.death.on_exit = Some(on_exit);
-    }
-
-    task.name = opts.name.take();
-    debug!("spawn calling run_task");
-    Scheduler::run_task(task);
-
-}
-
-#[test]
-fn test_spawn_raw_simple() {
-    let (po, ch) = Chan::new();
-    do spawn_raw(default_task_opts()) {
-        ch.send(());
-    }
-    po.recv();
-}
-
-#[test]
-fn test_spawn_raw_unsupervise() {
-    let opts = task::TaskOpts {
-        watched: false,
-        notify_chan: None,
-        .. default_task_opts()
-    };
-    do spawn_raw(opts) {
-        fail!();
-    }
-}
-
-#[test]
-fn test_spawn_raw_notify_success() {
-    let (notify_po, notify_ch) = Chan::new();
-
-    let opts = task::TaskOpts {
-        notify_chan: Some(notify_ch),
-        .. default_task_opts()
-    };
-    do spawn_raw(opts) {
-    }
-    assert!(notify_po.recv().is_ok());
-}
-
-#[test]
-fn test_spawn_raw_notify_failure() {
-    // New bindings for these
-    let (notify_po, notify_ch) = Chan::new();
-
-    let opts = task::TaskOpts {
-        watched: false,
-        notify_chan: Some(notify_ch),
-        .. default_task_opts()
-    };
-    do spawn_raw(opts) {
-        fail!();
-    }
-    assert!(notify_po.recv().is_err());
-}
diff --git a/src/libstd/unstable/dynamic_lib.rs b/src/libstd/unstable/dynamic_lib.rs
index 03b25fbd044..0569fe32c58 100644
--- a/src/libstd/unstable/dynamic_lib.rs
+++ b/src/libstd/unstable/dynamic_lib.rs
@@ -140,7 +140,6 @@ pub mod dl {
     use path;
     use ptr;
     use str;
-    use unstable::sync::atomic;
     use result::*;
 
     pub unsafe fn open_external(filename: &path::Path) -> *libc::c_void {
@@ -158,11 +157,7 @@ pub mod dl {
         static mut lock: Mutex = MUTEX_INIT;
         unsafe {
             // dlerror isn't thread safe, so we need to lock around this entire
-            // sequence. `atomic` asserts that we don't do anything that
-            // would cause this task to be descheduled, which could deadlock
-            // the scheduler if it happens while the lock is held.
-            // FIXME #9105 use a Rust mutex instead of C++ mutexes.
-            let _guard = atomic();
+            // sequence
             lock.lock();
             let _old_error = dlerror();
 
@@ -208,7 +203,6 @@ pub mod dl {
     use libc;
     use path;
     use ptr;
-    use unstable::sync::atomic;
     use result::*;
 
     pub unsafe fn open_external(filename: &path::Path) -> *libc::c_void {
@@ -225,7 +219,6 @@ pub mod dl {
 
     pub fn check_for_errors_in<T>(f: || -> T) -> Result<T, ~str> {
         unsafe {
-            let _guard = atomic();
             SetLastError(0);
 
             let result = f();
diff --git a/src/libstd/unstable/lang.rs b/src/libstd/unstable/lang.rs
index 06f9ba65ae7..e7e8cec9d5f 100644
--- a/src/libstd/unstable/lang.rs
+++ b/src/libstd/unstable/lang.rs
@@ -11,15 +11,13 @@
 //! Runtime calls emitted by the compiler.
 
 use c_str::ToCStr;
-use cast::transmute;
 use libc::{c_char, size_t, uintptr_t};
-use rt::task;
 use rt::borrowck;
 
 #[cold]
 #[lang="fail_"]
 pub fn fail_(expr: *c_char, file: *c_char, line: size_t) -> ! {
-    task::begin_unwind_raw(expr, file, line);
+    ::rt::begin_unwind_raw(expr, file, line);
 }
 
 #[cold]
@@ -81,15 +79,3 @@ pub unsafe fn check_not_borrowed(a: *u8,
                                  line: size_t) {
     borrowck::check_not_borrowed(a, file, line)
 }
-
-#[lang="start"]
-pub fn start(main: *u8, argc: int, argv: **c_char) -> int {
-    use rt;
-
-    unsafe {
-        return do rt::start(argc, argv as **u8) {
-            let main: extern "Rust" fn() = transmute(main);
-            main();
-        };
-    }
-}
diff --git a/src/libstd/unstable/mod.rs b/src/libstd/unstable/mod.rs
index 043d99eb1b8..f4573785996 100644
--- a/src/libstd/unstable/mod.rs
+++ b/src/libstd/unstable/mod.rs
@@ -22,8 +22,8 @@ pub mod simd;
 pub mod lang;
 pub mod sync;
 pub mod mutex;
-pub mod atomics;
 pub mod raw;
+pub mod stack;
 
 /**
 
diff --git a/src/libstd/unstable/mutex.rs b/src/libstd/unstable/mutex.rs
index 3e7a861b385..5b2fac8e74e 100644
--- a/src/libstd/unstable/mutex.rs
+++ b/src/libstd/unstable/mutex.rs
@@ -48,7 +48,7 @@
 #[allow(non_camel_case_types)];
 
 use libc::c_void;
-use unstable::atomics;
+use sync::atomics;
 
 pub struct Mutex {
     // pointers for the lock/cond handles, atomically updated
@@ -333,12 +333,12 @@ mod test {
     fn somke_cond() {
         static mut lock: Mutex = MUTEX_INIT;
         unsafe {
+            lock.lock();
             let t = do Thread::start {
                 lock.lock();
                 lock.signal();
                 lock.unlock();
             };
-            lock.lock();
             lock.wait();
             lock.unlock();
             t.join();
diff --git a/src/libstd/unstable/stack.rs b/src/libstd/unstable/stack.rs
new file mode 100644
index 00000000000..d6cd690eaa9
--- /dev/null
+++ b/src/libstd/unstable/stack.rs
@@ -0,0 +1,275 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Rust stack-limit management
+//!
+//! Currently Rust uses a segmented-stack-like scheme in order to detect stack
+//! overflow for rust tasks. In this scheme, the prologue of all functions are
+//! preceded with a check to see whether the current stack limits are being
+//! exceeded.
+//!
+//! This module provides the functionality necessary in order to manage these
+//! stack limits (which are stored in platform-specific locations). The
+//! functions here are used at the borders of the task lifetime in order to
+//! manage these limits.
+//!
+//! This function is an unstable module because this scheme for stack overflow
+//! detection is not guaranteed to continue in the future. Usage of this module
+//! is discouraged unless absolutely necessary.
+
+static RED_ZONE: uint = 20 * 1024;
+
+/// This function is invoked from rust's current __morestack function. Segmented
+/// stacks are currently not enabled as segmented stacks, but rather one giant
+/// stack segment. This means that whenever we run out of stack, we want to
+/// truly consider it to be stack overflow rather than allocating a new stack.
+#[no_mangle]      // - this is called from C code
+#[no_split_stack] // - it would be sad for this function to trigger __morestack
+#[doc(hidden)]    // - Function must be `pub` to get exported, but it's
+                  //   irrelevant for documentation purposes.
+#[cfg(not(test))] // in testing, use the original libstd's version
+pub extern "C" fn rust_stack_exhausted() {
+    use rt::task::Task;
+    use option::None;
+    use rt::local::Local;
+    use unstable::intrinsics;
+
+    unsafe {
+        // We're calling this function because the stack just ran out. We need
+        // to call some other rust functions, but if we invoke the functions
+        // right now it'll just trigger this handler being called again. In
+        // order to alleviate this, we move the stack limit to be inside of the
+        // red zone that was allocated for exactly this reason.
+        let limit = get_sp_limit();
+        record_sp_limit(limit - RED_ZONE / 2);
+
+        // This probably isn't the best course of action. Ideally one would want
+        // to unwind the stack here instead of just aborting the entire process.
+        // This is a tricky problem, however. There's a few things which need to
+        // be considered:
+        //
+        //  1. We're here because of a stack overflow, yet unwinding will run
+        //     destructors and hence arbitrary code. What if that code overflows
+        //     the stack? One possibility is to use the above allocation of an
+        //     extra 10k to hope that we don't hit the limit, and if we do then
+        //     abort the whole program. Not the best, but kind of hard to deal
+        //     with unless we want to switch stacks.
+        //
+        //  2. LLVM will optimize functions based on whether they can unwind or
+        //     not. It will flag functions with 'nounwind' if it believes that
+        //     the function cannot trigger unwinding, but if we do unwind on
+        //     stack overflow then it means that we could unwind in any function
+        //     anywhere. We would have to make sure that LLVM only places the
+        //     nounwind flag on functions which don't call any other functions.
+        //
+        //  3. The function that overflowed may have owned arguments. These
+        //     arguments need to have their destructors run, but we haven't even
+        //     begun executing the function yet, so unwinding will not run the
+        //     any landing pads for these functions. If this is ignored, then
+        //     the arguments will just be leaked.
+        //
+        // Exactly what to do here is a very delicate topic, and is possibly
+        // still up in the air for what exactly to do. Some relevant issues:
+        //
+        //  #3555 - out-of-stack failure leaks arguments
+        //  #3695 - should there be a stack limit?
+        //  #9855 - possible strategies which could be taken
+        //  #9854 - unwinding on windows through __morestack has never worked
+        //  #2361 - possible implementation of not using landing pads
+
+        let mut task = Local::borrow(None::<Task>);
+        let n = task.get().name.as_ref()
+                    .map(|n| n.as_slice()).unwrap_or("<unnamed>");
+
+        // See the message below for why this is not emitted to the
+        // task's logger. This has the additional conundrum of the
+        // logger may not be initialized just yet, meaning that an FFI
+        // call would happen to initialized it (calling out to libuv),
+        // and the FFI call needs 2MB of stack when we just ran out.
+        println!("task '{}' has overflowed its stack", n);
+
+        intrinsics::abort();
+    }
+}
+
+#[inline(always)]
+pub unsafe fn record_stack_bounds(stack_lo: uint, stack_hi: uint) {
+    // When the old runtime had segmented stacks, it used a calculation that was
+    // "limit + RED_ZONE + FUDGE". The red zone was for things like dynamic
+    // symbol resolution, llvm function calls, etc. In theory this red zone
+    // value is 0, but it matters far less when we have gigantic stacks because
+    // we don't need to be so exact about our stack budget. The "fudge factor"
+    // was because LLVM doesn't emit a stack check for functions < 256 bytes in
+    // size. Again though, we have giant stacks, so we round all these
+    // calculations up to the nice round number of 20k.
+    record_sp_limit(stack_lo + RED_ZONE);
+
+    return target_record_stack_bounds(stack_lo, stack_hi);
+
+    #[cfg(not(windows))] #[cfg(not(target_arch = "x86_64"))] #[inline(always)]
+    unsafe fn target_record_stack_bounds(_stack_lo: uint, _stack_hi: uint) {}
+    #[cfg(windows, target_arch = "x86_64")] #[inline(always)]
+    unsafe fn target_record_stack_bounds(stack_lo: uint, stack_hi: uint) {
+        // Windows compiles C functions which may check the stack bounds. This
+        // means that if we want to perform valid FFI on windows, then we need
+        // to ensure that the stack bounds are what they truly are for this
+        // task. More info can be found at:
+        //   https://github.com/mozilla/rust/issues/3445#issuecomment-26114839
+        //
+        // stack range is at TIB: %gs:0x08 (top) and %gs:0x10 (bottom)
+        asm!("mov $0, %gs:0x08" :: "r"(stack_hi) :: "volatile");
+        asm!("mov $0, %gs:0x10" :: "r"(stack_lo) :: "volatile");
+    }
+}
+
+/// Records the current limit of the stack as specified by `end`.
+///
+/// This is stored in an OS-dependent location, likely inside of the thread
+/// local storage. The location that the limit is stored is a pre-ordained
+/// location because it's where LLVM has emitted code to check.
+///
+/// Note that this cannot be called under normal circumstances. This function is
+/// changing the stack limit, so upon returning any further function calls will
+/// possibly be triggering the morestack logic if you're not careful.
+///
+/// Also note that this and all of the inside functions are all flagged as
+/// "inline(always)" because they're messing around with the stack limits.  This
+/// would be unfortunate for the functions themselves to trigger a morestack
+/// invocation (if they were an actual function call).
+#[inline(always)]
+pub unsafe fn record_sp_limit(limit: uint) {
+    return target_record_sp_limit(limit);
+
+    // x86-64
+    #[cfg(target_arch = "x86_64", target_os = "macos")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        asm!("movq $$0x60+90*8, %rsi
+              movq $0, %gs:(%rsi)" :: "r"(limit) : "rsi" : "volatile")
+    }
+    #[cfg(target_arch = "x86_64", target_os = "linux")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        asm!("movq $0, %fs:112" :: "r"(limit) :: "volatile")
+    }
+    #[cfg(target_arch = "x86_64", target_os = "win32")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        // see: http://en.wikipedia.org/wiki/Win32_Thread_Information_Block
+        // store this inside of the "arbitrary data slot", but double the size
+        // because this is 64 bit instead of 32 bit
+        asm!("movq $0, %gs:0x28" :: "r"(limit) :: "volatile")
+    }
+    #[cfg(target_arch = "x86_64", target_os = "freebsd")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        asm!("movq $0, %fs:24" :: "r"(limit) :: "volatile")
+    }
+
+    // x86
+    #[cfg(target_arch = "x86", target_os = "macos")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        asm!("movl $$0x48+90*4, %eax
+              movl $0, %gs:(%eax)" :: "r"(limit) : "eax" : "volatile")
+    }
+    #[cfg(target_arch = "x86", target_os = "linux")]
+    #[cfg(target_arch = "x86", target_os = "freebsd")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        asm!("movl $0, %gs:48" :: "r"(limit) :: "volatile")
+    }
+    #[cfg(target_arch = "x86", target_os = "win32")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        // see: http://en.wikipedia.org/wiki/Win32_Thread_Information_Block
+        // store this inside of the "arbitrary data slot"
+        asm!("movl $0, %fs:0x14" :: "r"(limit) :: "volatile")
+    }
+
+    // mips, arm - Some brave soul can port these to inline asm, but it's over
+    //             my head personally
+    #[cfg(target_arch = "mips")]
+    #[cfg(target_arch = "arm")] #[inline(always)]
+    unsafe fn target_record_sp_limit(limit: uint) {
+        use libc::c_void;
+        return record_sp_limit(limit as *c_void);
+        extern {
+            fn record_sp_limit(limit: *c_void);
+        }
+    }
+}
+
+/// The counterpart of the function above, this function will fetch the current
+/// stack limit stored in TLS.
+///
+/// Note that all of these functions are meant to be exact counterparts of their
+/// brethren above, except that the operands are reversed.
+///
+/// As with the setter, this function does not have a __morestack header and can
+/// therefore be called in a "we're out of stack" situation.
+#[inline(always)]
+pub unsafe fn get_sp_limit() -> uint {
+    return target_get_sp_limit();
+
+    // x86-64
+    #[cfg(target_arch = "x86_64", target_os = "macos")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movq $$0x60+90*8, %rsi
+              movq %gs:(%rsi), $0" : "=r"(limit) :: "rsi" : "volatile");
+        return limit;
+    }
+    #[cfg(target_arch = "x86_64", target_os = "linux")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movq %fs:112, $0" : "=r"(limit) ::: "volatile");
+        return limit;
+    }
+    #[cfg(target_arch = "x86_64", target_os = "win32")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movq %gs:0x28, $0" : "=r"(limit) ::: "volatile");
+        return limit;
+    }
+    #[cfg(target_arch = "x86_64", target_os = "freebsd")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movq %fs:24, $0" : "=r"(limit) ::: "volatile");
+        return limit;
+    }
+
+    // x86
+    #[cfg(target_arch = "x86", target_os = "macos")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movl $$0x48+90*4, %eax
+              movl %gs:(%eax), $0" : "=r"(limit) :: "eax" : "volatile");
+        return limit;
+    }
+    #[cfg(target_arch = "x86", target_os = "linux")]
+    #[cfg(target_arch = "x86", target_os = "freebsd")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movl %gs:48, $0" : "=r"(limit) ::: "volatile");
+        return limit;
+    }
+    #[cfg(target_arch = "x86", target_os = "win32")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        let limit;
+        asm!("movl %fs:0x14, $0" : "=r"(limit) ::: "volatile");
+        return limit;
+    }
+
+    // mips, arm - Some brave soul can port these to inline asm, but it's over
+    //             my head personally
+    #[cfg(target_arch = "mips")]
+    #[cfg(target_arch = "arm")] #[inline(always)]
+    unsafe fn target_get_sp_limit() -> uint {
+        use libc::c_void;
+        return get_sp_limit() as uint;
+        extern {
+            fn get_sp_limit() -> *c_void;
+        }
+    }
+}
diff --git a/src/libstd/unstable/sync.rs b/src/libstd/unstable/sync.rs
index 50fae1e0239..687efea939b 100644
--- a/src/libstd/unstable/sync.rs
+++ b/src/libstd/unstable/sync.rs
@@ -8,353 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use cast;
-use comm::{Chan, Port};
-use ptr;
-use option::{Option,Some,None};
-use task;
-use unstable::atomics::{AtomicOption,AtomicUint,Acquire,Release,Relaxed,SeqCst};
-use unstable::mutex::Mutex;
-use ops::Drop;
 use clone::Clone;
 use kinds::Send;
-use vec;
-
-/// An atomically reference counted pointer.
-///
-/// Enforces no shared-memory safety.
-//#[unsafe_no_drop_flag] FIXME: #9758
-pub struct UnsafeArc<T> {
-    data: *mut ArcData<T>,
-}
-
-pub enum UnsafeArcUnwrap<T> {
-    UnsafeArcSelf(UnsafeArc<T>),
-    UnsafeArcT(T)
-}
-
-#[cfg(test)]
-impl<T> UnsafeArcUnwrap<T> {
-    fn expect_t(self, msg: &'static str) -> T {
-        match self {
-            UnsafeArcSelf(_) => fail!(msg),
-            UnsafeArcT(t) => t
-        }
-    }
-
-    fn is_self(&self) -> bool {
-        match *self {
-            UnsafeArcSelf(_) => true,
-            UnsafeArcT(_) => false
-        }
-    }
-}
-
-struct ArcData<T> {
-    count: AtomicUint,
-    // An unwrapper uses this protocol to communicate with the "other" task that
-    // drops the last refcount on an arc. Unfortunately this can't be a proper
-    // pipe protocol because the unwrapper has to access both stages at once.
-    // FIXME(#7544): Maybe use AtomicPtr instead (to avoid xchg in take() later)?
-    unwrapper: AtomicOption<(Chan<()>, Port<bool>)>,
-    // FIXME(#3224) should be able to make this non-option to save memory
-    data: Option<T>,
-}
-
-unsafe fn new_inner<T: Send>(data: T, refcount: uint) -> *mut ArcData<T> {
-    let data = ~ArcData { count: AtomicUint::new(refcount),
-                          unwrapper: AtomicOption::empty(),
-                          data: Some(data) };
-    cast::transmute(data)
-}
-
-/// A helper object used by `UnsafeArc::unwrap`.
-struct ChannelAndDataGuard<T> {
-    channel: Option<Chan<bool>>,
-    data: Option<~ArcData<T>>,
-}
-
-#[unsafe_destructor]
-impl<T> Drop for ChannelAndDataGuard<T> {
-    fn drop(&mut self) {
-        if task::failing() {
-            // Killed during wait. Because this might happen while
-            // someone else still holds a reference, we can't free
-            // the data now; the "other" last refcount will free it.
-            unsafe {
-                let channel = self.channel.take_unwrap();
-                let data = self.data.take_unwrap();
-                channel.send(false);
-                cast::forget(data);
-            }
-        }
-    }
-}
-
-impl<T> ChannelAndDataGuard<T> {
-    fn unwrap(mut self) -> (Chan<bool>, ~ArcData<T>) {
-        (self.channel.take_unwrap(), self.data.take_unwrap())
-    }
-}
-
-impl<T: Send> UnsafeArc<T> {
-    pub fn new(data: T) -> UnsafeArc<T> {
-        unsafe { UnsafeArc { data: new_inner(data, 1) } }
-    }
-
-    /// As new(), but returns an extra pre-cloned handle.
-    pub fn new2(data: T) -> (UnsafeArc<T>, UnsafeArc<T>) {
-        unsafe {
-            let ptr = new_inner(data, 2);
-            (UnsafeArc { data: ptr }, UnsafeArc { data: ptr })
-        }
-    }
-
-    /// As new(), but returns a vector of as many pre-cloned handles as requested.
-    pub fn newN(data: T, num_handles: uint) -> ~[UnsafeArc<T>] {
-        unsafe {
-            if num_handles == 0 {
-                ~[] // need to free data here
-            } else {
-                let ptr = new_inner(data, num_handles);
-                vec::from_fn(num_handles, |_| UnsafeArc { data: ptr })
-            }
-        }
-    }
-
-    /// As newN(), but from an already-existing handle. Uses one xadd.
-    pub fn cloneN(self, num_handles: uint) -> ~[UnsafeArc<T>] {
-        if num_handles == 0 {
-            ~[] // The "num_handles - 1" trick (below) fails in the 0 case.
-        } else {
-            unsafe {
-                // Minus one because we are recycling the given handle's refcount.
-                let old_count = (*self.data).count.fetch_add(num_handles - 1, Acquire);
-                // let old_count = (*self.data).count.fetch_add(num_handles, Acquire);
-                assert!(old_count >= 1);
-                let ptr = self.data;
-                cast::forget(self); // Don't run the destructor on this handle.
-                vec::from_fn(num_handles, |_| UnsafeArc { data: ptr })
-            }
-        }
-    }
-
-    #[inline]
-    pub fn get(&self) -> *mut T {
-        unsafe {
-            assert!((*self.data).count.load(Relaxed) > 0);
-            let r: *mut T = (*self.data).data.get_mut_ref();
-            return r;
-        }
-    }
-
-    #[inline]
-    pub fn get_immut(&self) -> *T {
-        unsafe {
-            assert!((*self.data).count.load(Relaxed) > 0);
-            let r: *T = (*self.data).data.get_ref();
-            return r;
-        }
-    }
-
-    /// Wait until all other handles are dropped, then retrieve the enclosed
-    /// data. See extra::arc::Arc for specific semantics documentation.
-    /// If called when the task is already unkillable, unwrap will unkillably
-    /// block; otherwise, an unwrapping task can be killed by linked failure.
-    pub fn unwrap(self) -> T {
-        unsafe {
-            let mut this = self;
-            // The ~ dtor needs to run if this code succeeds.
-            let mut data: ~ArcData<T> = cast::transmute(this.data);
-            // Set up the unwrap protocol.
-            let (p1,c1) = Chan::new(); // ()
-            let (p2,c2) = Chan::new(); // bool
-            // Try to put our server end in the unwrapper slot.
-            // This needs no barrier -- it's protected by the release barrier on
-            // the xadd, and the acquire+release barrier in the destructor's xadd.
-            if data.unwrapper.fill(~(c1,p2), Relaxed).is_none() {
-                // Got in. Tell this handle's destructor not to run (we are now it).
-                this.data = ptr::mut_null();
-                // Drop our own reference.
-                let old_count = data.count.fetch_sub(1, Release);
-                assert!(old_count >= 1);
-                if old_count == 1 {
-                    // We were the last owner. Can unwrap immediately.
-                    // AtomicOption's destructor will free the server endpoint.
-                    // FIXME(#3224): it should be like this
-                    // let ~ArcData { data: user_data, _ } = data;
-                    // user_data
-                    data.data.take_unwrap()
-                } else {
-                    // The *next* person who sees the refcount hit 0 will wake us.
-                    let c2_and_data = ChannelAndDataGuard {
-                        channel: Some(c2),
-                        data: Some(data),
-                    };
-                    p1.recv();
-                    // Got here. Back in the 'unkillable' without getting killed.
-                    let (c2, data) = c2_and_data.unwrap();
-                    c2.send(true);
-                    // FIXME(#3224): it should be like this
-                    // let ~ArcData { data: user_data, _ } = data;
-                    // user_data
-                    let mut data = data;
-                    data.data.take_unwrap()
-                }
-            } else {
-                // If 'put' returns the server end back to us, we were rejected;
-                // someone else was trying to unwrap. Avoid guaranteed deadlock.
-                cast::forget(data);
-                fail!("Another task is already unwrapping this Arc!");
-            }
-        }
-    }
-
-    /// As unwrap above, but without blocking. Returns 'UnsafeArcSelf(self)' if this is
-    /// not the last reference; 'UnsafeArcT(unwrapped_data)' if so.
-    pub fn try_unwrap(mut self) -> UnsafeArcUnwrap<T> {
-        unsafe {
-            // The ~ dtor needs to run if this code succeeds.
-            let mut data: ~ArcData<T> = cast::transmute(self.data);
-            // This can of course race with anybody else who has a handle, but in
-            // such a case, the returned count will always be at least 2. If we
-            // see 1, no race was possible. All that matters is 1 or not-1.
-            let count = data.count.load(Acquire);
-            assert!(count >= 1);
-            // The more interesting race is one with an unwrapper. They may have
-            // already dropped their count -- but if so, the unwrapper pointer
-            // will have been set first, which the barriers ensure we will see.
-            // (Note: using is_empty(), not take(), to not free the unwrapper.)
-            if count == 1 && data.unwrapper.is_empty(Acquire) {
-                // Tell this handle's destructor not to run (we are now it).
-                self.data = ptr::mut_null();
-                // FIXME(#3224) as above
-                UnsafeArcT(data.data.take_unwrap())
-            } else {
-                cast::forget(data);
-                UnsafeArcSelf(self)
-            }
-        }
-    }
-}
-
-impl<T: Send> Clone for UnsafeArc<T> {
-    fn clone(&self) -> UnsafeArc<T> {
-        unsafe {
-            // This barrier might be unnecessary, but I'm not sure...
-            let old_count = (*self.data).count.fetch_add(1, Acquire);
-            assert!(old_count >= 1);
-            return UnsafeArc { data: self.data };
-        }
-    }
-}
-
-#[unsafe_destructor]
-impl<T> Drop for UnsafeArc<T>{
-    fn drop(&mut self) {
-        unsafe {
-            // Happens when destructing an unwrapper's handle and from `#[unsafe_no_drop_flag]`
-            if self.data.is_null() {
-                return
-            }
-            let mut data: ~ArcData<T> = cast::transmute(self.data);
-            // Must be acquire+release, not just release, to make sure this
-            // doesn't get reordered to after the unwrapper pointer load.
-            let old_count = data.count.fetch_sub(1, SeqCst);
-            assert!(old_count >= 1);
-            if old_count == 1 {
-                // Were we really last, or should we hand off to an
-                // unwrapper? It's safe to not xchg because the unwrapper
-                // will set the unwrap lock *before* dropping his/her
-                // reference. In effect, being here means we're the only
-                // *awake* task with the data.
-                match data.unwrapper.take(Acquire) {
-                    Some(~(message, response)) => {
-                        // Send 'ready' and wait for a response.
-                        message.send(());
-                        // Unkillable wait. Message guaranteed to come.
-                        if response.recv() {
-                            // Other task got the data.
-                            cast::forget(data);
-                        } else {
-                            // Other task was killed. drop glue takes over.
-                        }
-                    }
-                    None => {
-                        // drop glue takes over.
-                    }
-                }
-            } else {
-                cast::forget(data);
-            }
-        }
-    }
-}
-
-
-/****************************************************************************/
-
-pub struct AtomicGuard {
-    on: bool,
-}
-
-impl Drop for AtomicGuard {
-    fn drop(&mut self) {
-        use rt::task::{Task, GreenTask, SchedTask};
-        use rt::local::Local;
-
-        if self.on {
-            unsafe {
-                let task_opt: Option<*mut Task> = Local::try_unsafe_borrow();
-                match task_opt {
-                    Some(t) => {
-                        match (*t).task_type {
-                            GreenTask(_) => (*t).death.allow_deschedule(),
-                            SchedTask => {}
-                        }
-                    }
-                    None => {}
-                }
-            }
-        }
-    }
-}
-
-/**
- * Enables a runtime assertion that no operation while the returned guard is
- * live uses scheduler operations (deschedule, recv, spawn, etc). This is for
- * use with pthread mutexes, which may block the entire scheduler thread,
- * rather than just one task, and is hence prone to deadlocks if mixed with
- * descheduling.
- *
- * NOTE: THIS DOES NOT PROVIDE LOCKING, or any sort of critical-section
- * synchronization whatsoever. It only makes sense to use for CPU-local issues.
- */
-// FIXME(#8140) should not be pub
-pub unsafe fn atomic() -> AtomicGuard {
-    use rt::task::{Task, GreenTask, SchedTask};
-    use rt::local::Local;
-
-    let task_opt: Option<*mut Task> = Local::try_unsafe_borrow();
-    match task_opt {
-        Some(t) => {
-            match (*t).task_type {
-                GreenTask(_) => {
-                    (*t).death.inhibit_deschedule();
-                    return AtomicGuard {
-                        on: true,
-                    };
-                }
-                SchedTask => {}
-            }
-        }
-        None => {}
-    }
-
-    AtomicGuard {
-        on: false,
-    }
-}
+use ops::Drop;
+use option::{Option,Some,None};
+use sync::arc::UnsafeArc;
+use unstable::mutex::Mutex;
 
 pub struct LittleLock {
     priv l: Mutex,
@@ -496,37 +155,14 @@ impl<T:Send> Exclusive<T> {
             l.wait();
         }
     }
-
-    pub fn unwrap(self) -> T {
-        let Exclusive { x: x } = self;
-        // Someday we might need to unkillably unwrap an Exclusive, but not today.
-        let inner = x.unwrap();
-        let ExData { data: user_data, .. } = inner; // will destroy the LittleLock
-        user_data
-    }
 }
 
 #[cfg(test)]
 mod tests {
     use option::*;
     use prelude::*;
-    use super::{Exclusive, UnsafeArc, atomic};
+    use super::Exclusive;
     use task;
-    use mem::size_of;
-
-    //#[unsafe_no_drop_flag] FIXME: #9758
-    #[ignore]
-    #[test]
-    fn test_size() {
-        assert_eq!(size_of::<UnsafeArc<[int, ..10]>>(), size_of::<*[int, ..10]>());
-    }
-
-    #[test]
-    fn test_atomic() {
-        // NB. The whole runtime will abort on an 'atomic-sleep' violation,
-        // so we can't really test for the converse behaviour.
-        unsafe { let _ = atomic(); } // oughtn't fail
-    }
 
     #[test]
     fn exclusive_new_arc() {
@@ -570,114 +206,4 @@ mod tests {
             x.with(|one| assert_eq!(*one, 1));
         }
     }
-
-    #[test]
-    fn arclike_newN() {
-        // Tests that the many-refcounts-at-once constructors don't leak.
-        let _ = UnsafeArc::new2(~~"hello");
-        let x = UnsafeArc::newN(~~"hello", 0);
-        assert_eq!(x.len(), 0)
-        let x = UnsafeArc::newN(~~"hello", 1);
-        assert_eq!(x.len(), 1)
-        let x = UnsafeArc::newN(~~"hello", 10);
-        assert_eq!(x.len(), 10)
-    }
-
-    #[test]
-    fn arclike_cloneN() {
-        // Tests that the many-refcounts-at-once special-clone doesn't leak.
-        let x = UnsafeArc::new(~~"hello");
-        let x = x.cloneN(0);
-        assert_eq!(x.len(), 0);
-        let x = UnsafeArc::new(~~"hello");
-        let x = x.cloneN(1);
-        assert_eq!(x.len(), 1);
-        let x = UnsafeArc::new(~~"hello");
-        let x = x.cloneN(10);
-        assert_eq!(x.len(), 10);
-    }
-
-    #[test]
-    fn arclike_unwrap_basic() {
-        let x = UnsafeArc::new(~~"hello");
-        assert!(x.unwrap() == ~~"hello");
-    }
-
-    #[test]
-    fn arclike_try_unwrap() {
-        let x = UnsafeArc::new(~~"hello");
-        assert!(x.try_unwrap().expect_t("try_unwrap failed") == ~~"hello");
-    }
-
-    #[test]
-    fn arclike_try_unwrap_fail() {
-        let x = UnsafeArc::new(~~"hello");
-        let x2 = x.clone();
-        let left_x = x.try_unwrap();
-        assert!(left_x.is_self());
-        drop(left_x);
-        assert!(x2.try_unwrap().expect_t("try_unwrap none") == ~~"hello");
-    }
-
-    #[test]
-    fn arclike_try_unwrap_unwrap_race() {
-        // When an unwrap and a try_unwrap race, the unwrapper should always win.
-        let x = UnsafeArc::new(~~"hello");
-        let x2 = x.clone();
-        let (p,c) = Chan::new();
-        do task::spawn {
-            c.send(());
-            assert!(x2.unwrap() == ~~"hello");
-            c.send(());
-        }
-        p.recv();
-        task::deschedule(); // Try to make the unwrapper get blocked first.
-        let left_x = x.try_unwrap();
-        assert!(left_x.is_self());
-        drop(left_x);
-        p.recv();
-    }
-
-    #[test]
-    fn exclusive_new_unwrap_basic() {
-        // Unlike the above, also tests no double-freeing of the LittleLock.
-        let x = Exclusive::new(~~"hello");
-        assert!(x.unwrap() == ~~"hello");
-    }
-
-    #[test]
-    fn exclusive_new_unwrap_contended() {
-        let x = Exclusive::new(~~"hello");
-        let x2 = x.clone();
-        do task::spawn {
-            unsafe { x2.with(|_hello| ()); }
-            task::deschedule();
-        }
-        assert!(x.unwrap() == ~~"hello");
-
-        // Now try the same thing, but with the child task blocking.
-        let x = Exclusive::new(~~"hello");
-        let x2 = x.clone();
-        let mut builder = task::task();
-        let res = builder.future_result();
-        do builder.spawn {
-            assert!(x2.unwrap() == ~~"hello");
-        }
-        // Have to get rid of our reference before blocking.
-        drop(x);
-        res.recv();
-    }
-
-    #[test] #[should_fail]
-    fn exclusive_new_unwrap_conflict() {
-        let x = Exclusive::new(~~"hello");
-        let x2 = x.clone();
-        let mut builder = task::task();
-        let res = builder.future_result();
-        do builder.spawn {
-            assert!(x2.unwrap() == ~~"hello");
-        }
-        assert!(x.unwrap() == ~~"hello");
-        assert!(res.recv().is_ok());
-    }
 }
diff --git a/src/libstd/vec.rs b/src/libstd/vec.rs
index 97d4c2f6d1b..86f28c28f69 100644
--- a/src/libstd/vec.rs
+++ b/src/libstd/vec.rs
@@ -2874,7 +2874,6 @@ impl<A> Extendable<A> for ~[A] {
 
 #[cfg(test)]
 mod tests {
-    use option::{None, Some};
     use mem;
     use vec::*;
     use cmp::*;
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 930d25e7443..aa7e0d0eced 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -606,7 +606,6 @@ impl AstBuilder for @ExtCtxt {
             ~[
                 self.ident_of("std"),
                 self.ident_of("rt"),
-                self.ident_of("task"),
                 self.ident_of("begin_unwind"),
             ],
             ~[
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index a6e45c7e1bb..2c2669e914c 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -740,10 +740,10 @@ pub fn std_macros() -> @str {
             fail!("explicit failure")
         );
         ($msg:expr) => (
-            ::std::rt::task::begin_unwind($msg, file!(), line!())
+            ::std::rt::begin_unwind($msg, file!(), line!())
         );
         ($fmt:expr, $($arg:tt)*) => (
-            ::std::rt::task::begin_unwind(format!($fmt, $($arg)*), file!(), line!())
+            ::std::rt::begin_unwind(format!($fmt, $($arg)*), file!(), line!())
         )
     )
 
diff --git a/src/test/bench/rt-messaging-ping-pong.rs b/src/test/bench/rt-messaging-ping-pong.rs
index 90d81aa7c3e..6eef71622c5 100644
--- a/src/test/bench/rt-messaging-ping-pong.rs
+++ b/src/test/bench/rt-messaging-ping-pong.rs
@@ -1,4 +1,3 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -12,7 +11,6 @@ extern mod extra;
 
 use std::os;
 use std::uint;
-use std::rt::test::spawntask_later;
 
 // This is a simple bench that creates M pairs of of tasks. These
 // tasks ping-pong back and forth over a pair of streams. This is a
@@ -28,7 +26,7 @@ fn ping_pong_bench(n: uint, m: uint) {
         // Create a stream B->A
         let (pb,cb) = Chan::<()>::new();
 
-        do spawntask_later() || {
+        do spawn() || {
             let chan = ca;
             let port = pb;
             n.times(|| {
@@ -37,7 +35,7 @@ fn ping_pong_bench(n: uint, m: uint) {
             })
         }
 
-        do spawntask_later() || {
+        do spawn() || {
             let chan = cb;
             let port = pa;
             n.times(|| {
diff --git a/src/test/bench/rt-parfib.rs b/src/test/bench/rt-parfib.rs
index ab607d9aebc..6e3c42f2a4d 100644
--- a/src/test/bench/rt-parfib.rs
+++ b/src/test/bench/rt-parfib.rs
@@ -12,7 +12,6 @@ extern mod extra;
 
 use std::os;
 use std::uint;
-use std::rt::test::spawntask_later;
 
 // A simple implementation of parfib. One subtree is found in a new
 // task and communicated over a oneshot pipe, the other is found
@@ -24,7 +23,7 @@ fn parfib(n: uint) -> uint {
     }
 
     let (port,chan) = Chan::new();
-    do spawntask_later {
+    do spawn {
         chan.send(parfib(n-1));
     };
     let m2 = parfib(n-2);
diff --git a/src/test/bench/shootout-spectralnorm.rs b/src/test/bench/shootout-spectralnorm.rs
index 87cd01f9aad..8174347e386 100644
--- a/src/test/bench/shootout-spectralnorm.rs
+++ b/src/test/bench/shootout-spectralnorm.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// xfail-test arcs no longer unwrap
+
 extern mod extra;
 
 use std::from_str::FromStr;
diff --git a/src/test/compile-fail/std-uncopyable-atomics.rs b/src/test/compile-fail/std-uncopyable-atomics.rs
index a46dec7830a..57c66974fcd 100644
--- a/src/test/compile-fail/std-uncopyable-atomics.rs
+++ b/src/test/compile-fail/std-uncopyable-atomics.rs
@@ -12,7 +12,7 @@
 
 #[feature(globs)];
 
-use std::unstable::atomics::*;
+use std::sync::atomics::*;
 use std::ptr;
 
 fn main() {
diff --git a/src/test/run-make/bootstrap-from-c-with-uvio/Makefile b/src/test/run-make/bootstrap-from-c-with-green/Makefile
similarity index 100%
rename from src/test/run-make/bootstrap-from-c-with-uvio/Makefile
rename to src/test/run-make/bootstrap-from-c-with-green/Makefile
diff --git a/src/test/run-pass/rt-start-main-thread.rs b/src/test/run-make/bootstrap-from-c-with-green/lib.rs
similarity index 66%
rename from src/test/run-pass/rt-start-main-thread.rs
rename to src/test/run-make/bootstrap-from-c-with-green/lib.rs
index 47a723ce6e1..9a03c772f3a 100644
--- a/src/test/run-pass/rt-start-main-thread.rs
+++ b/src/test/run-make/bootstrap-from-c-with-green/lib.rs
@@ -8,14 +8,18 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// xfail-fast
+#[crate_id="boot#0.1"];
+#[crate_type="lib"];
+#[no_uv];
 
-#[start]
-fn start(argc: int, argv: **u8) -> int {
-    do std::rt::start_on_main_thread(argc, argv) {
-        info!("running on main thread");
+extern mod rustuv;
+extern mod green;
+
+#[no_mangle] // this needs to get called from C
+pub extern "C" fn foo(argc: int, argv: **u8) -> int {
+    do green::start(argc, argv) {
         do spawn {
-            info!("running on another thread");
+            println!("hello");
         }
     }
 }
diff --git a/src/test/run-make/bootstrap-from-c-with-uvio/main.c b/src/test/run-make/bootstrap-from-c-with-green/main.c
similarity index 100%
rename from src/test/run-make/bootstrap-from-c-with-uvio/main.c
rename to src/test/run-make/bootstrap-from-c-with-green/main.c
diff --git a/src/test/run-make/bootstrap-from-c-with-native/Makefile b/src/test/run-make/bootstrap-from-c-with-native/Makefile
new file mode 100644
index 00000000000..7f466573da7
--- /dev/null
+++ b/src/test/run-make/bootstrap-from-c-with-native/Makefile
@@ -0,0 +1,9 @@
+-include ../tools.mk
+
+all:
+	$(RUSTC) lib.rs -Z gen-crate-map
+	ln -nsf $(call DYLIB,boot-*) $(call DYLIB,boot)
+	$(CC) main.c -o $(call RUN,main) -lboot -Wl,-rpath,$(TMPDIR)
+	$(call RUN,main)
+	rm $(call DYLIB,boot)
+	$(call FAIL,main)
diff --git a/src/test/run-make/bootstrap-from-c-with-uvio/lib.rs b/src/test/run-make/bootstrap-from-c-with-native/lib.rs
similarity index 89%
rename from src/test/run-make/bootstrap-from-c-with-uvio/lib.rs
rename to src/test/run-make/bootstrap-from-c-with-native/lib.rs
index 06a06c967f4..d0639d45fa5 100644
--- a/src/test/run-make/bootstrap-from-c-with-uvio/lib.rs
+++ b/src/test/run-make/bootstrap-from-c-with-native/lib.rs
@@ -10,14 +10,13 @@
 
 #[crate_id="boot#0.1"];
 #[crate_type="lib"];
+#[no_uv];
 
-extern mod rustuv; // pull in uvio
-
-use std::rt;
+extern mod native;
 
 #[no_mangle] // this needs to get called from C
 pub extern "C" fn foo(argc: int, argv: **u8) -> int {
-    do rt::start(argc, argv) {
+    do native::start(argc, argv) {
         do spawn {
             println!("hello");
         }
diff --git a/src/test/run-pass/native-print-no-uv.rs b/src/test/run-make/bootstrap-from-c-with-native/main.c
similarity index 75%
rename from src/test/run-pass/native-print-no-uv.rs
rename to src/test/run-make/bootstrap-from-c-with-native/main.c
index d3b6d605984..1872c1ea43b 100644
--- a/src/test/run-pass/native-print-no-uv.rs
+++ b/src/test/run-make/bootstrap-from-c-with-native/main.c
@@ -8,10 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// xfail-fast
+// this is the rust entry point that we're going to call.
+int foo(int argc, char *argv[]);
 
-#[no_uv];
-
-fn main() {
-    println!("hello");
+int main(int argc, char *argv[]) {
+  return foo(argc, argv);
 }
diff --git a/src/test/run-pass/core-rt-smoke.rs b/src/test/run-pass/core-rt-smoke.rs
deleted file mode 100644
index 6e3d9629da0..00000000000
--- a/src/test/run-pass/core-rt-smoke.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// xfail-fast
-
-// A simple test of starting the runtime manually
-
-#[start]
-fn start(argc: int, argv: **u8) -> int {
-    do std::rt::start(argc, argv) {
-        info!("creating my own runtime is joy");
-    }
-}
diff --git a/src/test/run-pass/spawning-with-debug.rs b/src/test/run-pass/spawning-with-debug.rs
index 76975d15c1d..f8094f9fdb9 100644
--- a/src/test/run-pass/spawning-with-debug.rs
+++ b/src/test/run-pass/spawning-with-debug.rs
@@ -17,6 +17,5 @@ use std::task;
 
 fn main() {
     let mut t = task::task();
-    t.sched_mode(task::SingleThreaded);
     t.spawn(proc() ());
 }
diff --git a/src/test/run-pass/use.rs b/src/test/run-pass/use.rs
index ddd4b10fd5c..013487e5803 100644
--- a/src/test/run-pass/use.rs
+++ b/src/test/run-pass/use.rs
@@ -10,6 +10,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// xfail-fast
+
 #[allow(unused_imports)];
 
 #[no_std];
@@ -25,4 +27,5 @@ mod baz {
     pub use x = std::str;
 }
 
-pub fn main() { }
+#[start]
+pub fn start(_: int, _: **u8) -> int { 0 }