diff --git a/src/libcore/os.rs b/src/libcore/os.rs
index a1d562926e2..bb22c2137dc 100644
--- a/src/libcore/os.rs
+++ b/src/libcore/os.rs
@@ -24,6 +24,7 @@ import option::{some, none};
 
 import getcwd = rustrt::rust_getcwd;
 import consts::*;
+import task::task_builder;
 
 export close, fclose, fsync_fd, waitpid;
 export env, getenv, setenv, fdopen, pipe;
@@ -160,19 +161,14 @@ mod global_env {
 
     fn get_global_env_chan() -> comm::chan<msg> {
         let global_ptr = rustrt::rust_global_env_chan_ptr();
-        let builder_fn = || {
-            let builder = task::builder();
-            task::unsupervise(builder);
-
+        let task_build_fn = || {
             // FIXME (#2621): This would be a good place to use a very small
             // foreign stack
-            task::set_sched_mode(builder, task::single_threaded);
-
-            builder
+            task::task().sched_mode(task::single_threaded).unlinked()
         };
         unsafe {
             priv::chan_from_global_ptr(
-                global_ptr, builder_fn, global_env_task)
+                global_ptr, task_build_fn, global_env_task)
         }
     }
 
diff --git a/src/libcore/priv.rs b/src/libcore/priv.rs
index 010717c3445..b126ac64bdd 100644
--- a/src/libcore/priv.rs
+++ b/src/libcore/priv.rs
@@ -3,6 +3,7 @@
 export chan_from_global_ptr, weaken_task;
 
 import compare_and_swap = rustrt::rust_compare_and_swap_ptr;
+import task::task_builder;
 
 type rust_port_id = uint;
 
@@ -23,7 +24,7 @@ type global_ptr = *libc::uintptr_t;
  */
 unsafe fn chan_from_global_ptr<T: send>(
     global: global_ptr,
-    builder: fn() -> task::builder,
+    task_fn: fn() -> task::task_builder,
     +f: fn~(comm::port<T>)
 ) -> comm::chan<T> {
 
@@ -41,7 +42,7 @@ unsafe fn chan_from_global_ptr<T: send>(
 
         let setup_po = comm::port();
         let setup_ch = comm::chan(setup_po);
-        let setup_ch = do task::run_listener(builder()) |setup_po| {
+        let setup_ch = do task_fn().spawn_listener |setup_po| {
             let po = comm::port::<T>();
             let ch = comm::chan(po);
             comm::send(setup_ch, ch);
@@ -92,7 +93,7 @@ fn test_from_global_chan1() {
 
     // Create the global channel, attached to a new task
     let ch = unsafe {
-        do chan_from_global_ptr(globchanp, task::builder) |po| {
+        do chan_from_global_ptr(globchanp, task::task) |po| {
             let ch = comm::recv(po);
             comm::send(ch, true);
             let ch = comm::recv(po);
@@ -106,7 +107,7 @@ fn test_from_global_chan1() {
 
     // This one just reuses the previous channel
     let ch = unsafe {
-        do chan_from_global_ptr(globchanp, task::builder) |po| {
+        do chan_from_global_ptr(globchanp, task::task) |po| {
             let ch = comm::recv(po);
             comm::send(ch, false);
         }
@@ -135,7 +136,7 @@ fn test_from_global_chan2() {
             do task::spawn {
                 let ch = unsafe {
                     do chan_from_global_ptr(
-                        globchanp, task::builder) |po| {
+                        globchanp, task::task) |po| {
 
                         for uint::range(0u, 10u) |_j| {
                             let ch = comm::recv(po);
diff --git a/src/libstd/uv_global_loop.rs b/src/libstd/uv_global_loop.rs
index 4a7962a977f..08096135952 100644
--- a/src/libstd/uv_global_loop.rs
+++ b/src/libstd/uv_global_loop.rs
@@ -8,6 +8,7 @@ import get_gl = get;
 import iotask::{iotask, spawn_iotask};
 import priv::{chan_from_global_ptr, weaken_task};
 import comm::{port, chan, methods, select2, listen};
+import task::task_builder;
 import either::{left, right};
 
 extern mod rustrt {
@@ -39,10 +40,7 @@ fn get_monitor_task_gl() -> iotask unsafe {
            monitor_loop_chan_ptr);
 
     let builder_fn = || {
-        let builder = task::builder();
-        task::unsupervise(builder);
-        task::set_sched_mode(builder, task::single_threaded);
-        builder
+        task::task().sched_mode(task::single_threaded).unlinked()
     };
 
     #debug("before priv::chan_from_global_ptr");
@@ -86,8 +84,7 @@ fn get_monitor_task_gl() -> iotask unsafe {
 }
 
 fn spawn_loop() -> iotask unsafe {
-    let builder = task::builder();
-    do task::add_wrapper(builder) |task_body| {
+    let builder = do task::task().add_wrapper |task_body| {
         fn~(move task_body) {
             // The I/O loop task also needs to be weak so it doesn't keep
             // the runtime alive
@@ -102,7 +99,7 @@ fn spawn_loop() -> iotask unsafe {
                 #debug("global libuv task is leaving weakened state");
             }
         }
-    }
+    };
     spawn_iotask(builder)
 }
 
diff --git a/src/libstd/uv_iotask.rs b/src/libstd/uv_iotask.rs
index d049c6f7c7b..5566c0c8f0f 100644
--- a/src/libstd/uv_iotask.rs
+++ b/src/libstd/uv_iotask.rs
@@ -13,6 +13,7 @@ export exit;
 import libc::c_void;
 import ptr::addr_of;
 import comm::{port, chan, methods, listen};
+import task::task_builder;
 import ll = uv_ll;
 
 /// Used to abstract-away direct interaction with a libuv loop.
@@ -23,13 +24,11 @@ enum iotask {
     })
 }
 
-fn spawn_iotask(-builder: task::builder) -> iotask {
-
-    task::set_sched_mode(builder, task::single_threaded);
+fn spawn_iotask(-task: task::task_builder) -> iotask {
 
     do listen |iotask_ch| {
 
-        do task::run(copy(builder)) {
+        do task.sched_mode(task::single_threaded).spawn {
             #debug("entering libuv task");
             run_loop(iotask_ch);
             #debug("libuv task exiting");