diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index 809757aaf4d..66143b40d52 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -169,7 +169,7 @@ fn with_env_lock<T>(f: || -> T) -> T {
 ///
 /// Invalid UTF-8 bytes are replaced with \uFFFD. See `str::from_utf8_lossy()`
 /// for details.
-pub fn env() -> ~[(~str,~str)] {
+pub fn env() -> Vec<(~str,~str)> {
     env_as_bytes().move_iter().map(|(k,v)| {
         let k = str::from_utf8_lossy(k).into_owned();
         let v = str::from_utf8_lossy(v).into_owned();
@@ -179,7 +179,7 @@ pub fn env() -> ~[(~str,~str)] {
 
 /// Returns a vector of (variable, value) byte-vector pairs for all the
 /// environment variables of the current process.
-pub fn env_as_bytes() -> ~[(~[u8],~[u8])] {
+pub fn env_as_bytes() -> Vec<(~[u8],~[u8])> {
     unsafe {
         #[cfg(windows)]
         unsafe fn get_env_pairs() -> Vec<~[u8]> {
@@ -224,16 +224,16 @@ pub fn env_as_bytes() -> ~[(~[u8],~[u8])] {
         fn env_convert(input: Vec<~[u8]>) -> Vec<(~[u8], ~[u8])> {
             let mut pairs = Vec::new();
             for p in input.iter() {
-                let vs: ~[&[u8]] = p.splitn(1, |b| *b == '=' as u8).collect();
-                let key = vs[0].to_owned();
-                let val = if vs.len() < 2 { box [] } else { vs[1].to_owned() };
+                let mut it = p.splitn(1, |b| *b == '=' as u8);
+                let key = it.next().unwrap().to_owned();
+                let val = it.next().unwrap_or(&[]).to_owned();
                 pairs.push((key, val));
             }
             pairs
         }
         with_env_lock(|| {
             let unparsed_environ = get_env_pairs();
-            env_convert(unparsed_environ).move_iter().collect()
+            env_convert(unparsed_environ)
         })
     }
 }
@@ -416,7 +416,7 @@ pub fn dll_filename(base: &str) -> ~str {
 pub fn self_exe_name() -> Option<Path> {
 
     #[cfg(target_os = "freebsd")]
-    fn load_self() -> Option<~[u8]> {
+    fn load_self() -> Option<Vec<u8>> {
         unsafe {
             use libc::funcs::bsd44::*;
             use libc::consts::os::extra::*;
@@ -436,23 +436,23 @@ pub fn self_exe_name() -> Option<Path> {
             if err != 0 { return None; }
             if sz == 0 { return None; }
             v.set_len(sz as uint - 1); // chop off trailing NUL
-            Some(v.move_iter().collect())
+            Some(v)
         }
     }
 
     #[cfg(target_os = "linux")]
     #[cfg(target_os = "android")]
-    fn load_self() -> Option<~[u8]> {
+    fn load_self() -> Option<Vec<u8>> {
         use std::io;
 
         match io::fs::readlink(&Path::new("/proc/self/exe")) {
-            Ok(path) => Some(path.as_vec().to_owned()),
+            Ok(path) => Some(path.into_vec()),
             Err(..) => None
         }
     }
 
     #[cfg(target_os = "macos")]
-    fn load_self() -> Option<~[u8]> {
+    fn load_self() -> Option<Vec<u8>> {
         unsafe {
             use libc::funcs::extra::_NSGetExecutablePath;
             let mut sz: u32 = 0;
@@ -462,19 +462,19 @@ pub fn self_exe_name() -> Option<Path> {
             let err = _NSGetExecutablePath(v.as_mut_ptr() as *mut i8, &mut sz);
             if err != 0 { return None; }
             v.set_len(sz as uint - 1); // chop off trailing NUL
-            Some(v.move_iter().collect())
+            Some(v)
         }
     }
 
     #[cfg(windows)]
-    fn load_self() -> Option<~[u8]> {
+    fn load_self() -> Option<Vec<u8>> {
         use str::OwnedStr;
 
         unsafe {
             use os::win32::fill_utf16_buf_and_decode;
             fill_utf16_buf_and_decode(|buf, sz| {
                 libc::GetModuleFileNameW(0u as libc::DWORD, buf, sz)
-            }).map(|s| s.into_bytes())
+            }).map(|s| s.into_strbuf().into_bytes())
         }
     }
 
@@ -789,12 +789,12 @@ pub fn get_exit_status() -> int {
 }
 
 #[cfg(target_os = "macos")]
-unsafe fn load_argc_and_argv(argc: int, argv: **c_char) -> ~[~[u8]] {
+unsafe fn load_argc_and_argv(argc: int, argv: **c_char) -> Vec<~[u8]> {
     use c_str::CString;
 
     Vec::from_fn(argc as uint, |i| {
         CString::new(*argv.offset(i as int), false).as_bytes_no_nul().to_owned()
-    }).move_iter().collect()
+    })
 }
 
 /**
@@ -803,7 +803,7 @@ unsafe fn load_argc_and_argv(argc: int, argv: **c_char) -> ~[~[u8]] {
  * Returns a list of the command line arguments.
  */
 #[cfg(target_os = "macos")]
-fn real_args_as_bytes() -> ~[~[u8]] {
+fn real_args_as_bytes() -> Vec<~[u8]> {
     unsafe {
         let (argc, argv) = (*_NSGetArgc() as int,
                             *_NSGetArgv() as **c_char);
@@ -814,7 +814,7 @@ fn real_args_as_bytes() -> ~[~[u8]] {
 #[cfg(target_os = "linux")]
 #[cfg(target_os = "android")]
 #[cfg(target_os = "freebsd")]
-fn real_args_as_bytes() -> ~[~[u8]] {
+fn real_args_as_bytes() -> Vec<~[u8]> {
     use rt;
 
     match rt::args::clone() {
@@ -824,12 +824,12 @@ fn real_args_as_bytes() -> ~[~[u8]] {
 }
 
 #[cfg(not(windows))]
-fn real_args() -> ~[~str] {
+fn real_args() -> Vec<~str> {
     real_args_as_bytes().move_iter().map(|v| str::from_utf8_lossy(v).into_owned()).collect()
 }
 
 #[cfg(windows)]
-fn real_args() -> ~[~str] {
+fn real_args() -> Vec<~str> {
     use slice;
     use option::Expect;
 
@@ -855,11 +855,11 @@ fn real_args() -> ~[~str] {
         LocalFree(szArgList as *c_void);
     }
 
-    return args.move_iter().collect();
+    return args
 }
 
 #[cfg(windows)]
-fn real_args_as_bytes() -> ~[~[u8]] {
+fn real_args_as_bytes() -> Vec<~[u8]> {
     real_args().move_iter().map(|s| s.into_bytes()).collect()
 }
 
@@ -883,13 +883,13 @@ extern "system" {
 ///
 /// The arguments are interpreted as utf-8, with invalid bytes replaced with \uFFFD.
 /// See `str::from_utf8_lossy` for details.
-pub fn args() -> ~[~str] {
+pub fn args() -> Vec<~str> {
     real_args()
 }
 
 /// Returns the arguments which this program was started with (normally passed
 /// via the command line) as byte vectors.
-pub fn args_as_bytes() -> ~[~[u8]] {
+pub fn args_as_bytes() -> Vec<~[u8]> {
     real_args_as_bytes()
 }
 
diff --git a/src/libstd/rt/args.rs b/src/libstd/rt/args.rs
index ac1692e6bb3..df0f1d8d449 100644
--- a/src/libstd/rt/args.rs
+++ b/src/libstd/rt/args.rs
@@ -21,6 +21,7 @@
 //! FIXME #7756: This has a lot of C glue for lack of globals.
 
 use option::Option;
+use vec::Vec;
 #[cfg(test)] use option::{Some, None};
 #[cfg(test)] use realstd;
 #[cfg(test)] use realargs = realstd::rt::args;
@@ -36,10 +37,10 @@ pub unsafe fn init(argc: int, argv: **u8) { realargs::init(argc, argv) }
 #[cfg(test)]      pub unsafe fn cleanup() { realargs::cleanup() }
 
 /// Take the global arguments from global storage.
-#[cfg(not(test))] pub fn take() -> Option<~[~[u8]]> { imp::take() }
-#[cfg(test)]      pub fn take() -> Option<~[~[u8]]> {
+#[cfg(not(test))] pub fn take() -> Option<Vec<~[u8]>> { imp::take() }
+#[cfg(test)]      pub fn take() -> Option<Vec<~[u8]>> {
     match realargs::take() {
-        realstd::option::Some(a) => Some(a),
+        realstd::option::Some(v) => Some(unsafe{ ::cast::transmute(v) }),
         realstd::option::None => None,
     }
 }
@@ -47,14 +48,14 @@ pub unsafe fn init(argc: int, argv: **u8) { realargs::init(argc, argv) }
 /// Give the global arguments to global storage.
 ///
 /// It is an error if the arguments already exist.
-#[cfg(not(test))] pub fn put(args: ~[~[u8]]) { imp::put(args) }
-#[cfg(test)]      pub fn put(args: ~[~[u8]]) { realargs::put(args) }
+#[cfg(not(test))] pub fn put(args: Vec<~[u8]>) { imp::put(args) }
+#[cfg(test)]      pub fn put(args: Vec<~[u8]>) { realargs::put(unsafe { ::cast::transmute(args) }) }
 
 /// Make a clone of the global arguments.
-#[cfg(not(test))] pub fn clone() -> Option<~[~[u8]]> { imp::clone() }
-#[cfg(test)]      pub fn clone() -> Option<~[~[u8]]> {
+#[cfg(not(test))] pub fn clone() -> Option<Vec<~[u8]>> { imp::clone() }
+#[cfg(test)]      pub fn clone() -> Option<Vec<~[u8]>> {
     match realargs::clone() {
-        realstd::option::Some(a) => Some(a),
+        realstd::option::Some(v) => Some(unsafe { ::cast::transmute(v) }),
         realstd::option::None => None,
     }
 }
@@ -70,6 +71,7 @@ mod imp {
     use owned::Box;
     use unstable::mutex::{StaticNativeMutex, NATIVE_MUTEX_INIT};
     use mem;
+    use vec::Vec;
     #[cfg(not(test))] use ptr::RawPtr;
 
     static mut global_args_ptr: uint = 0;
@@ -87,15 +89,15 @@ mod imp {
         lock.destroy();
     }
 
-    pub fn take() -> Option<~[~[u8]]> {
+    pub fn take() -> Option<Vec<~[u8]>> {
         with_lock(|| unsafe {
             let ptr = get_global_ptr();
             let val = mem::replace(&mut *ptr, None);
-            val.as_ref().map(|s: &Box<~[~[u8]]>| (**s).clone())
+            val.as_ref().map(|s: &Box<Vec<~[u8]>>| (**s).clone())
         })
     }
 
-    pub fn put(args: ~[~[u8]]) {
+    pub fn put(args: Vec<~[u8]>) {
         with_lock(|| unsafe {
             let ptr = get_global_ptr();
             rtassert!((*ptr).is_none());
@@ -103,10 +105,10 @@ mod imp {
         })
     }
 
-    pub fn clone() -> Option<~[~[u8]]> {
+    pub fn clone() -> Option<Vec<~[u8]>> {
         with_lock(|| unsafe {
             let ptr = get_global_ptr();
-            (*ptr).as_ref().map(|s: &Box<~[~[u8]]>| (**s).clone())
+            (*ptr).as_ref().map(|s: &Box<Vec<~[u8]>>| (**s).clone())
         })
     }
 
@@ -117,13 +119,13 @@ mod imp {
         }
     }
 
-    fn get_global_ptr() -> *mut Option<Box<~[~[u8]]>> {
+    fn get_global_ptr() -> *mut Option<Box<Vec<~[u8]>>> {
         unsafe { cast::transmute(&global_args_ptr) }
     }
 
     // Copied from `os`.
     #[cfg(not(test))]
-    unsafe fn load_argc_and_argv(argc: int, argv: **u8) -> ~[~[u8]] {
+    unsafe fn load_argc_and_argv(argc: int, argv: **u8) -> Vec<~[u8]> {
         use c_str::CString;
         use ptr::RawPtr;
         use libc;
@@ -133,7 +135,7 @@ mod imp {
         Vec::from_fn(argc as uint, |i| {
             let cs = CString::new(*(argv as **libc::c_char).offset(i as int), false);
             cs.as_bytes_no_nul().to_owned()
-        }).move_iter().collect()
+        })
     }
 
     #[cfg(test)]
@@ -147,7 +149,7 @@ mod imp {
             // Preserve the actual global state.
             let saved_value = take();
 
-            let expected = box [bytes!("happy").to_owned(), bytes!("today?").to_owned()];
+            let expected = vec![bytes!("happy").to_owned(), bytes!("today?").to_owned()];
 
             put(expected.clone());
             assert!(clone() == Some(expected.clone()));
@@ -170,6 +172,7 @@ mod imp {
 #[cfg(target_os = "win32", not(test))]
 mod imp {
     use option::Option;
+    use vec::Vec;
 
     pub unsafe fn init(_argc: int, _argv: **u8) {
     }
@@ -177,15 +180,15 @@ mod imp {
     pub fn cleanup() {
     }
 
-    pub fn take() -> Option<~[~[u8]]> {
+    pub fn take() -> Option<Vec<~[u8]>> {
         fail!()
     }
 
-    pub fn put(_args: ~[~[u8]]) {
+    pub fn put(_args: Vec<~[u8]>) {
         fail!()
     }
 
-    pub fn clone() -> Option<~[~[u8]]> {
+    pub fn clone() -> Option<Vec<~[u8]>> {
         fail!()
     }
 }