diff --git a/src/argument.rs b/src/argument.rs
index 5b8d15a..abba4e3 100644
--- a/src/argument.rs
+++ b/src/argument.rs
@@ -3,7 +3,7 @@
  * structures.
  */
 
-use std::{cast, str, sys};
+use std::{cast, str, mem};
 use std::libc::c_char;
 
 /// An iterator that can be used to fetch typed arguments from a byte slice
@@ -22,7 +22,7 @@ impl<'self> ArgumentIterator<'self> {
 	pub fn fetch<T> (&mut self) -> &'self T {
 		do self.data.as_imm_buf |dataptr, _| {
 			let value = unsafe { cast::transmute(dataptr.offset(self.pos as int)) };
-			self.pos += sys::size_of::<T>();
+			self.pos += mem::size_of::<T>();
 			assert!(self.pos <= self.data.len(), "trying to get argument behind data");
 			value
 		}
diff --git a/src/request.rs b/src/request.rs
index d86c415..a3abd52 100644
--- a/src/request.rs
+++ b/src/request.rs
@@ -3,7 +3,7 @@
  * wants us to perform.
  */
 
-use std::{cast, sys, vec};
+use std::{cast, mem, vec};
 use std::libc::{dev_t, c_int, mode_t, off_t, size_t};
 use std::libc::{EIO, ENOSYS, EPROTO, ERANGE};
 use argument::ArgumentIterator;
@@ -42,7 +42,7 @@ impl Request {
 		assert!(self.data.capacity() >= MAX_WRITE_SIZE as uint + 4096);
 		// The kernel driver makes sure that we get exactly one request per read
 		let res = se.ch.receive(&mut self.data);
-		if res.is_ok() && self.data.len() < sys::size_of::<fuse_in_header>() {
+		if res.is_ok() && self.data.len() < mem::size_of::<fuse_in_header>() {
 			error!("Short read on FUSE device");
 			Err(EIO)
 		} else {
@@ -57,7 +57,7 @@ impl Request {
 	pub fn dispatch<FS: Filesystem> (&self, se: &mut Session<FS>) {
 		// Every request begins with a fuse_in_header struct followed by arbitrary
 		// data depending on which opcode it contains
-		assert!(self.data.len() >= sys::size_of::<fuse_in_header>());
+		assert!(self.data.len() >= mem::size_of::<fuse_in_header>());
 		let mut data = ArgumentIterator::new(self.data);
 		let header: &fuse_in_header = data.fetch();
 		let ch = se.ch;
@@ -341,7 +341,7 @@ impl Request {
 		do data.as_bytegroups |databytes| {
 			let datalen = databytes.iter().fold(0, |l, b| { l +  b.len()});
 			let outheader = fuse_out_header {
-				len: sys::size_of::<fuse_out_header>() as u32 + datalen as u32,
+				len: mem::size_of::<fuse_out_header>() as u32 + datalen as u32,
 				error: err as i32,
 				unique: inheader.unique,
 			};
diff --git a/src/sendable.rs b/src/sendable.rs
index d750b40..804581e 100644
--- a/src/sendable.rs
+++ b/src/sendable.rs
@@ -2,7 +2,7 @@
  * Helper to compose arbitrary data structures into packets of binary data.
  */
 
-use std::{cast, ptr, sys, vec};
+use std::{cast, ptr, mem, vec};
 use std::libc::{mode_t, off_t, S_IFMT};
 use native::{fuse_entry_out, fuse_attr_out, fuse_open_out};
 use native::{fuse_write_out, fuse_statfs_out, fuse_getxattr_out, fuse_lk_out};
@@ -17,7 +17,7 @@ pub trait Sendable {
 		// structs, i.e. fuse_*_out)
 		unsafe {
 			let ptr = ptr::to_unsafe_ptr(self);
-			let len = sys::size_of::<Self>();
+			let len = mem::size_of::<Self>();
 			do vec::raw::buf_as_slice(ptr as *u8, len) |bytes| {
 				f([bytes])
 			}
@@ -87,8 +87,8 @@ impl DirBuffer {
 	/// kernel uses these value to request more entries in further readdir
 	/// calls
 	pub fn fill (&mut self, ino: u64, off: off_t, mode: mode_t, name: &str) -> bool {
-		let entlen = sys::size_of::<fuse_dirent>() + name.len();
-		let entsize = (entlen + sys::size_of::<u64>() - 1) & !(sys::size_of::<u64>() - 1);	// 64bit align
+		let entlen = mem::size_of::<fuse_dirent>() + name.len();
+		let entsize = (entlen + mem::size_of::<u64>() - 1) & !(mem::size_of::<u64>() - 1);	// 64bit align
 		let padlen = entsize - entlen;
 		if self.data.len() + entsize > self.data.capacity() { return true; }
 		unsafe {
@@ -99,7 +99,7 @@ impl DirBuffer {
 				(*pdirent).off = off as u64;
 				(*pdirent).namelen = name.len() as u32;
 				(*pdirent).typ = (mode as u32 & S_IFMT as u32) >> 12;
-				let p = p.offset(sys::size_of_val(&*pdirent) as int);
+				let p = p.offset(mem::size_of_val(&*pdirent) as int);
 				do name.as_imm_buf |nameptr, namelen| {
 					ptr::copy_memory(p, nameptr, namelen);
 				}