diff --git a/src/lib.rs b/src/lib.rs
index ce007b64..d04591e6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,13 +8,18 @@ use core::ffi::{c_char, c_void};
 extern crate yggdrasil_abi as abi;
 
 pub use abi::error::Error;
-pub use abi::io::{OpenFlags, RawFd};
 pub use abi::path;
 pub mod alloc;
 pub mod netc;
 pub mod sys;
 pub mod time;
 
+pub mod io {
+    //! I/O data structures
+
+    pub use abi::io::{MountOptions, OpenFlags, RawFd, UnmountOptions};
+}
+
 /// Type alias for a raw file descriptor
 
 #[no_mangle]
@@ -26,9 +31,7 @@ unsafe extern "C" fn memcmp(_p0: *const c_void, _p1: *const c_void, _len: usize)
 unsafe extern "C" fn memcpy(p0: *mut c_void, p1: *const c_void, len: usize) -> *mut c_void {
     let mut offset = 0;
     while offset < len {
-        (p0 as *mut u8)
-            .add(offset)
-            .write((p1 as *mut u8).add(offset).read());
+        (p0 as *mut u8).add(offset).write((p1 as *mut u8).add(offset).read());
         offset += 1;
     }
     p0
diff --git a/src/sys.rs b/src/sys.rs
index c3f38ce0..558eb186 100644
--- a/src/sys.rs
+++ b/src/sys.rs
@@ -2,8 +2,8 @@
 use core::time::Duration;
 
 use abi::{
-    error::{Error, FromSyscallResult},
-    io::{OpenFlags, RawFd},
+    error::{Error, SyscallResult},
+    io::{MountOptions, OpenFlags, RawFd, UnmountOptions},
     syscall::SyscallFunction,
 };
 
@@ -64,9 +64,7 @@ macro_rules! argp {
     };
 }
 
-/// [SyscallFunction::DebugTrace] call.
-///
-/// * msg: message to print to the debug trace log.
+/// System call: print a message to kernel's debug trace output.
 ///
 /// # Safety
 ///
@@ -75,7 +73,7 @@ pub unsafe fn debug_trace(msg: &str) {
     syscall!(SyscallFunction::DebugTrace, argp!(msg.as_ptr()), argn!(msg.len()));
 }
 
-/// [SyscallFunction::MapMemory] call.
+/// System call: map a virtual memory region into the process's address space.
 ///
 /// * virt: hint to the memory manager. Mapping is not guaranteed to be placed at the specific
 /// address, but the kernel will at least try.
@@ -89,7 +87,7 @@ pub unsafe fn map_memory(virt: Option<usize>, len: usize) -> Result<usize, Error
     usize::from_syscall_result(syscall!(SyscallFunction::MapMemory, argn!(virt), argn!(len)))
 }
 
-/// [SyscallFunction::UnmapMemory] call.
+/// System call: release a virtual memory region.
 ///
 /// * virt: address of the region to unmap.
 /// * len: length of the region to unmap.
@@ -101,7 +99,7 @@ pub unsafe fn unmap_memory(virt: usize, len: usize) -> Result<(), Error> {
     <()>::from_syscall_result(syscall!(SyscallFunction::UnmapMemory, argn!(virt), argn!(len)))
 }
 
-/// [SyscallFunction::Nanosleep] call.
+/// System call: suspend caller task for some time.
 ///
 /// * duration: amount of time to sleep.
 ///
@@ -114,7 +112,7 @@ pub unsafe fn nanosleep(duration: Duration) {
     syscall!(SyscallFunction::Nanosleep, argn!(seconds), argn!(nanos));
 }
 
-/// [SyscallFunction::Exit] call.
+/// System call: terminate current process.
 ///
 /// * code: process termination status code.
 ///
@@ -126,7 +124,7 @@ pub unsafe fn exit(code: i32) -> ! {
     panic!();
 }
 
-/// [SyscallFunction::Write] call.
+/// System call: write `data` to a file descriptor.
 ///
 /// * fd: file descriptor to write to.
 /// * data: data to write to the file.
@@ -143,24 +141,24 @@ pub unsafe fn write(fd: RawFd, data: &[u8]) -> Result<usize, Error> {
     ))
 }
 
-/// [SyscallFunction::Read] call.
+/// System call: read data from a file descriptor into `buf`.
 ///
 /// * fd: file descriptor to read from.
-/// * data: buffer to store the read data.
+/// * buf: buffer to store the read data.
 ///
 /// # Safety
 ///
 /// Unsafe: direct system call.
-pub unsafe fn read(fd: RawFd, data: &mut [u8]) -> Result<usize, Error> {
+pub unsafe fn read(fd: RawFd, buf: &mut [u8]) -> Result<usize, Error> {
     usize::from_syscall_result(syscall!(
         SyscallFunction::Read,
         argn!(fd.0),
-        argp!(data.as_ptr()),
-        argn!(data.len())
+        argp!(buf.as_ptr()),
+        argn!(buf.len())
     ))
 }
 
-/// [SyscallFunction::Open] call.
+/// System call: open a file with given options.
 ///
 /// * path: path of the file to open.
 /// * opts: flags and mode to open the file with.
@@ -177,7 +175,7 @@ pub unsafe fn open(path: &str, opts: OpenFlags) -> Result<RawFd, Error> {
     ))
 }
 
-/// [SyscallFunction::Close] call.
+/// System call: close a file descriptor.
 ///
 /// * fd: file descriptor to close.
 ///
@@ -187,3 +185,25 @@ pub unsafe fn open(path: &str, opts: OpenFlags) -> Result<RawFd, Error> {
 pub unsafe fn close(fd: RawFd) -> Result<(), Error> {
     <()>::from_syscall_result(syscall!(SyscallFunction::Close, argn!(fd.0)))
 }
+
+/// System call: mount a filesystem at desired mountpoint.
+///
+/// * options: see [MountOptions].
+///
+/// # Safety
+///
+/// Unsafe: direct system call.
+pub unsafe fn mount(options: &MountOptions) -> Result<(), Error> {
+    <()>::from_syscall_result(syscall!(SyscallFunction::Mount, argp!(options as *const _)))
+}
+
+/// System call: unmount a filesystem from specified mountpoint.
+///
+/// * options: see [UnmountOptions].
+///
+/// # Safety
+///
+/// Unsafe: direct system call.
+pub unsafe fn unmount(options: &UnmountOptions) -> Result<(), Error> {
+    <()>::from_syscall_result(syscall!(SyscallFunction::Unmount, argp!(options as *const _)))
+}