diff --git a/src/fd/mod.rs b/src/fd/mod.rs
index e2a4eff..f983188 100644
--- a/src/fd/mod.rs
+++ b/src/fd/mod.rs
@@ -6,7 +6,7 @@ use async_trait::async_trait;
 use core::cell::RefCell;
 use lazy_static::lazy_static;
 
-pub type FDt = Arc<AsyncMutex<dyn FileDescriptor>>;
+pub type FDt = Arc<RefCell<dyn FileDescriptor>>;
 
 lazy_static! {
     pub static ref FD_TABLE: AsyncMutex<FDTable> = {
diff --git a/src/fs/iso/fd.rs b/src/fs/iso/fd.rs
index 95b8e04..ee9954a 100644
--- a/src/fs/iso/fd.rs
+++ b/src/fs/iso/fd.rs
@@ -12,7 +12,7 @@ pub struct IsoFD {
 
 impl IsoFD {
     pub fn new() -> FDt {
-        Arc::new(AsyncMutex::new(IsoFD {
+        Arc::new(RefCell::new(IsoFD {
             fd: FDId::new(),
         }))
     }
diff --git a/src/fs/iso/mod.rs b/src/fs/iso/mod.rs
index 81297b3..610c5a7 100644
--- a/src/fs/iso/mod.rs
+++ b/src/fs/iso/mod.rs
@@ -13,12 +13,12 @@ use fd::IsoFD;
 use alloc::{sync::Arc, boxed::Box};
 use async_trait::async_trait;
 
-struct IsoFS {
+pub struct IsoFS {
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl FileSystem for IsoFS {
-    async fn open(&mut self, path: &str, flags: u32) -> Option<FDt> {
+    async fn open(path: &str, flags: u32) -> Option<FDt> {
         if flags != crate::syscalls::io::O_RDONLY {
             return None;
         }
diff --git a/src/fs/mod.rs b/src/fs/mod.rs
index 76d187f..7631314 100644
--- a/src/fs/mod.rs
+++ b/src/fs/mod.rs
@@ -5,7 +5,7 @@ use crate::fd::FDt;
 use alloc::{sync::Arc, boxed::Box};
 use async_trait::async_trait;
 
-#[async_trait]
+#[async_trait(?Send)]
 pub trait FileSystem {
-    async fn open(&mut self, path: &str, flags: u32) -> Option<FDt>;
+    async fn open(path: &str, flags: u32) -> Option<FDt>;
 }
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 55bb752..240a2ec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -20,6 +20,7 @@ use core::panic::PanicInfo;
 use drivers::vga::{self, Color, ColorCode};
 use multiboot2::BootInformation;
 use task::{executor::Executor, keyboard, Task};
+use crate::fs::FileSystem;
 
 #[alloc_error_handler]
 fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
@@ -65,6 +66,6 @@ pub extern "C" fn julios_main(multiboot_info_addr: usize) -> ! {
 
 
 async fn get_file() {
-    let fd = fs::iso::open("test", syscalls::io::O_RDONLY).await.unwrap();
+    let fd = fs::iso::IsoFS::open("test", syscalls::io::O_RDONLY).await.unwrap();
     fd.borrow_mut().read(&[], 0).await;
 }
\ No newline at end of file