diff --git a/src/filesys/filehdr.rs b/src/filesys/filehdr.rs
index e6dcad9..920ae1a 100644
--- a/src/filesys/filehdr.rs
+++ b/src/filesys/filehdr.rs
@@ -20,6 +20,19 @@ pub struct FileHdr {
 
 impl FileHdr { 
 
+
+    pub fn init_file_hdr() -> FileHdr {
+        FileHdr { 
+            is_dir: 0, 
+            num_bytes: 0, 
+            num_sectors: 0, 
+            data_sectors: Vec::new(), 
+            num_header_sectors: 0, 
+            header_sectors: [0;MAX_HEADER_SECTORS as usize],
+        }
+    }
+
+
     pub fn allocate(&mut self, mut free_map: BitMap, file_size: i32) -> bool {
         self.num_bytes = file_size;
         if file_size > MAX_FILE_LENGTH {
@@ -87,6 +100,11 @@ impl FileHdr {
     //TODO: fetchFrom WriteBack
 
 
+
+
+
+
+
     pub fn byte_to_sector(&self,offset: i32) -> i32 {
         return self.data_sectors[ (offset / SECTOR_SIZE) as usize];
     }
diff --git a/src/utility/bitmap.rs b/src/utility/bitmap.rs
index a34e5b4..d66dd2e 100644
--- a/src/utility/bitmap.rs
+++ b/src/utility/bitmap.rs
@@ -4,6 +4,8 @@ pub const BITS_IN_WORD: usize = 32;
 use std::fs::File;
 use std::io::{Cursor, Write, Read};
 
+use crate::simulator::disk::SECTOR_SIZE;
+
 pub struct BitMap {
     num_bits: usize,
     num_words: usize,
@@ -12,16 +14,44 @@ pub struct BitMap {
 
 impl BitMap {
 
+    /// Initialize a bitmap with "nitems" bits, so that every bit is clear.
+    ///	it can be added somewhere on a list.
+    ///
+    /// ### Parameters
+    ///	- **nitems** is the number of bits in the bitmap.
+    ///----------------------------------------------------------------------
+    pub fn init_bitmap(&self, n_items: usize) -> BitMap {
+        let mut tmp: Vec<u32>;
+        BitMap{
+            num_bits: n_items,
+            num_words: (n_items + SECTOR_SIZE as usize -1) / SECTOR_SIZE as usize,
+            map: tmp,
+        };
+
+        *self
+    }
+
+    /// Set the "nth" bit in a bitmap.
+    /// ### Parameters
+    ///	- **which** is the number of the bit to be set.
     pub fn mark(&mut self, which: usize) {
         assert!(which >= 0 && which < self.num_bits);
         self.map[which / BITS_IN_WORD] |= 1 << (which % BITS_IN_WORD);
     }
 
+    /// return true if the "nth" bit is set.
+    /// 
+    /// ### Paramenters 
+    /// - **which** is the number of the bit to be tested.
     pub fn test(&self, which: usize) -> bool {
         assert!(which < self.num_bits);
         (self.map[which / BITS_IN_WORD] & (1 << (which % BITS_IN_WORD))) != 0
     }
 
+    /// Return the number of the first bit which is clear.
+    ///	As a side effect, set the bit (mark it as in use).
+    ///	(In other words, find and allocate a bit.)
+    /// If no bits are clear, return ERROR
     pub fn find(&mut self) -> i32 {
         for i in 0..self.num_bits {
             if !self.test(i) {
@@ -32,6 +62,9 @@ impl BitMap {
         -1
     }
 
+    /// Clear the "nth" bit in a bitmap.
+    /// ### Parameters
+    /// - **which** is the number of the bit to be cleared.
     pub fn clear(&mut self, which: usize) {
         assert!(which < self.num_bits, "index out of range");
 
@@ -40,6 +73,8 @@ impl BitMap {
         self.map[word_idx] &= !(1 << bit_idx);    
     }
 
+    /// Return the number of clear bits in the bitmap.
+    ///	(In other words, how many bits are unallocated?)
     pub fn num_clear(&self) -> i32 {
         let mut count = 0;
         for i in 0..self.num_bits {
@@ -50,6 +85,9 @@ impl BitMap {
         count
     }
 
+    /// Print the contents of the bitmap, for debugging.
+    /// Could be done in a number of ways, but we just print the #'s of
+    ///	all the bits that are set in the bitmap.
     pub fn print(&self) {
         println!("Bitmap set:");
         for i in 0..self.num_bits {
@@ -60,8 +98,10 @@ impl BitMap {
         println!();
     }
 
-
-
+    ///Initialize the contents of a bitmap from a Nachos file.
+    ///
+    /// ### Parameters
+    ///	- **file** is the place to read the bitmap from
     pub fn fetch_from(&mut self, file_path: &str) -> std::io::Result<&Vec<u32>> {
         // Ouvre le fichier en mode lecture seule
         let mut file = File::open(file_path)?;
@@ -83,6 +123,10 @@ impl BitMap {
         Ok(&self.map)
     }
 
+    /// Store the contents of a bitmap to a Nachos file.
+    ///
+    /// ### Paramenters
+    /// - **file** is the place to write the bitmap to
     pub fn write_back(&mut self, file_path: &str) -> std::io::Result<()> {
         // Encapsule le vecteur dans un std::io::Cursor pour l'utiliser comme un std::io::Write
         let mut cursor = Cursor::new(Vec::<u8>::new());
@@ -98,5 +142,4 @@ impl BitMap {
 
         Ok(())
     }
-
 }
\ No newline at end of file