diff --git a/disk_file b/disk_file
new file mode 100644
index 0000000..550d34e
Binary files /dev/null and b/disk_file differ
diff --git a/src/simulator/disk.rs b/src/simulator/disk.rs
index 70c5b32..5499fa1 100644
--- a/src/simulator/disk.rs
+++ b/src/simulator/disk.rs
@@ -3,22 +3,86 @@ use std::fs::File;
 use std::io;
 use std::io::prelude::*;
 use std::io::SeekFrom;
+use std::os::unix::prelude::FileExt;
 
 pub const SECTORS_PER_TRACK: i32 = 32;
 pub const NUM_TRACKS: i32 = 64;
 pub const NUM_SECTORS: i32 = SECTORS_PER_TRACK * NUM_TRACKS;
-pub const SECTOR_SIZE: i32 = 4;
+pub const SECTOR_SIZE: i32 = 4;//4 octects ?
+
+
+pub const MAGIC_NUMBER : u32 = 0xABBACDDC; 
+//taille en octets, a confirmer
+pub const DISK_SIZE: i32 = 4 +  NUM_SECTORS*SECTOR_SIZE;//4 <=> sizeof(u32)
 
 pub struct Disk {
-    pub last_selector: i32,
-    pub active: bool,
+    pub last_sector: i32,//Secteur accédé lors de la précédente requête de lecture/ecriture
+    pub active: bool,//C'est notre lock -> Une seule requête de lecture/ecriture à la fois
+    pub disk_file : File //On simule le disque sur un fichier
+    //Manque une ref a une fonction type handler, fournie via constructeur dans Nachos
 }
 
 impl Disk {
     pub fn init_disk() -> Disk {
+
+        //see Rust File impl FileExt for File For UNIX mode
+        let mut magic_buff : [u8 ; 4] = [0u8 ; 4];
+        let mut readed_magic_number : u32;
+        let disk_file : File;
+
+        let result_open = File::options().
+                                read(true).
+                                write(true).
+                                open("disk_file");
+        
+        match result_open {
+
+            Err(e) => {
+                //On creer le fichier et on y écrit le magic number
+                let magic_to_write : [u8 ; 5] = [0xAB, 0xBA, 0xCD, 0xDC, 0];
+                println!("Error opening file : {}", e);
+
+                disk_file = File::options().
+                            read(true).
+                            write(true).
+                            create_new(true).
+                            open("disk_file").unwrap();
+
+                disk_file.write_at(&magic_to_write[..], 0);
+            }
+
+            Ok(f) => {
+                disk_file = f;
+            }
+        }
+
+        match disk_file.read_at(&mut magic_buff[..], 0) {
+
+            Ok(t) => {
+                println!("init_disk :: on a lu {} octets", t);
+                readed_magic_number = ((magic_buff[0] as u32) <<24)
+                                    + ((magic_buff[1] as u32) <<16)
+                                    + ((magic_buff[2] as u32) <<8)
+                                    + ((magic_buff[3] as u32) <<0);
+
+                if readed_magic_number != MAGIC_NUMBER {
+                    panic!("init_disk :: Did not recognize magic number at the beginning of disk_file,
+                    On a lu {:#08x}, Panic", readed_magic_number);
+                }
+                else {
+                    println!("init_disk :: on a lu le magic_number {:#08x}", readed_magic_number);
+                }
+            }
+
+            Err(e) => {
+                println!("init_disk :: Error reading file : {}", e);
+            }
+        }
+        
         Disk {
-            last_selector: 0,
+            last_sector: 0,
             active: false,
+            disk_file: disk_file
         }
     }
 
@@ -97,11 +161,29 @@ impl Disk {
 }
 
 
+pub fn stupid_fct(buf : &[u8]){
+
+    println!("Size of unknown sized parameter buffer : {}", buf.len());
+    for i in 0..buf.len() {
+        println!("buf[{}] = {}", i, buf[i]);
+    }
+}
+
 #[cfg(test)]
 mod test {
 
     use crate::Disk;
 
+    use super::stupid_fct;
+
+    #[test]
+    fn test_init_stupid_fct() {
+        let buffy: [u8 ; 6] = [1,2,3,4,5,6];
+        stupid_fct(&buffy);
+
+        //EN passant par une ref , on s'abstrait du besoin de connaitre la taille au moment de la compilation
+    }
+
     #[test]
     fn test_init_disk() {
         let disk = Disk::init_disk();
diff --git a/test/disk.txt b/test/disk.txt
index e69de29..8067c5c 100644
Binary files a/test/disk.txt and b/test/disk.txt differ