diff --git a/include/fs.h b/include/fs.h
new file mode 100644
index 0000000..ba9f0cf
--- /dev/null
+++ b/include/fs.h
@@ -0,0 +1,130 @@
+#include "rawdisk.h"
+
+class SuperBlock{
+public:
+    static off_t getFreeListHead(){
+        char buffer[512] = {0};
+        rawdisk_read(0, buffer);
+        off_t t = 0;
+        for (int j = 0; j < 8; j++)
+            t = t | (((off_t)buffer[j])<<(8*j));
+        return t;
+    }
+
+    static void writeFreeListHead(){
+        char buffer[512] = {0};
+        for (int j = 0; j < 8; j++){
+            buffer[j] = t & (((off_t)1<<(8*j))-1);
+            t >>= 8;
+        }
+        rawdisk_write(0, buffer);
+    }
+};
+
+class INode{
+    // direct datablocks 
+    off_t blocks[48];
+    // indirect address
+    off_t single_indirect, double_indirect, triple_indirect;
+    // other 
+
+    off_t uid;
+    off_t gid;
+    off_t permissions;
+    off_t size;
+
+public:
+    void read_get_byte(off_t &t, int &current_pos, char *buffer){
+        t = 0;
+        for (int j = 0; j < 8; j++)
+            t = t | (((off_t)buffer[j+current_pos])<<(8*j));
+        current_pos += 8;
+    }
+
+    void inode_construct(off_t blockNumber){
+        char buffer[512] = {0};
+        rawdisk_read(blockNumber, buffer);
+        int current_pos = 0;
+        // initialize blocks
+        for (int i = 0; i < 48; i++){
+            read_get_byte(block[i], current_pos, buffer);
+        }
+        read_get_byte(single_indirect, current_pos, buffer);
+        read_get_byte(double_indirect, current_pos, buffer);
+        read_get_byte(triple_indirect, current_pos, buffer);
+        read_get_byte(uid, current_pos, buffer);
+        read_get_byte(gid, current_pos, buffer);
+        read_get_byte(permissions, current_pos, buffer);
+        read_get_byte(size, current_pos, buffer);
+    }
+
+    void write_get_byte(off_t t, int &current_pos, char *buffer){
+        for (int j = 0; j < 8; j++){
+            buffer[j+current_pos] = t & (((off_t)1<<(8*j))-1);
+            t >>= 8;
+        }
+        current_pos += 8;
+    }
+
+    void inode_save(off_t blockNumber){
+        char buffer[512] = {0};
+        int current_pos = 0;
+        for (int i = 0; i < 48; i++){
+            write_get_byte(block[i], current_pos, buffer);
+        }
+        write_get_byte(single_indirect, current_pos, buffer);
+        write_get_byte(double_indirect, current_pos, buffer);
+        write_get_byte(triple_indirect, current_pos, buffer);
+        write_get_byte(uid, current_pos, buffer);
+        write_get_byte(gid, current_pos, buffer);
+        write_get_byte(permissions, current_pos, buffer);
+        write_get_byte(size, current_pos, buffer);
+        rawdisk_write(bloackNumber, buffer);
+    }
+
+    // allowcate 1 datablock and add to the end of the file
+    off_t datablock_allocate(){
+        //do we need to check dynamic?
+        
+        //find a free data block
+        off_t freeListHead = SuperBlock::getFreeListHead();
+        for (freeListHead)
+
+        //add the data block to blocks, single, double, triple
+        
+        //return the block number
+
+    }
+
+    // deallocate 1 datablock from the end of the file
+    void datablock_deallocate(){
+
+    }
+}
+
+class INodeOperation{
+// free list head is at super block (0): first 8 bytes
+
+public:
+
+    // allocate an inode and return the number of the inode
+    // the i-th inode is in the i-th block
+    off_t inode_allocate(){
+        
+        //return inode number
+    }
+
+    // 
+    void inode_free(off_t iNodeNumber){
+
+    }
+
+    //ignore for now
+    void inode_read(){
+
+    }
+
+    void inode_write(){
+
+    }
+}
\ No newline at end of file