diff --git a/include/fs.h b/include/fs.h
new file mode 100644
index 0000000..067d595
--- /dev/null
+++ b/include/fs.h
@@ -0,0 +1,464 @@
+#include "rawdisk.h"
+/*****************************************************
+30GB Disk low-level operation and data structure: spuerblock, inode, and buffer cache
+512 bytes sector for 1 block, 62914560 block(sector)
+4K bytes sector for 1 block,   7864320 block(sector)
+
+one inode equipped with one 512 bytes block
+
+*****************************************************/
+#define SECTOR_SIZE 512
+#define IO_BLOCK_SIZE 4096
+#define MAX_INODE 524288
+#define MAX_BLOCKNUM MAX_INODE*2 //62914560
+
+class SuperBlock{
+
+public:
+    SuperBlock(const char *directory){
+
+    }
+    ~SuperBlock(){
+
+    }
+    static u_int64_t getFreeListHead(RawDisk &disk){
+        char buffer[8] = {0};
+        disk.rawdisk_read(0, buffer, sizeof(buffer));
+        u_int64_t t = 0;
+        for (int j = 0; j < 8; j++)
+            t = t | (((u_int64_t)(unsigned char)buffer[j])<<(8*j));
+        return t;
+    }
+
+    static void writeFreeListHead(RawDisk &disk, u_int64_t t){
+        char buffer[8] = {0};
+        for (int j = 0; j < 8; j++){
+            buffer[j] = (t >> (8 * j)) & 0xFF;
+        }
+        disk.rawdisk_write(0, buffer, sizeof(buffer));
+    }
+
+    static u_int64_t getFreeINodeHead(RawDisk &disk){
+        char buffer[8] = {0};
+        disk.rawdisk_read(8, buffer, sizeof(buffer));
+        u_int64_t t = 0;
+        for (int j = 0; j < 8; j++)
+            t = t | (((u_int64_t)(unsigned char)buffer[j])<<(8*j));
+        return t;
+    }
+
+    static void writeFreeINodeHead(RawDisk &disk, u_int64_t t){
+        char buffer[8] = {0};
+        for (int j = 0; j < 8; j++){
+            buffer[j] = (t >> (8 * j)) & 0xFF;
+        }
+        disk.rawdisk_write(8, buffer, sizeof(buffer));
+    }
+};
+
+class INode{
+    // direct datablocks 
+    u_int64_t blocks[48];
+    // indirect address
+    u_int64_t single_indirect, double_indirect, triple_indirect;
+    // other 
+
+    u_int64_t uid;
+    u_int64_t gid;
+    u_int64_t permissions;
+    u_int64_t size;
+    u_int64_t block_number;
+
+public:
+    void read_get_byte(u_int64_t &t, int &current_pos, char *buffer){
+        t = 0;
+        for (int j = 0; j < 8; j++)
+            t = t | (((u_int64_t)(unsigned char)buffer[j+current_pos])<<(8*j));
+        current_pos += 8;
+    }
+
+    static u_int64_t read_byte_at(int current_pos, char *buffer){
+        u_int64_t t = 0;
+        for (int j = 0; j < 8; j++)
+            t = t | (((u_int64_t)(unsigned char)buffer[j+current_pos])<<(8*j));
+        return t;
+    }
+
+    void inode_construct(u_int64_t blockNumber, RawDisk &disk){
+        char buffer[SECTOR_SIZE] = {0};
+        disk.rawdisk_read(blockNumber*SECTOR_SIZE, buffer, sizeof(buffer));
+        block_number = blockNumber;
+        int current_pos = 0;
+        // initialize blocks
+        for (int i = 0; i < 48; i++){
+            read_get_byte(blocks[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(u_int64_t t, int &current_pos, char *buffer){
+        for (int j = 0; j < 8; j++){
+            buffer[j+current_pos] = t & (((u_int64_t)1<<(8))-1);
+            t >>= 8;
+        }
+        current_pos += 8;
+    }
+
+    static void write_byte_at(u_int64_t t, int current_pos, char *buffer){
+        for (int j = 0; j < 8; j++){
+            buffer[j+current_pos] = t & (((u_int64_t)1<<(8))-1);
+            t >>= 8;
+        }
+    }
+
+    void inode_save(RawDisk &disk){
+        char buffer[SECTOR_SIZE] = {0};
+        int current_pos = 0;
+        for (int i = 0; i < 48; i++){
+            write_get_byte(blocks[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);
+        disk.rawdisk_write(block_number*SECTOR_SIZE, buffer, sizeof(buffer));
+    }
+
+    u_int64_t datablock_allocate_in_list(RawDisk &disk){
+        //find a free data block
+        u_int64_t freeListHead = SuperBlock::getFreeListHead(disk);
+        /*
+        1. initialization
+        2. data block starting position
+        3. r/w between storage and rawdisk to maintain 
+        */
+        char buffer[IO_BLOCK_SIZE] = {0};
+        u_int64_t freeBlockNum = 0;
+        disk.rawdisk_read(freeListHead, buffer, sizeof(buffer));
+        for (int i = 8; i < 264; i++){
+            if((i < 263 && buffer[i] != -1) || (i == 263 && buffer[i] != 127)){
+                int j = 0;
+                for (j = 0; j < 8; j++){
+                    if ((buffer[i]&(1<<j)) == 0){
+                        buffer[i] |= (1<<j);
+                        break;
+                    }
+                }
+                if (j < 8){
+                    freeBlockNum = freeListHead + ((i-8)*8 + j + 1)*IO_BLOCK_SIZE;
+                    break;
+                }
+            }
+        }
+        disk.rawdisk_write(freeListHead, buffer, sizeof(buffer));
+        bool notFull = false;
+        for (int i = 8; i < 264; i++){
+            if((i < 263 && buffer[i] != -1) || (i == 263 && buffer[i] != 127)){
+                notFull = true;
+                break;
+            }
+        }
+        if (!notFull){
+            printf("HEADER REMOVAL DETECTED %llu %llu\n", freeListHead, freeBlockNum);
+            u_int64_t next_header = read_byte_at(0, buffer);
+            SuperBlock::writeFreeListHead(disk, next_header);
+        }
+        return freeBlockNum;
+    }
+
+    bool allo_single_indirect(RawDisk &disk, u_int64_t &single_i, u_int64_t freeBlockNum) {
+        if (single_i == 0){
+            single_i = datablock_allocate_in_list(disk);
+        }
+        bool inSingle = false;
+        char buffer[IO_BLOCK_SIZE] = {0};
+        disk.rawdisk_read(single_i, buffer, sizeof(buffer));
+        for (int i = 0; i < IO_BLOCK_SIZE; i+=8){
+            u_int64_t addr = read_byte_at(i, buffer);
+            if(addr == 0){
+                inSingle = true;
+                write_byte_at(freeBlockNum, i, buffer);
+                disk.rawdisk_write(single_i, buffer, sizeof(buffer));
+                break;
+            }
+        }
+        return inSingle;
+    }
+
+    bool allo_double_indirect(RawDisk &disk, u_int64_t &double_i, u_int64_t freeBlockNum) {
+        if (double_i == 0){
+            double_i = datablock_allocate_in_list(disk);
+        }
+        bool inDouble = false;
+        char buffer[IO_BLOCK_SIZE] = {0};
+        disk.rawdisk_read(double_i, buffer, sizeof(buffer));
+        for (int i = 0; i < IO_BLOCK_SIZE; i+=8){
+            u_int64_t addr = read_byte_at(i, buffer);
+            bool flag = allo_single_indirect(disk, addr, freeBlockNum);
+            if (flag){
+                write_byte_at(addr, i, buffer);
+                disk.rawdisk_write(double_i, buffer, sizeof(buffer));
+                inDouble = true;
+                break;
+            }
+        } 
+        return inDouble;
+    }
+
+    bool allo_triple_indirect(RawDisk &disk, u_int64_t &triple_i, u_int64_t freeBlockNum) {
+        if (triple_i == 0){
+            triple_i = datablock_allocate_in_list(disk);
+        }
+        bool inTriple = false;
+        char buffer[IO_BLOCK_SIZE] = {0};
+        disk.rawdisk_read(triple_i, buffer, sizeof(buffer));
+        for (int i = 0; i < IO_BLOCK_SIZE; i+=8){
+            u_int64_t addr = read_byte_at(i, buffer);
+            bool flag = allo_double_indirect(disk, addr, freeBlockNum);
+            if (flag){
+                write_byte_at(addr, i, buffer);
+                disk.rawdisk_write(triple_i, buffer, sizeof(buffer));
+                inTriple = true;
+                break;
+            }
+        }
+        return inTriple;
+    }
+    
+    
+    // allowcate 1 datablock and add to the end of the file
+    u_int64_t datablock_allocate(RawDisk &disk){
+        //do we need to check dynamic?
+
+        //add the data block to blocks, single, double, triple
+        u_int64_t freeBlockNum = datablock_allocate_in_list(disk);
+        bool inBlocks = false;
+        for (int i = 0; i < 48; i++)
+            if(blocks[i] == 0){
+                inBlocks = true;
+                blocks[i] = freeBlockNum;
+                break;
+            }
+        if(!inBlocks){
+            bool inSingle = allo_single_indirect(disk, single_indirect, freeBlockNum);
+            if (!inSingle){
+                bool inDouble = allo_double_indirect(disk, double_indirect, freeBlockNum);
+                if (!inDouble){
+                    bool inTriple = allo_triple_indirect(disk, triple_indirect, freeBlockNum);
+                    // wait to deal with too big files
+                }
+            }      
+        }
+        
+        //return the block number
+        inode_save(disk);
+        return freeBlockNum;
+    }
+
+    void datablock_deallocate_in_list(u_int64_t freeBlockNum, RawDisk &disk) {
+        // find the related 2048block head
+        u_int64_t freeBlockHead = ((freeBlockNum/SECTOR_SIZE-MAX_INODE)/(8*2048)*(8*2048)+MAX_INODE)*SECTOR_SIZE;
+
+        // mark it alive in its bitmap
+        char buffer[IO_BLOCK_SIZE] = {0};
+        bool notEmpty = false;
+        disk.rawdisk_read(freeBlockHead, buffer, sizeof(buffer));
+        for (int i = 8; i < 264; i++){
+            if(buffer[i] != 0){
+                notEmpty = true;
+            }
+        }
+        u_int64_t inBlockPos = (freeBlockNum-freeBlockHead)/IO_BLOCK_SIZE-1;
+        buffer[8+inBlockPos/8] &= (-1)^(1<<(inBlockPos%8));
+    
+        // if its bitmap was 0, add it back to the list head
+        if(!notEmpty){
+            u_int64_t freeListHead = SuperBlock::getFreeListHead(disk);
+            write_byte_at(freeListHead, 0, buffer);
+            SuperBlock::writeFreeListHead(disk, freeBlockHead);
+        }
+        disk.rawdisk_write(freeBlockHead, buffer, sizeof(buffer));
+    }
+
+    u_int64_t deallo_single_indirect(RawDisk &disk, u_int64_t &single_i){
+        if (single_i == 0){
+            return 0;
+        }
+        u_int64_t freeBlockNum = 0;
+        char buffer[IO_BLOCK_SIZE] = {0};
+        int delpoint = -1;
+        disk.rawdisk_read(single_i, buffer, sizeof(buffer));
+        for (int i=4088; i >= 0; i--){
+            u_int64_t addr = read_byte_at(i, buffer);
+            if(addr != 0){
+                freeBlockNum = addr;
+                addr = 0;
+                write_byte_at(addr, i, buffer);
+                delpoint = i;
+                break;
+            }
+        }
+        disk.rawdisk_write(single_i, buffer, sizeof(buffer));
+        u_int64_t addr = read_byte_at(0, buffer);
+        if (delpoint == 0 && addr == 0){
+            datablock_deallocate_in_list(single_i, disk);
+            single_i = 0;
+        }
+        return freeBlockNum;
+    }
+
+    bool deallo_double_indirect(RawDisk &disk, u_int64_t &double_i){
+        if (double_i == 0){
+            return false;
+        }
+        u_int64_t freeBlockNum = 0;
+        char buffer[IO_BLOCK_SIZE] = {0};
+        int delpoint = -1;
+        disk.rawdisk_read(double_i, buffer, sizeof(buffer));
+        for (int i=4088; i >= 0; i-=8){
+            u_int64_t addr = read_byte_at(i, buffer);
+            u_int64_t inSingle = deallo_single_indirect(disk, addr);
+            if (inSingle){
+                freeBlockNum = inSingle;
+                write_byte_at(addr, i, buffer);
+                delpoint = i;
+                break;
+            }
+        }
+        disk.rawdisk_write(double_i, buffer, sizeof(buffer));
+        u_int64_t addr = read_byte_at(0, buffer);
+        if (delpoint == 0 && addr == 0){
+            datablock_deallocate_in_list(double_i, disk);
+            double_i = 0;
+        }
+        return freeBlockNum;
+    }
+
+    bool deallo_triple_indirect(RawDisk &disk, u_int64_t &triple_i){
+        if (triple_i == 0){
+            return false;
+        }
+        u_int64_t freeBlockNum = 0;
+        char buffer[IO_BLOCK_SIZE] = {0};
+        int delpoint = -1;
+        disk.rawdisk_read(triple_i, buffer, sizeof(buffer));
+        for (int i=4088; i >= 0; i-=8){
+            u_int64_t addr = read_byte_at(i, buffer);
+            u_int64_t inDouble = deallo_double_indirect(disk, addr);
+            if (inDouble){
+                freeBlockNum = inDouble;
+                write_byte_at(addr, i, buffer);
+                delpoint = i;
+                break;
+            }
+        }
+        disk.rawdisk_write(triple_i, buffer, sizeof(buffer));
+        u_int64_t addr = read_byte_at(0, buffer);
+        if (delpoint == 0 && addr == 0){
+            datablock_deallocate_in_list(triple_i, disk);
+            triple_i = 0;
+        }
+        return freeBlockNum;
+    }
+
+    // deallocate 1 datablock from the end of the file
+    u_int64_t datablock_deallocate(RawDisk &disk){
+        // find the last datablock and remove it from inode (triple->direct)
+        u_int64_t freeBlockNum = 0;
+        freeBlockNum = deallo_triple_indirect(disk, triple_indirect);
+        if(!freeBlockNum){
+            freeBlockNum = deallo_double_indirect(disk, double_indirect);
+            if(!freeBlockNum){
+                freeBlockNum = deallo_single_indirect(disk, single_indirect);
+                if(!freeBlockNum){
+                    for(int i = 47; i>=0; i--)
+                        if(blocks[i] != 0){
+                            freeBlockNum = blocks[i];
+                            blocks[i] = 0;
+                            break;
+                        }
+                    // deal with empty
+                }
+            }
+        }
+
+        // add it back to freeBlocklist
+        datablock_deallocate_in_list(freeBlockNum, disk);
+        inode_save(disk);
+        return freeBlockNum;
+    }
+};
+
+class INodeOperation{
+// free list head is at super block (0): first 8 bytes
+
+public:
+    //initialization of the rawdisk
+    void initialize(RawDisk &disk){
+        // initialize Inode list head
+        SuperBlock::writeFreeINodeHead(disk, 1);
+        for (u_int64_t i = 1; i < MAX_INODE; i++){
+            char buffer[SECTOR_SIZE] = {0};
+            u_int64_t t = i + 1;
+            if (t < MAX_INODE){
+                for (int j = 0; j < 8; j++){
+                    buffer[j] = (t >> (8 * j)) & 0xFF;
+                }
+            }
+            disk.rawdisk_write(i*SECTOR_SIZE, buffer, sizeof(buffer));
+        }
+        SuperBlock::writeFreeListHead(disk, MAX_INODE*SECTOR_SIZE); // maximum inode number 2^19 0x80000
+        //Have tested this initialize function but MAX_BLOCK too much, MAX_INODE*2 works
+        for (u_int64_t i = MAX_INODE; i < MAX_BLOCKNUM-4096; i += 2048*8){
+            char buffer[IO_BLOCK_SIZE] = {0};
+            u_int64_t t = (i + 2048*8)*SECTOR_SIZE;
+            //t is address, storing in to buffer
+            for (int j = 0; j < 8; j++){
+                buffer[j] = (t >> (8 * j)) & 0xFF;
+            }
+            disk.rawdisk_write(i*SECTOR_SIZE, buffer, sizeof(buffer));
+        }
+    }
+
+    // allocate an inode from free inode list head and return the number of the inode
+    // the i-th inode is in the i-th block
+    u_int64_t inode_allocate(RawDisk &disk){
+        u_int64_t freeINodeHead = SuperBlock::getFreeINodeHead(disk);
+        char buffer[SECTOR_SIZE] = {0};
+        disk.rawdisk_read(freeINodeHead*SECTOR_SIZE, buffer, sizeof(buffer));
+        u_int64_t newINodeHead = INode::read_byte_at(0, buffer);
+        // deal with no more INode
+        SuperBlock::writeFreeINodeHead(disk, newINodeHead);
+        //to do: initialize the INode on disk at freeINodeHead
+
+        //return inode number
+        return freeINodeHead;
+    }
+
+    // free the inode and add it to the free inode list head
+    void inode_free(RawDisk &disk, u_int64_t INodeNumber){
+        u_int64_t freeINodeHead = SuperBlock::getFreeINodeHead(disk);
+        char buffer[SECTOR_SIZE] = {0};
+        INode::write_byte_at(freeINodeHead, 0, buffer);
+        disk.rawdisk_write(INodeNumber*SECTOR_SIZE, buffer, sizeof(buffer));
+        SuperBlock::writeFreeINodeHead(disk, INodeNumber);
+    }
+
+    //ignore for now
+    void inode_read(){
+
+    }
+
+    void inode_write(){
+
+    }
+};
\ No newline at end of file
diff --git a/include/rawdisk.h b/include/rawdisk.h
index efd45ed..4cccf70 100644
--- a/include/rawdisk.h
+++ b/include/rawdisk.h
@@ -10,8 +10,8 @@ class RawDisk{
 
     int fd;
     const char* dir;
-    off_t numSectors;
-    off_t diskSize;
+    u_int64_t numSectors;
+    u_int64_t diskSize;
 
 public:
     RawDisk(const char *directory) : fd(-1), dir(nullptr), numSectors(0), diskSize(0) {
@@ -48,8 +48,8 @@ public:
         }
     }
 
-    int rawdisk_read(off_t offset, char *buffer, size_t length) {
-        if (lseek(fd, offset, SEEK_SET) == (off_t)-1) {
+    int rawdisk_read(u_int64_t offset, char *buffer, size_t length) {
+        if (lseek(fd, offset, SEEK_SET) == (u_int64_t)-1) {
             perror("Error seeking to offset");
             return -1;
         }
@@ -64,8 +64,8 @@ public:
     }
 
     // Write a specified number of bytes at a given byte offset
-    int rawdisk_write(off_t offset, char *buffer, size_t length) {
-        if (lseek(fd, offset, SEEK_SET) == (off_t)-1) {
+    int rawdisk_write(u_int64_t offset, char *buffer, size_t length) {
+        if (lseek(fd, offset, SEEK_SET) == (u_int64_t)-1) {
             perror("Error seeking to offset");
             return -1;
         }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 4ff961f..b946592 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,4 +1,5 @@
 set(TARGET_LAYER0 test_layer0)
+set(TARGET_LAYER1_API test_layer1_API)
 set(DIR_PLACE /dev/vdb)
 
 # add test sources here ... 
@@ -6,6 +7,11 @@ add_executable(${TARGET_LAYER0}
     # add need lib and source code here
     layer0.cpp
 )
+add_executable(${TARGET_LAYER1_API}
+    # add need lib and source code here
+    layer1_API.cpp
+)
 
 # add test to activate ctest -VV
-add_test(NAME ${TARGET_LAYER0} COMMAND sudo ./${TARGET_LAYER0} ${DIR_PLACE})
\ No newline at end of file
+add_test(NAME ${TARGET_LAYER0} COMMAND sudo ./${TARGET_LAYER0} ${DIR_PLACE})
+add_test(NAME ${TARGET_LAYER1_API} COMMAND sudo ./${TARGET_LAYER1_API} ${DIR_PLACE})
\ No newline at end of file
diff --git a/test/layer0.cpp b/test/layer0.cpp
index be5d998..8cc358a 100644
--- a/test/layer0.cpp
+++ b/test/layer0.cpp
@@ -14,11 +14,11 @@ int main(int argc, char *argv[]) {
     //printf("dir %s, numSectors %lld, diskSize %lld \n", H->dir, H->numSectors, H->diskSize);
 
     //use number to substitute H->getnumSector(), getnumSectors() are not yest implemented
-    for(off_t i = 0; i < 10; i++) {
+    for(u_int64_t i = 0; i < 10; i++) {
         H->rawdisk_write(i*512, buf, strlen(buf));//Change write_API
     }
     //use number to substitute H->getnumSector(), getnumSectors() are not yest implemented
-    for(off_t i = 0; i < 10; i++) {
+    for(u_int64_t i = 0; i < 10; i++) {
         H->rawdisk_read(i*512, readBuffer, sizeof(readBuffer));//Change read_API
         assert(strncmp(readBuffer, buf, strlen(buf)) == 0);
     }
diff --git a/test/layer1_API.cpp b/test/layer1_API.cpp
new file mode 100644
index 0000000..0c63001
--- /dev/null
+++ b/test/layer1_API.cpp
@@ -0,0 +1,118 @@
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include "fs.h"
+#include <inttypes.h>
+
+int main(int argc, char *argv[]) {
+    const char* d = (argc < 2) ? "/dev/vdc" : argv[1];
+    
+    RawDisk *H = new RawDisk(d);
+
+    printf("test inode\n");
+    INodeOperation inop;
+    inop.initialize(*H);//for inode initialization and datablock initialization
+    char buffer[8] = {0};
+    /**************************test inode Initialization***************************/
+    //test the begining of inode 1th
+    H->rawdisk_read((1) * SECTOR_SIZE, buffer, sizeof(buffer));
+    u_int64_t t = 0;
+    for (int j = 0; j < 8; j++) 
+        t |= ((u_int64_t)(unsigned char)buffer[j]) << (8 * j);
+
+    assert(t == 2);//the first 1th unused inode will store the next unused inode 2th 
+    //test the number before end of inode 524286th
+    H->rawdisk_read((MAX_INODE - 2) * SECTOR_SIZE, buffer, sizeof(buffer));
+    t = 0;
+    for (int j = 0; j < 8; j++) 
+        t |= ((u_int64_t)(unsigned char)buffer[j]) << (8 * j);
+    
+    assert(t == MAX_INODE - 1);//store the maximun th inode
+    //test the end of inode 524287th
+    H->rawdisk_read((MAX_INODE - 1) * SECTOR_SIZE, buffer, sizeof(buffer));
+    t = 0;
+    for (int j = 0; j < 8; j++) 
+        t |= ((u_int64_t)(unsigned char)buffer[j]) << (8 * j);
+
+    assert(t == 0);//the end of inode(524287th inode) do not have the next inode address
+    /**************************test datablock Initialization***************************/
+    //we separate 2048 4kB I/O block(1+2047) as a group and the first I/O block will manage the following 2047 I/O block usage.
+    //the first 8 bytes(0~7) in first I/O block store the address of next first I/O block, the following 256(8~263) bytes record 2047 I/O block usage.
+    //test the begining of free datablock
+    H->rawdisk_read((MAX_INODE) * SECTOR_SIZE, buffer, sizeof(buffer));//the begining of free datablock will store from address (MAX_INODE) * SECTOR_SIZE
+    t = 0;
+    for (int j = 0; j < 8; j++) 
+        t |= ((u_int64_t)(unsigned char)buffer[j]) << (8 * j);
+
+    assert(t == (MAX_INODE+2048*8)*SECTOR_SIZE);//the first 8 bytes of 4k I/O block will store the next address(after 2048*4k I/O block)
+    //test the end of the datablock
+    H->rawdisk_read((MAX_BLOCKNUM - 2048*8) * SECTOR_SIZE, buffer, sizeof(buffer));
+    t = 0;
+    for (int j = 0; j < 8; j++) 
+        t |= ((u_int64_t)(unsigned char)buffer[j]) << (8 * j);
+
+    assert(t == (MAX_BLOCKNUM)*SECTOR_SIZE);
+
+    /***************************test inode de/allocation**********************************/
+    //when requesting an inode, the inode_allocation will give you the inode number, we use inode_list to store the sequence allocate inode
+    //arrary version
+    int inode_list[20] = {0};
+    int record_free[10] = {0};//should do a pop up structure to record the free inode 
+    int rec = 9;
+    //printf("Allocate 20 inode num:{");
+    for(int i=0;i<20;i++){
+        inode_list[i] = inop.inode_allocate(*H);
+        assert(inode_list[i] == i+1);
+        //printf(" %d", inode_list[i]);
+    }
+    //printf("}\n");
+    for(int i=10;i<20;i++){
+        inop.inode_free(*H,inode_list[i]);//free the 10 element from inode_list[10]
+        record_free[i-10] = inode_list[i];
+    }
+    //allocate again the last 10
+    printf("Allocate again: inode num:{");
+    for(int i=10;i<20;i++){
+        inode_list[i] = inop.inode_allocate(*H);
+        //printf("inode %d, rec_f %d\n,", inode_list[i],record_free[rec]);
+        assert(inode_list[i] == record_free[rec]);
+        rec--;
+    }
+    printf("}\n");
+    /***************************test direct blocks[48] de/allocation**********************************/
+    //after free the datablock, the program will find the first smallest address of datablock to give to the inode
+    //should test random resize each node, but should use datablock_free data structure to record
+    INode inode_inside[10];
+    u_int64_t rec_datablock_free[10][3] = {0};//array version
+    for(int i=0;i<10;i++){
+        inode_inside[i].inode_construct(inode_list[i],*H);
+        //printf("%dth data block starting addres: ", i);
+        for(int j=0;j<6;j++){
+            inode_inside[i].datablock_allocate(*H);
+            //printf("%d," ,inode_inside[i].datablock_allocate(*H));
+        }
+        //printf("\n");
+    }
+    for(int i=0;i<10;i++){
+        //printf("%dth data block free addres: ", i);
+        for(int j = 2;j >=0;j--){
+            rec_datablock_free[i][j] = inode_inside[i].datablock_deallocate(*H);
+            //printf("", rec_datablock_free[i][j]);
+        }
+        //printf("\n");
+    }
+
+    for(int i=0;i<10;i++){
+        //printf("%dth data block allocate again addres: ", i);
+        for(int j=0;j<3;j++){
+            assert(inode_inside[i].datablock_allocate(*H) == rec_datablock_free[i][j]);
+            //printf("%d," ,inode_inside[i].datablock_allocate(*H));
+        }
+        //printf("\n");
+    }
+
+    //printf("}\n");
+    delete H;  // Delete the RawDisk object
+
+    return 0;
+}