file management system

FILE MANAGEMENT SYSTEM

Group MembersRAMOLY NathanHEMMI FlorentAZANGUE RoméoCHOUIKH Jaouher JRIDI BayremNINTIDEM Estelle Olivia

Supervisor M. TIMSIT Claude

Academic year 2011-2012

INTRODUCTIONPLAN

CONCLUSION

I. MATERIAL AND DIFFERENTS STAGES

II. METHODS AND SYSTEM DESIGN

III. PROBLEMS AND SOLUTIONS

IV. DEMONSTRATION

Nathan RAMOLY, Florent HEMMI, Roméo AZANGUE, Jaouher CHOUIKH, Bayrem JRIDI, Estelle NINTIDEM

RAMOLY Nathan, HEMMI Florent, AZANGUE Roméo, CHOUIKH Jaouher, JRIDI Bayrem, NINTIDEM Estelle

INTRODUCTION

The file management system

Software that manages data files

Create, enter, change and query files

EXT2, HFS PLUS , FAT


INTRODUCTION

Requirements

Functional Requirements• Management module• Execution module• Documentation module

Non-Functional Requirements• Convenient GUI• Clear errors messages


INTRODUCTION

Use Case Diagram



Material• Software

o Code blocks o QT

• Turtoise SVN (Subversion)

• Libraries

o Standard libraries



Differents Stages

• The Theory • Realisation

• Debug



The Theory

Simulation of the disk



Handling of the disk

disk_access disk_ptr disk_set_block

disk_get_block load_disk_hard_dri

ve save_disk_hard_dri

ve…



Bitmaps

Root

/

Boot block

Inode

bitmap

Block

bitmap

Inodes Blocks

Bitmap



Bitmaps

Inodes

0, 1, 2, 3

Inodes

4, 5, 6, 7

Inodes

8,9,10, 11

Inode bitmap

0 1 0 0 0 0 0 0



Bitmaps

Data Block

0, 1, 2, 3

Data Block

4, 5, 6, 7

Data Block

8,9,10, 11

Block bitmap

0 1 0 0 0 0 0 0



Bitmaps Bitmap Inode

int8_t bitmap_inode_init() int8_t bitmap_inode_get_status(int numInode) int8_t bitmap_inode_set_status(int numInode, int

status) int32_t bitmap_first_free_inode() int32_t bitmap_nb_free_inode()



Bitmaps Bitmap Bloc

int8_t bitmap_block_init(). int8_t bitmap_block_get_status(int nBlock) int8_t bitmap_block_set_status(int nBlock, int

status) int32_t bitmap_first_free_block() int32_t bitmap_nb_free_block() int32_t bitmap_nb_occupied_block()



Inodes• The structure

o Size (in bytes)o The last access timeo Type (file or folder)o 10 addresses blockso An address for the single

indirection blocko An address for the double

indirection block



Inodes• Indirections



Inodes• Indirections 1 block = N bytes 10 blocks: 10*N bytes Single indirection: N²/4 Double indirection: N3/16 Total: [10 + N/4 + (N/4)²]*N



Inodes• Navigation functions

Inode_get_next_block:next adress block

Inode_get_pos_block_from_byte:block adress which contains the byte number



Inodes• Inode low level function

Function in charge allocating and freeing blocks

Two choices: Allocate and stop (no more free

space) Don’t allocate if there is not enough

space Take two parameters:

A pointer to an inode A new size for the inode



Inodes• Allocating a block Allocated an indirection block if

necessary Asked to the bitmap the address of

the first free block Added it to the inode by selecting the

correspond block (10 blocks or indirections)

Indicated that the block in now occupied



Inodes• Freeing a block Flagged the address block to -1 Removed indirection block from the

inode if necessary(memory leak possible if it is not done)

Indicated that the block in now free so it can be used by another



Inodes• Basic functions

Initialization:◦Size: 0◦Type: 1 for a file (by default)◦Last access time: system time◦Addresses: -1

Last access time Inode storage:

◦Get an inode from the RAM-disk◦Save an inode to the RAM-disk


Needed in any file systemLists all the filesAllows the user to create

hierarchy◦Travel in the tree◦Main directory called root


Directories



Directories Directory implementation

◦ A special file (inode, blocks, etc…)◦ Contains the list with the following

forms 4 bytes for the address 8+1 bytes for the name Not sorted

◦ First entry: “..” referring the parent directory

◦ Root corresponds to the first inode◦ Current directory saved as a global

variable


Addition of an element◦Two steps Increase the size Add the entry at the end

Directories


Directories


Deletion of an element◦Four main steps Save the last element Find the element to delete Replace it by the last one Reduce the size of the

directory◦No memory is released


Directories


Deletion of an element◦Schemas of a deletion in the

system


Directories


Searching a file◦Main interest of directory◦Simply do a loop Entry to entry until the

directory’s size is reached Moving inside a block until there

is no more space, then go on to the next block

Exit as soon as the file is foundNathan RAMOLY, Florent HEMMI, Roméo AZANGUE, Jaouher CHOUIKH, Bayrem JRIDI, Estelle

NINTIDEM

Directories


Creation of a directory◦Four steps Check if it doesn’t already

exists Allocate an inode Create a basic inode and put

it in the allocated space Add the entry “..”


Directories


Deletion of directory◦Delete all the content Loop to read all the content File: call the specified

function Directory: recall this function

◦Set the size to 0◦Misallocate the inode◦Remove the entry from the

parent directory Nathan RAMOLY, Florent HEMMI, Roméo AZANGUE, Jaouher CHOUIKH, Bayrem JRIDI, Estelle

NINTIDEM

Directories


Printing◦ Extraction of the directory’s content as a

linked list◦ Sorting the list

Using comparison functions (Size, date and name)

Using a bubble sort algorithm ◦ Printing the list◦ Function ls

Allow user to select simply The kind of sort Ascendant or not Complete or not


Directories


Moving in the tree◦Move the current directory◦Path syntax used:

“dir1/dir2/dir3”◦Path interpretation by cut_dir◦Movement done by mini_cd Moves the current directory


Files



HEADER FUNCTIONS

mini_format mini_writemini_close mini_lsmini_cp mini_openmini_rm mini_readmini_df mini_cp

III. PROBLEMS AND SOLUTIONS


Technical problemsConceptionTestsErrors HandlingGraphical interfaceNone technical Problems

CONCLUSION


FMS with a GUIUNIX BasedFurther improvementsIndirection algorithmAlias & shortcutsImprove the block structureUpper layer applications -> OS

file management system

Documents

bayrem jridi

jaouher chouikh

florent hemmi

romo azangue

t bitmap

estelle nintidem ramoly

system designnathan

nintidem estelle handling