Note:
• Use Visual Studio Code editor in Linux Operating system
• Do the workshop in C programming language
• Please explain the workshop? how it works? and step to run workshop code in
terminal with command in word file
• Please use the rubric detail which is at the end of this document to evaluate and
solve workshop program
1 Introduction
In this workshop you will be implementing a file system simulator, loosely based on the historic file system used by the CP/M
system. The file system will have the following properties:
• It is a single level directory system.
• The directory entry has the following format:
struct entry {
int8_t user;
char name[9];
char extension[4];
int16_t blockcount;
int16_t block[24];
};
With the name and extension fields being C style strings. This structure is 64 bytes in size.
• The disk size is 360 Kbyte. (Thisisa31′′Single Sided Double Density disk from 1983!)
• The smallest unit of allocation is 512bytes.
• The main directory occupies the first 4 blocks of the disk (blocks 0–3), and its size is fixed, so there are 32 files in this file
system.
• No control information about it needs to be stored in the directory (i.e.no. entry).
• theonlyuserisuser1
• user-1is not a valid user and could be used to mark free directory entries.
• alongside the directory you also need a bitmap that is capable of representing all of the blocks available on the disk, this
can be a free space bitmap or an allocation bitmap, this is your choice. This structure is not stored on the disk but would
be computed by the operating system when the disk was inserted. Your bitmap will need to track the directory blocks, so
they are not allocated to another file.
You are not supposed to implement the actual storage, only the control structures of the file system. When implementing
the free bitmap you must use a bitmap, i.e. it should be an array, but each element of the array should represent several
blocks.
2 Programming Tasks
When your program starts, it will assume that the disk is unformatted, you should provide a menu that implements the following
options:
Initialise Disk initialise disk control structures, setting the blocks allocated for the bitmap to used, and marking all directory entries
as being available.
List Files in the Directory List the names, extensions, and block counts of all the valid files in the directory.
Display the Free Bitmap print the value of each of the bits in the bitmap. This need not be pretty, just a long list
of 1’s and 0’s is sufficient
Open/Create File scans the directory and if the name provided doesn’t exist then adds that file to the directory. This file will must
be used in all subsequent operations until a new file is open/created, or it is deleted.
Read File list the blocks occupied by the currently open file (not the content of these blocks as you don’t store this information)
Write File allocate another block to the currently open file. You should not reallocate blocks for the file, you should allocate the first
available block, by scanning the bitmap for the first block that is available. Each write shall add another block to the file until there
are no more slots to allocate blocks to, or the disk runs out of blocks. (There are only 24 slots available for each file.)
Delete File deallocate all blocks for the current file in the bitmap, and marks as free the directory entry for that file
You need to pay close attention to multiple boundary conditions, which exist in this file system, including the total size of the disk,
maximum size of a file, maximum number of files etc.
3 File: fs.h
/* fs.h
* Various definitions for workshop
*/
#ifndef FS_H
#define FS_H
/* Prevent multiple inclusion */
#include<stdint.h>
/* The bitmap */
#define DISKSIZE (360*1024) /* The disk size in bytes */
#define BLOCKSIZE (512) /* The block size */
#define NUMBLOCKS (DISKSIZE/BLOCKSIZE) /* number of blocks on disk */
extern uint8_t bitmap[NUMBLOCKS/8];
/* The directory entry */
struct entry {
int8_t user;
char name[9];
char extension[4];
int16_t blockcount;
int16_t block[24];
};
/* The Directory */
extern struct entry directory[32];
/* extern means its defined in another
file, prevents multiple definition
errors
*/
int toggle_bit(int block);
/* Toggles the value of the bit ’block’, in
the external array ’bitmap’.
returns the current value of the bit
Does NOT validate ’block’!!!
*/
int block_status(int block);
/* Returns the status of ’block’,
in the external array bitmap
returns 0 if bitmap bit is 0,
not 0 if bitmap bit is 1
Does NOT validate block!!!
*/
#endif
4 File: fs.c
/* fs.c
Some useful functions for workshop
*/
#include“fs.h”
uint8_t bitmap[NUMBLOCKS/8];
struct entry directory[32];
int toggle_bit(int block) {
}
}
int elem = block / 8;
int pos = block % 8;
int mask = 1 << pos;
bitmap[elem] ˆ= mask;
return bitmap[elem] & mask;
int block_status(int block) {
int elem = block / 8;
int pos = block % 8;
int mask = 1 << pos;
return bitmap[elem] & mask;
5 File: main.c
#include<stdio.h>
/* stdio.h will be found in the system path */ #include“fs.h”
/* fs.h will be found in the local path */
int main(int ac, char**av) {
}
printf(“Please make me usefuln”); return 0;
6 File: makefile
all: caseE
caseE: main.o fs.o
$(CC) -o $@ $ˆ
Workshop Rubric Detail: