Simulating UNIX/Linux file system

This a program to create hierarchical file system simulation written in c++

It creates a virtual disk on your system of specified size and lets you perform the following operations:

• create/ read/ delete/ recover/ remove a file
• create a directory
• switch between different directories
• list files

Download and run

$ git clone https://github.com/Rishija/diskSimulation.git
$ cd project
$ make
$ ./disk

Working

Approach

All read and write operations are done sector by sector. Some sectors are reserved for storing status of other sectors. As soon as user creates a new directory, 2 sectors are reserved for it. Entry for any dir/file is of 32 bytes. Whenever changes are made to any sector, its status is changed simultaneously.

Calculations

Default sector size is set to 512 bytes (can be changed but calculations change accordingly).

Example:

• Size of the disk(in mb) = 1
• Size of the disk(in bytes) = size_in_mb * ( 2 ^ 20 ) = 2 ^ 20
• Size of each sector = 2 ^ 9
• Total no. of sectors = size of disk(in bytes) / sector_size = ( 2 ^ 20 ) / ( 2 ^ 9 ) = 2 ^ 11
• Status is of 4 bytes
• Each sector contains status of ( 2 ^ 7 ) sectors
• Reserved sectors = Total_no_of_sectors / ( 2 ^ 7 ) = 2 ^ 4
• 2 Sectors are reserved for root directory (Sector no: reserved sectors and reserved sectors+1)

File operations:

• Create
• Read
• Delete
• Recover
• Remove

Directory operations:

• Access parent directory
• Move to root directory
• Change current directory

Helping Functions:

• Read sector
• Write sector
• Status of a sector
• Update status of sector
• Check if file/directory already exists
• Storing path to working directory
• List files in a directory/Disk

Sample screenshots