File Systems
In this project, you will design and implement a simplified FAT like file system in C or C++. Part 1
Design a file system that uses File Allocation Table (FAT12) structure to keep your files. Your file system will use, a i-node structure like Fig 4.30 and Fig 4.31 of your textbook (all possible FAT12 blocks are supported). Your file attributes will include size, last modification date and time, and name of the file. Write a design report that specifies the following
- Define your directory structure and directory entries;
- Define how and where you keep the free blocks;
- Define your superblock that contains crucial information about the file system such as the block size, root directory position, block positions, etc.
Your report should include the function names of your source code that handles the file system operations listed in the table of Part 3.
Part 2
Write a C/C++ program that creates an empty file system as a (16 MB max) Linux file. This file will include all the information about your file system including the super block, data blocks, free blocks, directories, data, etc. The sample run of the program will be like
makeFileSystem 4 mySystem.dat
where 4 is the block size of the file system in KB. mySystem.dat is the Linux file that contains all the file system. When you work on the file system, this file contains all the information for the file system. Note that the size of mySystem.dat will be exactly the maximum according to table Fig 4.31 MB whether it contains any information or not. Part 3
You will write a program that performs file system operation on the file system. The program will work like following
fileSystemOper fileSystem.data operation parameters
where fileSystemOper is your program, fileSystem.data is the file system data file that you have created in Part 2. You will keep modifying the same fileSystem.data file for all your operations. Allowable operations and parameters for these operations are given below in the following table.
| Operation | Parameters | Explanation | Example |
| dir | Path | Lists the contents of the directory shown by path on the screen. | fileSystemOper fileSystem.data dir lists the contents of the root directory. The output will be similar to dir command of DOS |
| mkdir rmdir | Path and dir name | Makes or removes a directory | fileSystemOper fileSystem.data mkdir ysafname makes a new directory under the directory ysa if possible. These two works exactly like mkdir and rmdir commands of DOS shell |
| dumpe2fs | None | Gives information about the file system. | fileSystemOper fileSystem.data dumpe2fs works like simplified and modified Linux dumpe2fs command. It will list block count, free blocks, number of files and directories, and block size. Different from regular dumpe2fs, this command lists all the occupied blocks and the file names for each of them. |
| write | Path and file name | Creates and writes data to the file | fileSystemOper fileSystem.data write ysafile linuxFile Creates a file named file under usrysa in your file system, then copies the contents of the Linux file into the new file. |
| read | Path and file name | Reads data from thefile | fileSystemOper fileSystem.data read ysafile linuxFile Reads the file named file under /usr/ysa in your file system, then writes this data to the Linux file. This again works very similar to Linux copy command. |
| del | Path and file name | Deletes file from the path | fileSystemOper fileSystem.data del ysafile Deletes the file named file under ysafile in your file system. This again works very similar to Linux del command. |
Here is a sequence file system operation commands that you can use to test your file system. Suppose you have a file named linuxFile.data in your Linux current directory.
makeFileSystem 4 mySystem.data fileSystemOper fileSystem.data mkdir usr fileSystemOper fileSystem.data mkdir usrysa fileSystemOper fileSystem.data mkdir binysa ; Should print error!
fileSystemOper fileSystem.data write usrysafile1 linuxFile.data fileSystemOper fileSystem.data write usrfile2 linuxFile.data
fileSystemOper fileSystem.data write file3 linuxFile.data
fileSystemOper fileSystem.data dir ; Should list 1 dir, 1 file fileSystemOper fileSystem.data del usrysafile1 fileSystemOper fileSystem.data dumpe2fs
fileSystemOper fileSystem.data read usrfile2 linuxFile2.data
cmp linuxFile2.data linuxFile.data ; Should not print any difference Notes
- Always be careful about the errors, such as bad block sizes, bad file names, non-existent files or directories, etc.
- Run experiments that uses up all of your data blocks.
- Try to get fragmentation and show your fragmented file system using the dumpe2fs
- Do not use any code from any other source even a single line!
Homework Instructions
- Download and Install Vmware Player from Official site.
- Download and install our virtual machine from https:\google.comopen?
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