Midterm Exam Project File Systems

In this project, you will design and implement a simplifies UNIX like file system in C or C++. This project does not use MIPS or SPIM, so it is completely independent of your other homework assignments. This will count as midterm exam for this course.

Part 1

Design a file system that uses i-nodes blocks and data blocks to keep your files. Your file system will use, a i-node structure like Fig 4.33 of your textbook (single link, double link and triple link i-nodes). Your directory, i-node block, data block structure will be similar to Fig 4.34 of the textbook. Your file attributes will include size, last modification date and time, and name of the file. No permissions or owner attributes will be kept. Write a design report that specifies the following

    • Define your directory structure and directory entries;

    • Define how you keep the free blocks and free i-nodes;
    • Define your i-node structure

    • Define your superblock that contains crucial information about the file system such as the block size, i-node positions, 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 1 MB Linux file. This file will include all the information about your file system including the i-nodes, data blocks, free blocks and i-nodes, directories, data, etc. The sample run of the program will be like

makeFileSystem 4 400 mySystem.dat

where 4 is the block size of the file system in KB for both data blocks and i-node blocks, and 400 is the number of free i-nodes for an empty file system. 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 1 MB all the time 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.

I

Operation
Parameters
Explanation

Example
list
Path
Lists the contents of

fileSystemOper fileSystem.data list “/”


the directory shown by








path on the screen.

lists the contents of the root directory. The output will




be like ls –l
mkdir
Path and dir
Makes or removes a

fileSystemOper fileSystem.data mkdir

name
directory

“/usr/ysa”









rmdir



makes a new directory under the directory “ysa” if









possible. These two works exactly like mkdir and




rmdir commands of Linux shell
dumpe2fs
None
Gives information

fileSystemOper fileSystem.data dumpe2fs


about the file system.










works like simplified and modified Linux dumpe2fs




command. It will list block count, i-node count, free




block and i-nodes, number of files and directories, and




block size. Different from regular dumpe2fs, this













command lists all the occupied i-nodes, blocks and the





file names for each of them.






write
Path and
Creates and writes data

fileSystemOper fileSystem.data write

file name
to the file

“/usr/ysa/file” linuxFile













Creates a file named file under “/usr/ysa” in your




file system, then copies the contents of the Linux file




into the new file. This works very similar to Linux




copy command.
read
Path and
Reads data from the

fileSystemOper fileSystem.data read

file name
file

“/usr/ysa/file” 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
Deletes file from the

fileSystemOper fileSystem.data del

file name
path

“/usr/ysa/file”













Deletes the file named file under “/usr/ysa” in




your file system. This again works very similar to




Linux del command.

Operations below are bonus (20 points)
ln
Source and
Hard linking between
fileSystemOper fileSystem.data ln

destination
2 files
“/usr/ysa/file1” “/usr/ysa/file2”





path and

Allows more than one filename to refer to the same

file names





file



Linux ln command
lnsym
Source and
Symbolic linking
fileSystemOper fileSystem.data lnsym

destination
between 2 files
“/usr/ysa/file1” “/usr/ysa/file2”





path and

Linux ln-s command

file names




II

fsck

none

Simplified File system check
fileSystemOper fileSystem.data fsck


Just print the two table of Fig 4.27 of your textbook for both i-nodes and blocks


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 4 400 mySystem.data
fileSystemOper fileSystem.data mkdir “/usr”
fileSystemOper fileSystem.data mkdir “/usr/ysa”
fileSystemOper fileSystem.data mkdir “/bin/ysa”    ; Should print error!

fileSystemOper fileSystem.data write “/usr/ysa/file1” linuxFile.data fileSystemOper fileSystem.data write “/usr/file2” linuxFile.data fileSystemOper fileSystem.data write “/file3” linuxFile.data
fileSystemOper fileSystem.data list “/”    ; Should list 1 dir, 1 file
fileSystemOper fileSystem.data del “/usr/ysa/file1”
fileSystemOper fileSystem.data dumpe2fs
fileSystemOper fileSystem.data read “/usr/file2” linuxFile2.data
cmp linuxFile2.data linuxFile.data    ; Should not print any difference
fileSystemOper fileSystem.data ln “/usr/file2” “/usr/linkedfile2”
fileSystemOper fileSystem.data list “/usr"
fileSystemOper fileSystem.data write “/usr/linkedfile2” linuxFile.data
fileSystemOper fileSystem.data dumpe2fs
fileSystemOper fileSystem.data lnsym “/usr/file2” “/usr/symlinkedfile2”
fileSystemOper fileSystem.data list “/usr"
fileSystemOper fileSystem.data del “/usr/file2”

fileSystemOper fileSystem.data list “/usr" ; Should see likedfile2 is there, symlinkedFile2 is there but..
fileSystemOper fileSystem.data write “/usr/symlinkedfile2” linuxFile.data ;    Should print error!
fileSystemOper fileSystem.data dumpe2fs

Notes

    1. Always be careful about the errors, such as bad block sizes, bad file names, non-existent files or directories, etc.

    2. Run experiments that uses up all of your i-nodes and data blocks.
    3. Try to get fragmentation and show your fragmented file system using the dumpe2fs command.

    4. Do not use any code from any other source even a single line!

What to submit

Follow all instructions below, otherwise you will get penalty on your grade for each missing instruction.

    • Name all files as they specified below exactly.

    • Zip all files (6 files below) into only one file and name it like below CSE312_Midterm_StudentNumber_Surname_Name.zip

o  Do not use other than .zip extensions

    • If you want to specify problems such as run time errors, compilation error, or etc., please use only one ReadMe file to write those into.

        o Do not put them into your Part_1.pdf report

    1. Part_1.pdf: This will contain your report as the output of Part 1.
    2. Part_2_Program.zip : This will contain your program as the output of Part 2.
        a. All the files that are required to run your program of Part 2 must in this zip file.
    3. Part_3_Program.zip : This will contain your program as the output of Part 3.

        a. All the files that are required to run your program of Part 3 must in this zip file.
    4. fileSystem.data : This file is your file system as the output of Part2.
    5. commands.txt : This is the file containing the file system commands that are developed and tested.
    6. readMe.txt: Described above.

III

General Homework Guidelines

    1. No cheating, No copying, No peaking to other people homework
    2. Follow the instructions very carefully.

    3. Send required files only. Do not share your whole file system with us.
    4. If you fail to implement one of the requirements, leave it be. Do not send an empty file
    5. Respect the file names! Our HW grading is case-sensitive.

    6. Failing to comply any of the warnings above will result in getting a 0 for your current homework.

Homework Instructions

    1. Download and Install Vmware Player from Official site.

    2. Download and install our virtual machine from https://drive.google.com/open?id=1YppX3lNkyTsHV_lvA4w9TomNCUkpLeEg






















































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