CS 33211 Operating Systems
Project #3

Due via e-mail by 11:59 on Wednesday, April 25th

IMPLEMENTING INDEXED FILE SYSTEM

Write a program that implements a rudimentary 2-level indexed file
system. Your program should create a file named DISK and simulate disk
operations on this file. The disk blocks are to be exactly 10
bytes. The disk has a single track (all blocks are stored
sequentially). The track size is 500 blocks.  In communication with
the disk you should use random access read and write functions.  Check
the corresponding man-pages for their operation.

    man -S 3p write

The only allowed block size that you can read from or write to the
disk is 10 bytes. Your filesystem is to have a single unnamed
file. Its i-node will be stored in the first block of the disk. The
i-node has two types of information. In the first byte - file size is
stored. The remaining bytes are used to store references (block
numbers) to the blocks where file data is stored. Use byte-size
integers to store block numbers. Notice that the i-node can store 10
references. The first eight references are directly to the data
blocks. The last reference is to the single indirect index block. This
index block should contain additional 10 references to data blocks.
If the block is not allocated it should contain 0. Notice that a block
can be partially filled and the program should use the file size to
determine where the file data ends.

Your program should be able to accept information from the standard
input and write to the simulated file. The input is accepted until
keyword ENDFILE is entered. All the information should be written to
the file except the keyword ENDFILE. The program should handle files
that are too large gracefully (print an error and quit).  After
writing the file your program should print to standard output the
contents of your disk in human-readable format (do not print in
hexadecimal or other formats that are hard to understand). Then the
program should read the file data back and print it to standard
output. You are not allowed to store the data in your program between
writing to the disk and reading it back.


Submitting Your Project and Grading

You have to submit your project to the teaching assistant by
e-mail. She will acknowledge the receipt of your project within a
day. Send her only the source files. You can send them either as
tar-achieves or as attachments.

The programming project is worth 50 points. Late projects are
accepted. Late policies are outlined in the syllabus. The grading will
be such that the working program submitted a few days late will
receive a higher grade that the program that does not work but is
submitted. If your program still does not work, submit a text file
specifying how the program fails (does not compile, fails test
examples, etc.), what you think the reason is and how it can be
fixed. You may be given partial credit.