CSE 2312 - Assignments - Assignment 4

The assignment will be graded out of 100 points. Submit a ZIPPED file (no other formats will be accepted) called assignment4.zip, containing the following three documents:

A document entitled answers.xxx (where you replace xxx with whatever extension is appropriate, depending on the file format you use), that contains answers to the non-programming tasks (i.e., answers to tasks 2, 3, 4, 5). Acceptable file formats are plain text, Word document, OpenOffice document, and PDF. Put your name and UTA ID on the first line of the document.
File task1.xxx (where xxx depends on your choice of programming language) containing your solution to the programming task (i.e., the solution to task 1). Make sure that your solution runs on omega.

Submit your assignment4.zip file to Blackboard before the deadline. You will be able to revise your answers until the deadline with no penalty.

IMPORTANT: By submitting your answers, you are certifying that you have followed the UTA standards of academic integrity, and that these answers have been exclusively your own work. All students enrolled in this course are expected to adhere to the UT Arlington Honor Code:

I pledge, on my honor, to uphold UT Arlington's tradition of academic integrity, a tradition that values hard work and honest effort in the pursuit of academic excellence. I promise that I will submit only work that I personally create or contribute to group collaborations, and I will appropriately reference any work from other sources. I will follow the highest standards of integrity and uphold the spirit of the Honor Code.

Task 1 - Programming (60 pts.)

Write a program (in C, C++, Java, or Python) that can do Hamming encoding and decoding of 7-bit words. We will interpret each 7-bit original word as an ASCII code, that represents a single character.

To make it easy to read and modify input and output files using a text editor, our input and output will be TEXT files, not binary files. As an example, consider 7-bit word 1010100.

Binary number 1010100 is number 84 in decimal representation.
84 is the ASCII code of character 'T'.
In the text file where we store uncoded data, we store this binary number as string '0110010'.
The Hamming code for 1010100 is 00110101100.
In the text file where we store coded data, we store this binary number as string '00110101100'.

If you are using C, C++, or Java, your program should take three command line arguments: number, input_file, output_file. Similarly, if you are using Python, your function should take in three arguments: number, input_file, output_file. Your program should behave as follows:

If number is 0, then the input file 7-bit long original words. Each chunk of 7 characters represents an ASCII code in binary. The output file should contain the 11-bit Hamming coding of each such chunk. The Hamming coding of each 7-character chunk should be stored as a string of '0' and '1' characters.
If number is 1, then the input file 11-bit long Hamming codewords. The output file should contain the original 7-bit ASCII code for each such chunk. This ASCII code should be saved as a string of 7 characters that are '0' or '1'.

You should assume that the input file ONLY contains only characters '0' and '1', nothing else (no spaces, new lines, etc.). You should enforce that your output file follows the same convention, and also contains ONLY characters '0' and '1'.

To help you get started, we provide the following resources:

File task1.c contains most of the code that you need for the solution. Feel free to use this code, and add the code that is needed to convert this code into a complete solution for this task. If you use this file, you just need to implement these two functions, which have been left undefined:
- int convert_to_original_word(char * input_buffer, char * output_buffer);
In the opinion of the instructor, using the code in task1.c is probably the easiest way to solve this task (my solution is about about 80-100 additional lines of code added to task1.c). Still, if you choose so, you are free to write your own code from scratch in C, C++, Java, or Python.
File in1.txt is a test file that (in uncoded form) the binary pattern representing text "The kangaroo is an animal that lives in Australia.".
File coded1.txt is the coded version of file in1.txt.
File coded2.txt is a corrupted version of file coded1.txt, that includes 9 errors, at positions 0, 6, 12, 18, 24, 30, 36, 42, 48. Your solution should be able to correct these errors.
File coded3.txt is a corrupted version of file coded1.txt, that includes one error at the last word. Your solution should NOT be able to correct this error.

While we have provided these test files, we will test your solutions with different test files, so your solution should be able to handle any file following the format we have specified (containing only '0' and '1' characters).

Submit your solution to this task as a file called (depending on the programming language you use) task1.c, task1.cpp, task1.java, or task1.py. Your solution needs to run on omega.uta.edu, otherwise you will receive at most half credit.

Task 2 (5 pts.)

(This is Problem 8 from Chapter 2 of the textbook).

Compute the data rate of the human eye using the following information. The visual field consists of about 10⁶ elements (pixels). Each pixel can be reduced to a superposition of the three primary colors, each of which has 64 intensities. The time resolution is 100 msec.

Task 3 (5 pts.)

(This is Problem 9 from Chapter 2 of the textbook).

Compute the data rate of the human ear from the following information. People canhear frequencies up to 22 kHz. To capture all the information in a sound signal at 22kHz, it is necessary to sample the sound at twice that frequency, that is, at 44 kHz. A 16-bit sample is probably enough to capture most of the auditory information (i.e., the ear cannot distinguish more than 65,535 intensity levels).

Task 4 (10 pts.)

(This is Problem 17 from Chapter 2 of the textbook).

The disk illustrated in Fig. 2-19 has 1024 sectors/track and a rotation rate of 7200RPM. What is the sustained transfer rate of the disk over one track?

Task 5 (20 pts.)

A company has 1000 RAID-5 arrays. Each array has 10 disks. On average, a disk fails every 20,000 hours. When a disk fails in a RAID-5 array, it takes one hour to fix the array. Fixing the array involves taking out the broken disk, putting in a new disk, and storing the right data on the new disk. If, during that hour, another disk fails on the array that is getting fixed, the data on the array is lost.

Under these assumptions:

On average, every how many hours do company technicians need to fix a RAID-5 array?
On average, every how many hours does the company lose data?
If you were asked to propose an alternative RAID version, perhaps even a new RAID version (that is not RAID-0, RAID-1, RAID-5), that would significantly reduce the frequency at which the company loses data, what would you propose?

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