College of Engineering and Science
NIT1202 Operating Systems Trimester 2, 2018
Assignment 1, Part 1 (25%)
The aim of this assessment is to understand the functions of an operating system regardless of the hardware that houses it. The operating system can be represented as a pyramid of four essential managers – Memory, Processor, Device and File Managers. This assessment helps you to understand the functions of the first two managers.
Due: Friday 7 September 2018, 5 pm (paper and electronic copy)
Answer the following questions:
1. Write a one-page (400 words) review on an article about the subject of operating systems that appeared in a recent (since Jan 2016) computing magazine or academic journal. Give a summary of the article, including the primary topic, your own summary of the information presented, and the author’s conclusion. Give your personal evaluation of the article, including topics that made the article interesting to you and its relevance to your own experience. Be sure to cite your source (APA referencing).
2. Given the following information:
Memory Block List:
Requested Memory Block Memory Block Size
Job A 57K Block 1 900K
Job B 920K Block 2 910K
Job C 50K Block 3 200K
Job D 701K Block 4 300K
a. Use the best-fit algorithm to indicate which memory blocks are allocated to each of the four arriving jobs.
b. Use the first-fit algorithm to indicate which memory blocks are allocated to each of the four arriving jobs.
[5 + 5 = 10 marks]
3. Compare and contrast internal fragmentation and external fragmentation. Explain the circumstances where one might be preferred over the other.
[6 + 4 = 10 marks]
4. If a program has 471 bytes and will be loaded into page frames of 100 bytes each, and the instruction to be used is at byte 132, answer the following questions:
a. How many pages are needed to store the entire job?
b. Compute the page number and exact displacement for each of the byte addresses where the data is stored. (Remember that page numbering starts at zero).
[5 + 5 = 10 marks]
5. Given that main memory is composed of only three page frames for public use and that a seven-page program (with pages a, b, c, d, e, f, g) that requests pages in the following order:
a, c, a, b, a, d, a, c, b, d, e, f
a. Using the FIFO page removal algorithm, indicate the movement of the pages into and out of the available page frames (called a page trace analysis) indicating each page fault with an asterisk (*). Then compute the failure and success ratios.
b. Increase the size of memory so it contains four page frames for public use. Using the same page requests as above and FIFO, do another page trace analysis and compute the failure and success ratios.
c. What general statement can you make from this example? Explain your answer.
[5 + 5 + 5 = 15 marks]
6. Five jobs arrive nearly simultaneously for processing and their estimated CPU cycles are, respectively: Job A = 12, Job B = 2, Job C = 15, Job D = 7, and Job E = 3 ms.
a. Using FCFS, and assuming the difference in arrival time is negligible, in what order would they be processed? What is the total time required to process all five jobs? What is the average turnaround time for all five jobs?
b. Using SJN, and assuming the difference in arrival time is negligible, in what order would they be processed? What is the total time required to process all five jobs? What is the average turnaround time for all five jobs?
[5 + 5 = 10 marks]
7. Given the following information:
A 0 15
B 2 2
C 3 14
D 6 10
E 9 1
Calculate the start time and finish time for each of the five jobs using each of the following scheduling algorithms
d. Round robin (using a time quantum of 5, but ignore the time required for context switching and natural wait)
Cycle FCFS SJN SRT
A 0 15 Start:
B 2 2 Start:
C 3 14 Start:
D 6 10 Start:
E 9 1 Start:
Due: Friday, 7 September 2018, 5:00 pm
Late assignments without a valid excuse will be penalised at the rate of 10% per day, that is, an assignment is marked out of 90% for 1 day late, 80% for 2 days late, etc. and after one week (7 days) assignments will not be accepted at all. (Example: An assignment due in on Friday, but handed in on the next Monday morning is marked out of 70%.)
Extensions: If students are adversely affected by life circumstances then they may, at the discretion of the Unit Coordinator, be granted up to one week as an extension on the due date. If students’ work is affected to a substantial degree, requiring more than the few days extension, then they may apply for Special Consideration.
You are required to submit both a paper and an electronic copy of your assignment to your tutor. Electronic submission needs to be made via VU Collaborate Assessment Dropbox. Electronic means may be used to check for plagiarism.
Layout and content:
Assignment must be submitted with a proper layout and content.
Weight: This task is worth 25% of the assessment for the unit.
Your answers should be in your own words. Random oral testing following the submission of assignments may be conducted.
It is important to learn from the work of others and you are encouraged to explore the library, World Wide Web resources and have discussions with other students. However, work for assessment must be entirely the student's own work.
Plagiarism, that is copying or using the work of others without giving details of the source of information is not acceptable. All sources used and any collaboration in the exploratory work for an assignment must be clearly acknowledged using standard academic referencing.
You must not allow other students to copy your work and must take care to safeguard against this happening. In cases of copying, normally all students involved will be penalised equally; an exception will be if you can demonstrate the work is your own and you took reasonable care to safeguard against copying.
References: (refer to the unit description for additional references)
McIver-McHoes, A. & Flynn, I. (2014). Understanding Operating Systems, 7th ed. Cengage Learning.
NIT1202 Operating Systems
Trimester 2, 2018
Assignment – Part 1 Marking Scheme
Name: __________________________ Student ID: _________________________
Topic related to operating systems – 8 marks
Opinion – 5 marks
Summary - 5 marks
Conclusion – 4 marks
References – 3 marks
No title page, table of contents, page numbers
Poor presentation, no acknowledgements, poor references