Questions
Syllabus
Qns. By Syllabus

Semester

Subject

Year

Tribhuwan University

Institute of Science and Technology

2081

Bachelor Level / Second Year / Fourth Semester / Science

B.Sc in Computer Science and Information Technology (CSC264)

(Operating Systems)

Full Marks: 60

Pass Marks: 24

Time: 3 Hours

Candidates are required to give their answers in their own words as for as practicable.

The figures in the margin indicate full marks.

Section A

Long Answers Questions

Attempt any TWO questions.
[2*10=20]
1.
Explain the translation of logical address into physical address using segment table with necessary diagram. List advantages and disadvantages of segmentation. [10]
2.
Find the seek time using SCAN, C-SCAN, Look and C-Look disk scheduling algorithms for processing the following request queue: 35, 70, 45, 15, 65, 20, 80, 90, 75, 130. Suppose the disk has tracks numbered from 0 to 150 and assume the disk arm to be at 30 and moving outward. [10]
3.
Explain the Sleeping Barber problem. Illustrate on how it can be solved. [10]
Section B

Short Answers Questions

Attempt any Eight questions.
[8*5=40]
4.
Explain microkernels and exokernels. [5]
5.
Consider a swapping system in which memory consists of the following hole sizes in memory order: 15 MB, 2 MB, 10 MB, 6 MB, 8 MB and 20 MB. Which hole is taken for successive segment requests of: (a) 10 MB (b) 10 MB For first fit, next fit and best fit. [5]
6.
Explain how semaphore solves the problem of critical section. [5]
7.
How do you think deadlock can be avoided? Explain. [5]
8.
Explain Inter-Process Communication in Linux. [5]
9.
List different file structures and explain them. [5]
10.
Calculate the average waiting time and turnaround time using priority algorithm (Priority 1 being the highest) for the given scenario:
PIDBrust TimeArrival TimePriorityA303B223C432D231\begin{array}{|c|c|c|c|} \hline \text{PID} & \text{Brust Time} & \text{Arrival Time} & \text{Priority} \\ \hline A & 3 & 0 & 3 \\ B & 2 & 2 & 3 \\ C & 4 & 3 & 2 \\ D & 2 & 3 & 1 \\ \hline \end{array}
[5]
11.
Explain memory-mapped I/O. [5]
12.
Write short notes on: a. Virtual Memory b. Race Condition [5]