CSIT 4th Semester
Operating Systems Board Question Paper 2081 Old Course

CSC 264-2081 ✡
Tribhuvan University
Institute of Science and Technology
2081
✡
Bachelor Level/Second Year/Fourth Semester/Science
Computer Science Information Technology (CSC 264)
(Operating Systems)
(Old Course)
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 Answer Questions
Attempt any Two question.
[2x10=20]
1.

What is inter-process communication? Consider the following processes with their arrival times and burst times:

ProcessArrival TimeBurst Time
P104
P213
P327
P432

Calculate the average waiting time and average turnaround time for FCFS and shortest job.

2.

Discuss the four necessary conditions for a deadlock to occur and explain how each condition contributes to the occurence of deadlock. Explain how deadlock should be handled.

3.

What is virtual memory and why is it important in modern operating system. Explain the concept of paging.

Section B

Attempt any Eight questions

[8x5=40]
4.

What is a system call in an operating system? Describe the process of handling system calls and the role of system programs in managing them.

5.

Define the concept of threads. Compare and contrast threads and processes.

6.

Explain the concept of a resource allocation graph. How is it used to detect deadlock in a system with multiple resources?

7.

Explain the DMA operation and how does it improve the system performance.

8.

Describe the different file access methods. Compare sequential and direct access methods.

9.

Assume the disk has 200 tracks (numbered from 0 to 199). The disk head is initially positioned at 100, and we have a sequence of requests for tracks in the following order: 55, 58, 39, 18, 90, 160, 150, 38 calculate the seek time for the disk scheduling algorithm FCFS and SCAN.

10.

Consider the page references 3, 2, 1, 5, 4, 2, 1, 3, 5, 2 find the number of page fault using LRU and optimal page replacement algorithm with 3 page frames?

11.

What are the merits and demerits of contiguous file allocation? How it differs from linked list allocation.

12.

Write short notes on:
a. Kernel modules in Linux.
b. Semaphore.