CSIT 4th Semester
Operating Systems Board Question Paper 2080

CSC 264-2080 ✡
Tribhuvan University
Institute of Science and Technology
2080
✡
Bachelor Level/Second Year/Fourth Semester/Science
Computer Science Information Technology (CSC 264)
(Operating Systems)
(New 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.

How DMA operation is performed? Consider a disk with 200 tracks and the queue has random requests from different processes in the order: 45, 48, 29, 17, 80, 150, 28, and 188. Find the seek time using FIFO, SSTF and SCAN. Assume that the initial position of head is at 100.

2.

How do you distinguish between deadlock and starvation? Describe the necessary conditions for deadlock. Explain the working mechanism of TLB.

3.

Why do we need to schedule process? Find the average waiting time and average turnaround time for the following set of processes using FCFS, SJF, RR(Quantum: 3) and Shortest Remaining Time Next.

ProcessCPU Burst TimeArrival Time
P1200
P22515
P31030
P41545

Section B

Attempt any Eight questions

[8x5=40]
4.

What is system call? Describe the transition between different states of a process.

5.

Discuss about contiguous and linked list allocation approach in implementing files.

6.

Why do we need virtual memory? Describe the structure of a page table.

7.

Illustrate the term safe and unsafe state in deadlock prevention with a scenario.

8.

How lock variable is used in achieving mutual exclusion? Describe.

9.

Why do we need hierarchical directory system? Explain the structure of a disk.

10.

Find the number of page faults using FIFO and LRU for the reference string, 4, 3, 6, 1, 7, 6, 1, 2, 1, 2 with frame size 3.

11.

Define working set. How does clock page replacement algorithm work?

12.

Write short notes on
a. Inodes
b. RAID