Questions
Syllabus
Qns. By Syllabus

Semester

Subject

Year

Tribhuwan University

Institute of Science and Technology

2078

Bachelor Level / Second Year / Third Semester / Science

Bachelors in Information Technology (BIT204)

(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.
Suppose that a disk has 100 cylinders, numbered 0 to 99. The drive is currently serving a request at cylinder 45. The queue of pending request, in FIFO order is: 88, 72, 13, 74, 48, 9, 22, 50, 35 and 30. What is the total distance (in cylinders) that the disk arm moves to satisfy all pending request for each of the following disk scheduling algorithms? a) FCFS b) SCAN c) SSTF[10]
2.
Why virtual memory technique is used in the computer system? What is logical address? Explain the process of conversion of logical address to physical address in single level paging scheme.[10]
3.
What is critical section? What are the operations that can be performed on the semaphore? Explain the solution to producer consumer problem using semaphore.[10]
Section B

Short Answers Questions

Attempt any Eight questions.
[8*5=40]
4.
Draw and describe the 5-state process model. [5]
5.
What is kernel? Differentiate between monolithic and microkernel structure. [5]
6.
What is DMA? Explain how it works in brief with suitable diagram. [5]
7.
What are different types of file? Describe the sequential and random access of files. [5]
8.
what is deadlock? What ate necessary conditions for deadlock? Explain. [5]
9.
What is thread? Explain user level thread and kernel level thread. [5]
10.
A 2 GB hard disk has 2 KB block size, calculate the size of bitmap for bitmap based free space management. [5]
11.
What is an operating system? Differentiate between time sharing and real time operating system. [5]
12.
Consider the following set of processes, with the length of CPU brust time given in milli seconds. The processed are assumed to have arrived in the order A, B, C and D all at time 0. What is the turnaround time and waiting time for the scheduling algorithms, RR (quantum = 3) and Priority Algorithm.

$\begin{array}{|c|c|c|}\hline \text{Process} & \text{CPU Burst} & \text{Priority} \\ \hline A & 8 & 3 \\ B & 9 & 1\,(\text{Lowest}) \\ C & 10 & 2 \\ D & 6 & 4\,(\text{Highest}) \\ \hline \end{array}$
[5]