Past Question 2079 View
Tribhuvan University
Institute of Science and Technology
2079
Bachelor Level / fourth-semester / Science
Computer Science and Information Technology( CSC264 )
Operating System
Full Marks: 60 + 20 + 20
Pass Marks: 24 + 8 + 8
Time: 3 Hours
Candidates are required to give their answers in their own
words as far as practicable.
The figures in the margin indicate full marks.
Section A
Long Answer Question
1Discuss about single level and two level directory system.
Consider the following process and answer the following questions.
|
Process |
Allocation |
Max |
Available |
|
A B C
D |
A B C
D |
A B C
D |
|
|
P0 |
0 0
1 2 |
0 0
1 2 |
1 5
2 0 |
|
P1 |
1 0
0 0 |
1 7
5 0 |
|
|
P2 |
1 3
5 4 |
2 3
5 6 |
|
|
P3 |
0 6
3 2 |
0 6
5 2 |
|
|
P4 |
0 0 1
4 |
0 6 5
6 |
a. What is the content of matrix Need?
b. Is the system in safe state?
c. If P1 request (0,4,2,0) can the request be granted
immediately.
2When does race condition occur in inter process
communication? What does busy waiting mean and how it can be handled using
sleep and wakeup strategy?
3Define shell and system call. suppose a disk has 201
cylinders, numbered from 0 to 200. At same time the disk arm is at
cylinder 95, and there is a queue of disk access requests for cylinders
82,170,43,140,24,16 and 190. Calculate the seek time for the disk scheduling
algorithm FCFS,SSTF,SCAN and C-SCAN.
Section B
Short Answer Questions
4Distinguish between starvation and deadlock . How does the
system schedule process using multiple queues?
5List any two demerits of disabling interrupt to achieve
mutual exclusion. Describe about fixed and variable partitioning
6For the following dataset, compute average waiting time for
SRTN and SJF.
|
Process |
Arrival Time |
Burst Time |
|
P0 |
0 |
7 |
|
P1 |
2 |
4 |
|
P2 |
4 |
1 |
|
P3 |
5 |
4 |
7Discuss the advantages disadvantages of implementing file
system using Linked List.
8Consider the page references 7,0,1,2,0,3,0,4,2,3,0,3,2,
Find the number of page fault using OPR and FIFO, with 4 page frame.
9Describe the working mechanism of DMA.
10What is the task of disk controller ? List some drawback
of segmentation.
11Write the structure and advantages of TLB.
12Why do we need the concept of locality of reference ? List
the advantages and disadvantages of Round Robin algorithm.