QUESTION BANK

Course: B.Tech Branch:

CSE
Sem:3rd
Subject: OS
UNIT-1

1. What is an Operating System? What it does as a Resource Manager?

2. Briefly explain any 5 services of Operating System, how it provides
convenience to the user.
3. What are the different types of operating system?
4. Explain Layered Approach of Operating System.
5. What are the objective of Operating System.
6. Differentiate between time sharing system and real time system.
7. Define kernal .
8. Explain operating system structure with suitable diagram.
UNIT-2

1. Draw and briefly explain Process state transition diagram.

2. Explain Dining philosopher problem with its possible solution.
3. Give a Mutual-exclusion solution for Producer-consumer problem of ritical
section with algorithm and example.
4. What is cpu scheduling? If the different jobs and their arrival time and burst
time is given below find the average turnaround time and average waiting time
using FCFS and SJF.
Process Arrival time Burst time
0 0
4
1 1
5
2 2
2
3 3
3
4 4
6

5.Define Race condition with example.

6. Write difference between process and thread.
 7. Consider a system with set of process with burst time (in ms) and

Drpriorities (consider 1 to be highest).

Draw Gantt chart and find Average waiting time for pre-emptive priority
scheduling.

Process Burst time Priority Arrival time

P1 10 3
0
P2 5 2
1
P3 2 1
2

9. Draw and explain Process state diagram.

10. Write short notes on: (1) the process control block (2) The critical section
problem.
11. Define Semaphores? Give the solution of producer consumer problem using
semaphore.

UNIT-3
1. What is deadlock? Give any real-life example of deadlock.
2. What are the four necessary conditions for deadlock occurrence? Explain.
3. Explain various method of avoid deadlock.
4. Determine whether a given system is in a deadlock. Consider the following
snapshot of a system:
Process Allocation Max Available
A B C A B C A B C
P0 0 1 0 7 5 3 3 3 2
P1 2 0 0 3 2 2
P2 3 0 2 9 0 2
P3 2 1 1 2 2 2
P4 0 0 2 4 3 3
Answer the following using Banker’s algorithm.
i) What would be the need matrix?
ii) Is the system in a safe state?
 iii)If a request from process P1 arrives for (1,0,2) can be granted
immediately?
5. Explain various method for recovery from deadlock.
6. What is safe and unsafe state?
7. Explain the deadlock recovery method.
8. Explain how the deadlock can be prevented.
9. Define deadlock.
10. Explain how deadlock can be prevented on the basic of all deadlock
conditions.
11. Consider the following system with processes from P0 to P4.

Process Allocation Max Available

A B C A B C A B
C

P0 0 1 0 7 5 3 3 3
2

P1 2 0 0 3 2 2

P2 3 0 2 9 0 2

P3 2 1 1 2 2 2

P4 0 0 2 4 3 3

Using banker’s algorithm find the following:

i) Content of need matrix
ii) Is the system in a safe state? If yes then what is the safe sequence?
12. Write short notes on:
i) Resource allocation graph
ii) Recovery from deadlock

Unit- 4
1. Why we need Pagging?
2. What is the need of page replacement? Explain any one-page replacement
algorithm with suitable example.
3. What is Thrashing? State the cause of thrashing.
4. Write short notes on:
i) Virtual Memory
ii) Cache memory
5.Define Logical and Physical Address.
 6. Explain the concept of segmentation with suitable diagram.

7.Determine the number of page fault having 3 frames available in memory, when

reference to pages occur in order:

4,7,6,1,7,6,1,2,7,2
i) OPR
ii) LRU

8. What is virtual memory? How it implemented using demand paging explain?

9. What is virtual memory?

10. Explain the address translation from logical to physical address.

11. Write short notes on:

i) Paging

ii) Segmentation

13. Consider a reference string 4,7,6,1,7,6,1,2,7,2, the number of frames in

the memory is 3 find out the number of page faults respectively to

i)Optimal

ii) LRU

iii) FIFO

13.What is swapping?

14.Explain internal and external fragmentation with example.

15. Explain demand page concept in details.

16. Explain contiguous memory allocation techniques.

17.Explain non-contiguous memory allocation techniques.

18.Explain what are the different contiguous memory allocation algorithm with

Example.

19. Explain fixed partition with its limitations.

20. Explain variable partition with its advantage s and limitation.

UNIT-5
1. What is DMA?
2. Difference between program driven and interrupt driven input/output.
3. Explain kernel and buffer cache architecture of Unix operating system.
4. Consider a disk with 200 tracks and the queue has random request from
different processes in the order: 55,58,38,18,90,160,150,38,184
Initially aim is at 100. Find the average seek length using FIFO, SSTF, scan
and C-scan algorithm
5. Define File and its attributes.
6. Describe File access methods in detail.
7. Suppose the moving head disk with 200 track is currently serving a request
for track is 143.if the queue request for track is kept in FIFO order:
86,147,91,177,94,150.
What is the total head movement for the following scheduling schemes:
i) FCFS
ii) SSTF
8. What is inode? Write about namei algorithm.
9. What are the different operation performed on File?
10. Explain free space Management and its techniques.
11. Describe Various file accessing method with its advantage and
disadvantages.
12. What do you mean by input/output Buffering? Explain with their types.