Operating system Unit 1

1. a) Define 'Operating system'. Write functions of operating system as a manager of the

resources. {S16}
b) Define essential properties of the following types of operating system? {S16}
i) Batch. ii) Interactive.
iii) Time sharing. iv) Real time.
c) What is OS? Explain Batch and Distributed operating system in brief. {S17}
d) What is system call? Explain different types of system calls.
e) Distinguish between multitasking, multiprogramming and multiprocessor system. {S18}
f) What is system call? Discuss various types of system calls. {W16}
g)Explain the types of operating system? {W16}
h) Explain various services provided by Modern operating system. {W17}
i)Explain how multiprogramming OS is differ from batch OS? {W17}
j) Explain different types of kernel.
k) Explain following types of operating system. {W18}
i) Multiprogramming OS ii) Multitasking OS
iii) Real time OS iv) Distributed System
l) Define operating system. What are different services offered by OS? {W19}
m) What is operating system? Explain batch distributed and time sharing operating system.
{W19}
n) List and elaborate on various system components used by a process. {W19}
2. a) Describe the difference between symmetric and asymmetric multiprocessing. What are
advantages and disadvantages of multiprocessor systems? {S16}
b) Give reasons why caches are useful. If cache can be made as large as the device for
what it is caching, why not make it that large and eliminate the device. {S16}
c) What are the differences between trap and an interrupt? What is the use of each
function. {S16}
d) Explain different types of services provided by operating system. {S17}
e) Explain the different hardware requirements for modern operating system. {S17}
f) Discuss the various services provided by operating system. Justify your answer by
giving real life example. {S18}
g) Write notes on any three.
i) Distributed system.
ii) Real time system.
iii) Batch system
iv) Hand held system
h) Discuss the various services provided by operating system. Justify your answer by giving
real life example. {S19}
i) Write short notes on:
i) Distributed system ii) Real time system iii) Batch system {S19}
j) What is mean by system call? How it is used by application program during execution?
{W16}
k) What is user and system view of operating system? {W16}
l) What are disadvantages of Batch processing OS. {W16}
m) Enlist and explain different events in OS? {W17}
n) Differentiate between Application software & system software? {W17}
o) Write short note on time sharing OS? {W17}
p) Explain different levels of Design & Implementation of OS. Give its object & typical
operation that OS perform at different levels. {W18}
q) Explain different types of system call in detail. {W18}
r) List and explain various services provided by operating system. {W19}
s) Explain with neat diagram the concept of system calls. List pointwise functions of
various system calls used. {W19}
OPERATING SYSTEM: UNIT 2

____SUMMER 16_____

3. a) Suppose a disk drive has 300 cylinder numbered 0 to 299. The drive is currently serving a
Request at cylinder 127. The queue of pending request in FIFO order is 76, 94, 99, 130, 187,213,
289, and 295.
Starting from the current head position, what is the total distance (in cylinder) that the disk Arm
moves to satisfy the entire pending request for each of the following disk scheduling Algorithm
FCFS, SSTF, SCAN, C-SCAN, LOOK, C-LOOK
b) What are the pieces of information associated with open file? Explain each of them.
4. a) Explain various directory structures in detail.
b) Explain different disk space allocation strategies.

_____SUMMER 17______

3. a) Explain contiguous and Index allocation methods.

b) Suppose that a disk drive has 5000 cylinders numbered from 0 to 4999. The drive is currently
serving a request at cylinder 143 and previous request was at cylinder 125. The queue of pending
request in FIFO is 86, 1470, 913, 1774, 948, 1509,1022, 1750,130 starting from the current head
position, what is the total distance that the disk arm moves to satisfy all the pending request for each
of the following disk scheduling algorithms
1) FCFS
2) SSTF
3) SCAN
4) C-SCAN
5) LOOK.
6) C-LOOK
4. a) Discuss the various file Access methods
b) What is the need of file system? Explain various operations associated with files. 7
c) Define file system. What are the various components of file system?

____SUMMER 18_____

3. a) Discuss various access methods for file with its advantages.

b) Explain linked allocation and indexed allocation strategies.
4. a) None of the disk scheduling disciplines, except FCFS, is truly fair (saturation may Occur)
i) Explain why this assertion is true.
ii) Explain why fairness is an important goal in a time sharing system.

______SUMMER 19_____

3. a) Explain contiguous and Index allocation methods.

b) Suppose that a disk drive has 5000 cylinders membered from 0 to 4999. The drive is
currently serving a request at cylinder 143 and previous request was at cylinder 125. The
queue of pending request in FIFO is 86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130
starting from the current head position, what is the total distance that the disk arm moves to
satisfy all the pending request for each of the following disk scheduling algorithms.

i) FCFS
ii) SSTF
iii) SCAN
iv) C-SCAN
v) LOOK
vi) C-LOOK
4. a) Discuss the various file Access methods.
b) What is the need of file system? Explain various operations associated with files.

_____WINTER 16____

3. a) Explain different operations performed on file?

b) Explain different disk space allocation method?
4. a) Suppose that disk drive has 5000 cylinders from 0 to 4999.

The drive is currently serving request at cylinder 143 and previous was at cylinder 125.

The pending request in FIFO is 86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130. Starting
From current position what is the total distance that disk arm moves to satisfy all the Pending
request for each of following disk scheduling algorithms?
1) FCFS
2) SSTF
3) SCAN
4) LOOK
5) C- SCAN
6) C- LOOK

b) Explain single level Directory structure?

____WINTER 17_____

3. a) Explain different types of files created in OS?

b) Explain different file access methods?

c) Write short note on contiguous allocation?
4. a) Explain various directory structures in operating system?

b) Explain different attributes of file?

____WINTER 18____

3. a) Explain various directory structure of operating system.

b) Explain following Disk Space allocation methods.

i) Contiguous Allocation (Dynamic Allocation)
ii) Index Allocation
iii) Linked allocation

4. a) Suppose that the head of a moving head disk with 5000 tracks numbered 0 to 4999 is
Currently serving a request at track 143 & has just finished a request at queue of request is
Kept in the FIFO order-86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130. What is the total
Number of head movements needed to satisfy these requests for the following disk
Scheduling algorithms-

i) FCFS
ii) SSTF
iii) SCAN
iv) LOOK.
b) Write short note on scheduling Queues?

____WINTER 19____

3. a) Define a file system? Explain various operations associated with files.

b) Explain different access methods for file.

4. a) Describe various scheme that are used for logical structuring of directories.

b) Suppose the head of moving head disk with 200 cylinders and is currently at track 60 if
the queue of a request is kept in order as 65, 170, 35, 120, 10, 140. What are the total head
movements to satisfy the request for the scheme?

i) SSTF
ii) C-SCAN
iii) FCFS
iv) SCAN
iv) LOOK
Operating system: UNIT:3

_______Summer 16______
1. A) Explain the long-term, short-term and medium term schedulers.
b) Differentiate between process and a thread by taking a suitable example.
c) What is PCB? Describe in brief.
2. a) Explain different CPU scheduling criteria’s.
b) Consider the following set of process with length of CPU burst time gives in millisecond.

Give Gantt chart and calculate the average waiting time for.
i) FCFS.
ii) SJF.
iii) Round Robin (Slice = 4 ms)
iv) Priority scheduling algorithm.

____SUMMER 17_____

3. a) Explain the concept of process control Block, with neat diagram.

b) Consider the following set of processes. Calculate the average waiting time and turnaround
time for following algorithms
1) FCFS
2) SJF
3) RR (time slice = 2)

4. a) Define Thread. Explain the various Multithreaded Models.

b) Draw the state transition diagram of process and Explain each state in detail. 4
c) What is scheduler? Explain different types of schedulers.

_____SUMMER 18_____
 5. a) What is context switch ? Give any one example where context switch occurs.
b) Explain schedulers, with appropriate diagram of scheduling queues and describe it
with all cases possible.
c) Give the benefits of using thread. Why multithreading model is more useful ? Justify
your answer with example.
6. a) Calculate average waiting time, average turn around time and average response
time

For a given situation. Assume time quantum of 2ms for Round Robin algorithm
Apply following cpu scheduling algorithms on it.
i) FCFS ii) SJF (with without preemption)
ii) Priority iv) Round Robin.
b) Explain Linux threads in brief.

_____SUMMER 19____

5. a) Define Thread. Explain the various Multithreaded Models.

b) Draw the state transition diagram of process and Explain each state in detail.
c) What is Scheduler? Explain different types of Schedulers.
6. a) Explain the concept of process control Block, with neat diagram.
b) Consider the following set of processes. Calculate the average Waiting time and turn
around time for following algorithms.
i) FCFS
ii) SJF
iii) RR (time slice-2)

_____WINTER 16______

5. a) Explain different state of process.

b) Write short note on PCB.
c) Explain in Detail inter Process Communication?
6. a) Explain the various multithreading model for thread?
b) Explain different CPU Scheduling algorithms?
_____WINTER 17_____

5. a) Write a short note on scheduling Queue?

b) Consider the following set of processes

Calculate waiting & turn around time for each algorithm.

i) FCFS
ii) SJF
iii) RR (Slice = 2).
6. a) Explain in detail interprocess communication? 8

b) Write short note on following. 6

i) Context switching. Ii) Process creation
ii) Process termination

______WINTER 18______

5. a) Explain in detail interprocess communication.

b) Write short note on following:
i) Context Switching
ii) Process Creation
iii) Process termination
c) What is CPU schedular?
6. a) Consider 5 processes
P , P , P , P , and P 1 2 3 4 5
With length of CPU burst time. Find out
Average waiting time & average turnaround time for following:
i) FCFS
ii) RR (Slice=2ms)
iii) SJF (Preemptive & non-preemptive)

b) What are the different scheduling criteria for selecting scheduling algorithm?
 _____WINTER 19______

5. a) Draw state transition diagram of a process. What do you mean by a process control
block
Explain it with neat diagram.
b) What are the different kinds of schedulers present in the system? Bring out the
relevance
of each of them.
a) Define thread. Explain various multi threading models for threads.
b) Consider following set of processes.

Calculate the average waiting time and turn Around time for each algorithm.
i) FCFS
ii) SJF
iii) RR (time slice = 3)
iv) Priority

____________________________________************___________________________
___
 UNIT 4
Q1.a) Write short notes on : (summer 16)
i) Belady's Anomaly. ii) Thrashing.
b) Consider the page reference string.
1234534167878978954592
Assume page frame size = 4, find out the algorithm having. Minimum page fault rate.
1}FIFO 2} LRU 3} Optimal.
Q2. a) Explain segmentation as a non contiguous memory allocation scheme. (summer 16)
b) What is physical address and logical address? How the mapping is done in between them?
Q3.a) What is fragmentation? Explain Internal fragmentation and External Fragmentation.
(summer 17)
b) Explain the hardware implementation of paging in detail with neat sketch.
Q4. a) What is Thrashing? What is the causes of thrashing? How can the system eliminates the
problem of thrashing? (summer 17)
b) Consider the following page reference string 1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5 for a memory
with 3 frames. How many page fault would occurs for the following page replacement
algorithms.
1) LRO
2) FIFO
3) Optimal replacement.
Q5. a) Explain the concept of address binding with diag. Also explain dynamic loading. (summer
18)
b) What is backing store? Swapping is an important concept used in case backing store
! Are you agree with the statement? Justify your answer.
c) Discuss the basic method used for implementing paging with example.
Q6. a) Explain how segmentation is achieved using hardware? (summer 18)
b) What is Thrashing ? Give an example where thrashing is occurred, while using
operating system.
c) Calculate how many page faults will occur for the following algorithms applied on
given reference string with three page frames.
1, 2, 3, 4, 5, 3, 4, 1, 6, 7, 8, 7, 8, 9, 7, 8, 9
i) FIFO
ii) Optimal Page Replacement
iii) LRU page replacement
Q7.a) What is fragmentation? Explain Internal fragmentation and External fragmentation.
(summer19)
b) Explain the hardware implementation of paging in detail with neat sketch.
Q8. a) Write short notes on: (summer 19)
i) Thrashing ii) Garbage collection
b) Consider the following page reference string 1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5 for a memory
with 3 frames. How many page faults would occur for the following page replacement
algorithms.
i) LRU ii) FIFO
iii) Optimal replacement
Q9. a) What is address binding? Explain Various types of binding? (winter 16)
b) Consider following page reference string 4 3 2 1 4 3 5 4 3 1 5
Assume frame size = 3. How many page fault would occur for FIFO, optimal & LRU
algorithm?
10. a) What is page fault? Explain different steps to handle page fault. (winter 16)
b) Explain the different page table structures?
Q11. a) What is address binding? Explain various types of binding. (winter 17)
b) Write short notes on :
i) Thrashing ii) Garbage collection.
Q12. a) What is memory fragmentation? Differentiate between Internal & External
Fragmentation? (winter 17)
b) Explain paging. How it is implemented. What hardware is required?
Q13.a) Describe the following. (winter 19)
i) Memory protection.
ii) Internal and External fragmentation.
iii) Paging and segmentation.
b) Explain swapping, dynamic loading and overlays.
Q14. a) With neat diagram explain the concept of demand paging. (winter 19)
b) Explain optimal page replacement algorithm with an example.
c) Consider the following page reference string.
1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5 for a memory with 3 frames. How many page fault and PFR
would occur for following –
1}FIFO page replacement. 2}LRU page replacement.
Q15.Explain paging and its implementation. What hardware is required for paging. (winter 18)
b) Consider the following segment table.

What are the physical addresses for the following logical addresses?
i) 0, 430 ii) 1, 10
iii) 1, 11 iv) 2, 500
v) 3, 400
Q16. a) Explain the need of virtual memory and how it is implemented. (winter 18)
b) Consider following page reference string-
4121541215
How many page fault would occur for the following page replacement algorithms
assuming 3 frames?
i) FIFO ii) LRU
iii) Optimal
Q17. a) Discuss the paging technique for mapping the virtual address with physical address with
neat sketch and example. (summer 16)
b) Define the following terms.
a) Thrashing b) Overlays.
Q18. a) Consider the page reference string. (summer 16)
1, 2, 3, 4, 5, 3, 4, 1, 6, 7, 8, 7, 8, 7, 8, 9, 7, 8, 9, 5, 4, 5, 9.
Assume page frame size = 3 Find out the algorithms having minimum page fault rate.
i) FIFO ii) LRU iii) Optimal

b) Discuss the disk space management concept.

Q19&20 (winter 15)

Q21&22 (winter 150

s
 UNIT 5
[SUMMER 16]
1. Explain the following.
i) Access matrix. ii) Capability list. iii) Language based protection. [9]

2. Explain deadlock recovery. [4]

[SUMMER 16]

3.

4. What is Dead lock? Explain 4 conditions of deadlock Also explain how deadlocks can be
prevented. [7]

[SUMMER 17]
5. Write short noes on issues involved in deadlock recovery? [5]

6. Write and explain Banker’s algorithm for deadlock avoidance. [7]

[SUMMER 17]
7. What are the goals of protection in a computer system? [3]

8. Describe the deadlock preventions methods. [7]

[SUMMER 18]

9.
[10]
[SUMMER 18]
10. Explain the following:
i) Goal of protection and security.
ii) Access list and capability list.
iii) Schemes for implementing revocation for capability.
iv) Advantages of encrypting data in computer system.

11. Define Deadlock. What are the necessary condition for occurrence of deadlock.
[4]

[SUMMER 19]

12.
[10]

13. Explain the access matrix in details along with its implementation.
[7]

[SUMMER 19]
14. Describe Resource allocation graph. Prove that if a graph contain a cycle still there is no
deadlock. [7]

15. Deadlocks can be described more precisely in terms of a directed graph. Justify your answer
with example. [6]

16. Explain how deadlock can be prevented. [7]

17.
[8]

18. Explain the following.

i) Deadlock system model. [4]
ii) Resource allocation graph. [4]
iii) Deadlock prevention. [5]

19. What are different characteristic of deadlock? [6]

20. Write short note on Resource allocation graph? [7]

21. How to Handle Deadlock? [3]

22. How can you prevent deadlock by preventing circular wait condition?
[3]

23. Define Deadlock. To arise deadlock in system what are necessary conditions it should meet?
[7]

24. Write a short note on access matrix implementation. [6]

25.

26. What are the various condition for Deadlock prevention. [5]

27. What is An Access Matrix? Describe various methods to implement an Access matrix.
[7]

28. Explain the various methods to break a deadlock and recover from it.
[6]
11. a) Consider the following snapshot of a system: SUMMER 16

Allocation MAX
ABCDABCD
P1 0 0 1 4 P1 0 6 5 6
P2 0 6 3 2 P2 0 6 5 2
P3 0 0 1 2 P3 0 0 1 2
P4 1 0 0 0 P4 1 7 5 0
P5 1 3 5 4 P5 2 3 5 6
Available
ABCD
1620

Answer the following for Banker's algorithm:

i) What is the content of matrix Need? ii) Is the system in safe state.
iii) If the request from P1 arrives for (0,5,2,0), can request be granted immediately?

10marks

b) Explain Resource Allocation Graph (RAG) with an example. 4marks

OR

12. Explain the following.

i) Goal of production and security. ii) Access list and capability list.
iii) Schemes for implementing revocation for capability.
iv) Advantages of encrypting data in computer system.

14marks

SUMMER 17
11. a) Define Deadlock. What are the necessary condition for occurrence of deadlock. 4marks

NKT/KS/17/7295 3 P.T.O
b) Solve the following using Banker's Algorithm and find out whether resultant system state
is safe or not 10 marks

Allocation Max Available

ABCABCABC
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
i) Find out if system state is safe, if safe find out safe sequence.
ii) If P1 makes a request – P1 (1, 0, 2) is the resulting state safe?
iii) If P4 makes a request – P4 (3, 3, 0), can it be granted? Solve

OR

12. a) Explain the access matrix in details along with its Implementation. 7marks
b) Describe Resource allocation graph. Prove that if a graph contain a cycle still there is no
deadlock.7 marks

SUMMER 18
11. a) Deadlocks can be described more precisely in terms of a directed graph. Justify your

answer with example. 6marks

b) Explain how deadlock can be prevented. 7

OR
SUMMER 19 / WINTER 16
11. a) Explain Banker's algorithm in detail. 7 marks
b) What is the difference between ACCESS list & CAPABILITY List? 6marks

OR

12 a) Explain the following.

i) Deadlock system model. 4m

ii) Resource allocation graph. 4m
iii) Deadlock prevention. 5m

WINTER 17
WINTER 18

WINTER 19