SAMPLE QUESTION PAPER OPERATING SYSTEM
OPERATING SYSTEMS
(TCS-601)
Time: 3 Hours Max. Marks: 100
Note:Attempt
All Questions. All questions carry equal marks.
Question 1 Attempt any four parts of the
following: [5 X 4
= 20]
(A) What is layered
approach of operating system Design? Enumerate
its
advantages and disadvantages [5]
(b) Explain the
following terms:-
(i) Multiprogramming
(ii) Spooling
(iii) Multitasking
[2+1+2]
(c) Enumerate the basic
functions of operating system and explain in brief. [5]
(d) List five services
provided by an operating system. Explain how each
of them provides convenience to the users. [5]
(e) What is the purpose
of system calls or application programmer interface
(API)?
Enumerate five system calls used in operating system. [5]
(f)
Why is it expensive to switch between
processes? Is it less expensive
to
switch between threads? Justify your answer. [5]
Question 2 Attempt any four parts of the
following: [5X 4=
20]
(a)
What is semaphore? How it satisfies the
requirement of critical section
solution?
[5]
(b)
Draw the state diagram of a process and
label various transitions.
Explain
the need of process suspension. [5]
(c)
Describe the reader’s and writer’s problem.
(d)
Wait for graph is a necessary and sufficient
condition for the occurrence of
deadlock. Justify
your answer.
[5]
(e)
Define the following terms: [1+1+1+1+1]
(i)
Dispatcher
(ii)
Dispatch latency
(iii)
Scheduling
(iv)
Swapping
(v)
Context switching
(f)
Explain with respect to IPC [2.5+2.5]
(i)
Synchronous and asynchronous
(ii)
Need of buffering and its implementation
Question
3 Attempt any two parts of the
following: [10
X 2 = 20]
(a) Suppose
that the following processes arrive for executions at the
times indicated:- [5+5]
Process
|
Arrival
Time
|
Burst
Time
|
P1
|
0.0
|
8
|
P2
|
0.4
|
4
|
P3
|
1.0
|
1
|
(i)
What is the average turnaround and waiting
time for these processes
with the FCFS
scheduling algorithm?
(ii)
What is the average turnaround and waiting
time for these processes
with the preemptive
SJF scheduling algorithm?
(b) Explain advantages and disadvantages of each
scheduling algorithm
with respect to CPU scheduling.
[10]
(c) Describe
the Banker’s algorithm. Consider a system with five processes
And three resources
and at time T0 , the following snapshot of the system
has been taken:- [5+5]
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
Show that the system is in safe state. Find the sequence which satisfies
the safety criteria
Question
4 Attempt
any
two parts of the following: [10
X 2 = 20]
(a) Describe
the paging scheme of memory management with reference to the
Hardware required
to support the system. [10]
(b) Explain
the difference between external and internal fragmentations. If
Memory partitions
of 100K, 500K, 200k, 300k and 600k (in order) are
given, how would
each of the first-fit, best-fit and worst-fit algorithms
place processes of
212K, 417K, 112K, and 426K(in order) ? Which algorithm makes the most efficient
use of memory? [10]
(c)
(i) What is
the cause of thrashing? What steps are taken by the system to eliminate this
problem? [5]
(ii) How many
page-faults would occur for the following string, for four page frames using
LRU algorithm:- [5]
1, 2, 3, 4, 5, 3, 4, 1, 6, 7, 8, 7, 8, 9, 7, 8, 9, 5, 4, 5, 4, 2
Question
5 Attempt any two parts of the
following: [10
X 2 = 20]
(a)
A disk with 100 cylinders, numbers 0 to
999, compute the number of tracks
the disk arm must
move to satisfy all the request in the disk queue. Assume
the last request
serviced was at track 345 and head is moving towards track 0. The queue is FIFO
order contains request for the following tracks:
123,
874, 692, 475,
105, 376.
Perform
the computation for the following scheduling algorithms:
(i) FIFO
[4+3+3]
(ii) SSTF
(iii) SCAN
(b)
Discuss the Contiguous, Linked, Index and
Multilevel Indexing file
allocation schemes.
Which allocation scheme will minimize the amount
of space required
in directory structure and why? [7+3]
(c)
Discuss the following with respect to I/O
System : [5+5]
(i)
Basic functions
(ii)
Block and character devices
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