Printed Pages : 3
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NCS401
(Following Paper ID and Roll No. to be filled in yourAnswer Book)
Roll No.
B. Tech. (sEM.
rv)
THEORY EXAMINATION, 2A:445 OPERATING SYSTEM
Time : 3 Hours]
I
questions:
Attempt any four [5x4:20) Describe the differences between symmetric and
(a) (b) (c) (d) G) (0
2
[Total Marks : 100
asymmetric multiprocessing. Discuss various operating system components.
What are the differences between shell and kernel? Explain layered structure of an operating system. Also explain advantages and disadvantages ofthe layered approach to system design. What is spooling ? Explain the principle of concurrency.
Attempt any two questions:
(a)
{10x2:291 What do you understand by critical section? Discuss bakery algorithm. Also show how it satisfies the requirements of a mechanism to control access to oritical section.
1104091
I Contd...
(b) (c)
Explain the following terms briefly:
G) G)
Dekkels Solution BusyWaiting
A barber shop consists of a waiting room with n chairs and a barber room with one barber chair. If there are no customers to be served, the'barber goes to sleep. If a customer enters the barbershop and all chairs are occupied, then the customer leaves the shop. If the barber is busy but chairs are availablq then the customer sits in one of the free chairs. If the barber is asleep, the customer wakes up the barber. Write an algorithm for the above synchronization problem using semaphores.
Attempt any two questions:
(a)
Explain the following scheduling algorithms
G) (i) O)
IAx2:2A)
Multilevel feedback queue scheduling
Multiprocesor Scheduling
Describe Banker's algorithm for deadlock avoidance. Consider a system with three process and three
resources. The snapshot of a system at time
to is
given
below: PROCESSES
ALLOCAI A
c
Pn
2
J
3
6
I
PI
2
0
5
4
3
t
Pr
I
2
4
3
4
4
G) r104091
MAX C
B 2
A
B
AVAILABLE B c
A 7
7
l0
Is the current allocation in safe state? I Contd...
(i)
(c)
Would the following requests be granted in the current state ? Process p, requests (1,0,0) Process p, requests (1,0,0) What is a thread? How thread is different from a process? What resources are used when a thread is
(a) , (b)
created?
Attempt any two
(a)
l|0x2:2g1
On a system using paging and segmentatioq the virtual address space consists ofup to 16 segments where each segment can be up to 2t6 bytes long. The hardware pages each segment into 512 byte pages. How many bits in the virtual address specify the following?
(a) (b) (c) (d)
(b) (c)
questions
Segment Number
Page Number
Offset within page Entire virtual address Explain segmentation with diagram. How many page faults would occur for the following reference string for four page frames using LRU and FIFO algorithms: 1,2 13,4,5,5,3,4, 1,6,7,9,7,9,9,7,9,9,5,4,5,4,2
questions:
Attempt any two U0x2:2g1 Discuss the following terms Access Matrix. Boot Blocks, Describe schemes for defining logical structure of
(a) (b) (c)
1r040el
0 G)
directory. Discuss disk scheduling algorithms with example.
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