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Dec 14, 2013 (3 years and 7 months ago)

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SET
-
1

II B. Tech II Semester Regular Examinations, April/May 2009

OPERATING SYSTEMS

( Information Technology )

Time: 3 hours Max Marks: 80

Answer Any FIVE Questions

All Questions carry
equal marks

1. (a)What are the various objectives and functions of Operating
Systems? [12]

(b)Briefly explain system calls [4]

2. (a) Describe various operations on threads.

(b) Discuss about threads synchronization.

(c) Write about Kernel level threads. [
6+5+5]

3. (a) What is a semaphore? What are the various operations defined
on it?

(b) What is the difference between weak semaphore and strong
semaphore?

Explain. [8+8]

4. Explain paging scheme for memory management, discuss the
paging

hardware and paging
model. [16]

5. (a) Three processes share 4 resource units that can be reserved
and reused

only one at a time. Each process needs a maximum of 2 units. Show
that

a deadlock cannot occur.

(b) N processes share M resource units that can be reserved and
released

only one at a time. The maximum need of each process does not
exceed

M and the sum of all maximum needs is less than M + N. Show that a

dead lock cannot occur. [8+8]

6. (a) Explain file system software architecture.

(b) What are the important crit
eria in choosing a file organization?

(c) Explain the file and sequential file organization. [6+5+5]

7. Write short notes on,

(a) Random disk scheduling

(b) Priority disk scheduling

(c) Disk cache [5+5+6]

8. Define Access Matrix. How can it be used for pro
tection? Explain
some



implementation schemes of it. [16]


SET
-

2

II B. Tech II Semester Regular Examinations, April/May 2009

OPERATING SYSTEMS

( Information Technology )

Time: 3 hours Max Marks: 80

Answer Any FIVE Questions

All Questions carry equal marks

1. Explain the following:

(a) Multitasking

(b) Multithreading

(c) Multiprocessing

(d) Time sharing. [4+4+4+4]

2.(a) Explain the role of process control block in OS.

(b) Explain the process state transmission diagram with examples.
[8+8]

3. (a) Define and
Explain critical section problem. [6+10]

(b) Explain about protection technique of critical section in LINUX with
neat

diagram.

4. (a) Write short note on page table structure. [8]

(b) Compare global and local page replacement algorithms. What are
the

adva
ntages of each? [8]

5. (a) Write Banker’s algorithm for deadlock avoidance.

(b) Define DMA data transfer. Briefly explain all the steps in DMA
transfer

with neat examples. [8+8]

6. (a) Explain file system software architecture.

(b) Explain the functions of

a file management system with a
diagram.[8+8]

7.(a) Explain various disk performance parameters

(b) What do the various RAID levels refer to? Explain [8+8]

8. Write short notes on

(a) Trojan horse

(b) Trap door

(c) Logic bomb

(d) Viruses [4+4+4+4]


SET
-

3



II B. Tech II Semester Regular Examinations, April/May 2009

OPERATING SYSTEMS

( Information Technology )

Time: 3 hours Max Marks: 80

Answer Any FIVE Questions

All Questions carry equal marks

1. (a) Discuss the Operating System design hierarchy with an
ex
ample.

(b) Explain the applications of Unix Operating System. [8+8]

2. (a) What resources are typically shared by all of the threads of a
process?[8]

(b) Define process preemption. [8]

3. (a) Define monitor. What are its characteristics? [8]

(b) Briefly
explain the monitors solution to dining philosopher’s
problem[8]

4. (a) Write short note on paging. [6]

(b) Explain segmentation scheme for memory management. Give the

Segmentation hardware. [10]

5. (a) Explain about deadlock avoidance [8+8]

(b) Explain al
l the strategies involved in deadlock detection and how it
is

recovered.

6. (a) What do you understand by a file directory?

(b) Explain briefly the information elements of a file directory.

(c) Explain what is tree
-
structured directory? [5+5+6]

7. Suppose
the head of a moving
-

head disk with 200 tracks,
numbered 0 to

199, is currently serving a request at track 143 and has just finished a
request

at track 125.If the queue of requests is kept in FIFO order: 86, 147,
91, 177,

94, 150, 102, 175,130. What is th
e total head movement to satisfy
these

requests for the following disk scheduling algorithms.

(a) FCFS (b) Random

(c) PRI (d) SCAN

(e) SSTF (f) C
-

SCAN [16]

8. Define Access Matrix. How can it be used for protection? Explain
some

implementation schemes of
it. [16]

SET
-

4



Code No: 3221206

II B. Tech II Semester Regular Examinations, April/May 2009

OPERATING SYSTEMS

( Information Technology )

Time: 3 hours Max Marks: 80

Answer Any FIVE Questions

All Questions carry equal marks

1. (a)Justofy the following
statements.

(i) OS can be viewed as a resource allocator

(ii) OS as a control program. [8]

(b)List the major activities of operating system with regard to process

management ,secondary storage management. [8]

2. Briefly explain any four CPU Scheduling algo
rithms with neat
examples.[16]

3. (a) Write the program for mutual exclusion using semaphores.

(b) Explain about infinite buffer producer/consumer problem for
concurrent

processing which uses Binary Semaphores. [8+8]

4. Consider a memory management system
with demand paging.
There are

three processes P1, P2, P3 which have one page of private memory
each.

Moreover P1and P2 are sharing an array A which fits entirely into one

memory page. Similarly,P2 and P3 are sharing an array B, which fits
into a

memory pag
e.

(a) Let all the data for the processes be located into physical memory.
Draw

a possible memory allocation diagram, give the page tables for the
three

processes.

(b) Assume that process P1 gets swapped out of memory entirely.
How are

the page tables chan
ging.

(c) Assume that process P1 gets swapped back into memory. Give
the page

tables in this situation. [5+5+6]

5. What is deadlock avoidance? Expalin process initiation denial and
resource

allocation denial in detail with an example. [16]

6. (a) Explain w
hat is tree
-
structured directory.



(b) Describe various file allocation methods. [8+8]

7. (a) Describe various disk scheduling algorithms

(b) Briefly explain ,

(i) Disk formatting

(ii) Boot Block

(iii) Bad Blocks [8+8]

8. Write short notes on

(a) Trojan
horse

(b) Trap door

(c) Logic bomb

(d) Viruses [4+4+4+4]