Rajiv Gandhi Proudyogiki Vishwavidyalaya 2007-2nd Sem M.C.A Computer Aplications .(ester) , e, -university question paper

MCA-201
M.C.A.(Second Semester) EXAMINATION, June,2007
OPERATING SYSTEM
(MCA-201)
Time : 3 Hours
Maximum Marks : 100
Minimum Pass Marks : 40

Note : Attempt any 2 parts from every ques.. All ques. carry equal marks.

1.(a) explain about various kinds of operating system with regard to the subsequent aspects :
(i) Processor Scheduling
(ii) Memory Management
(iii)I/O Management
(iv) File Management
(b) explain a System Programmer's view of process. define the differences among short-term,
medium term and long-term scheduling.
(c) consider the ahead set of process, with the length of CPU burst time provided in milliseconds:
Process Arrival Time Burst Time
P1 0 8
P2 one 4
P3 two 9
P4 three 5
Draw the Gantt Chart and compute avg. waiting time for :
(i) FCFS
(ii) Pre-emptive SJF scheduling

2.(a) discuss the differences ranging from logical and physical addreses. Consider a logical-address
space of 8 pages of 1024 words each, mapped onto a physical recovery of 32 frames :
(i) How many bits are in the logical address ?
(ii) How many bits are in the physical address ?
(b) How many page faults occur for the subsequent reference string, using 4 page frames ?
1,2,3,4,5,3,4,1,6,7,8,7,8,9,7,8,9,5,4,2
(i) FIFO replacement
(ii) Optimal replacement
(iii) LRU replacement
(c) What is the reason of thrashing ? How does the system detect thrashing ? Once it detects
thrashing, what can the system do to eliminate this issue ?

3.(a) What do you mean by Mutual Exclusion ? explain Dining Philosophers issue. Also provide
solution to it.
(b) Consider the subsequent snapshot of a system :
Allocation Max. Available
A B C A B C A B C
P0 0 one 0 seven five three three three 2
P1 two 0 0 three two two
P2 three 0 two nine 0 two
P3 two one one two two two
P4 0 0 two four three 3
(i) What is the content of the Matrix Need ?
(ii) Is the system a safe state ?
(iii) If a request arrives for(1,0,2) can the request be granted immediately ?
(c) discuss in detail the Bankers algorithm used for deadlock avoidance. Also discuss
the saftey algorithm used to check whether the system is in a safe state or not.

4.(a) explain different operations performed on a file. Consider a file system where a
file can be deleted and its disk space reclaimed while links to that file still
exist. What issues may occur if a new file is created in the identical storage area
or with the identical absolute path name ? How can these issues be avoided ?
(b) discuss security threats protection intruders with examples.
(c) A disk queue with 200 tracks, numbered 0 to 199 with requests for I/O to blocks
on cylinders in the order :
98, 183, 37, 122, 14, 124, 65, 67
If the disk head is initially at cylinder 53, what is the total distance that
the disk arm moves to satisfy all the pending requests for every of the disk
scheduling algorithms ?
(i) FCFS
(ii) SSTF
(iii) LOOK
(iv) C-SCAN

5.(a) What is Multithreading ? explain the differences ranging from user-level threads and
kernel-level threads.
(b) Why is performance monitoring and valuation needed for distributed approach ?
explain valuation techniques in brief.
(c) elaborate the benefits of a Distributed File System(DFS) in a centralized system ?
Or
Compare Unix and windows system.

Earning:   Approval pending.