2007 Rajiv Gandhi Proudyogiki Vishwavidyalaya(Technical University) Computer M.C.A M.C.A.(Second Semester) EXAMINATION, June,2007 Question paper
MCA-201
M.C.A.(Second Semester) EXAMINATION, June,2007
OPERATING SYSTEM
(MCA-201)
Time : Three Hours
Maximum Marks : 100
Minimum Pass Marks : 40
Note : Attempt any two parts from each question. All questions carry equal marks.
1.(a) Discuss about different types of operating system with regard to the following aspects :
(i) Processor Scheduling
(ii) Memory Management
(iii)I/O Management
(iv) File Management
(b) Discuss a System Programmer's view of process. Describe 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 given in milliseconds:
Process Arrival Time Burst Time
P1 0 8
P2 1 4
P3 2 9
P4 3 5
Draw the Gantt Chart and calculate average waiting time for :
(i) FCFS
(ii) Pre-emptive SJF scheduling
2.(a) Explain the differences between logical and physical addreses. Consider a logical-address
space of eight 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 following reference string, using four 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 cause of thrashing ? How does the system detect thrashing ? Once it detects
thrashing, what can the system do to eliminate this problem ?
3.(a) What do you mean by Mutual Exclusion ? Discuss Dining Philosophers problem. Also give
solution to it.
(b) Consider the following snapshot of a system :
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
(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) Explain in detail the Bankers algorithm used for deadlock avoidance. Also explain
the saftey algorithm used to check whether the system is in a safe state or not.
4.(a) Discuss various 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 problems may occur if a new file is created in the same storage area
or with the same absolute path name ? How can these problems be avoided ?
(b) Explain 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 each of the disk
scheduling algorithms ?
(i) FCFS
(ii) SSTF
(iii) LOOK
(iv) C-SCAN
5.(a) What is Multithreading ? Discuss the differences between user-level threads and
kernel-level threads.
(b) Why is performance monitoring and evaluation needed for distributed approach ?
Discuss evaluation techniques in brief.
(c) What are the benefits of a Distributed File System(DFS) in a centralized system ?
Or
Compare Unix and windows system.
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