Mumbai University Previous year question papers Operating System for Computational Devices June 2010

Mumbai University Previous year question papers

V Sem IT Examination June 2010

Operating System for Computational Devices


(1) Question No.1 is compulsory.

(2) Attempt any four questions out of remaining six questions.

(3) Assume suitable data wherever required but justify them.

(4) All questions carry equal marks.


(5) Answer to each new question to be started on a fresh page.

(6) Figures to the right indicate full marks.


1. (a) What are the various real-time CPU scheduling algorithms. Explain each one in brief.

(b) What are requirements of mutual exclusion? Explain Peterson’s algorithm for mutual exclusion.


2. (a) What are two differences between user-level threads and Kernel-level threads? Under what circumstances is one type better than the other?

(b) Consider the following page reference string:- 10


How many page faults would occur for the following replacement algorithms assuming I”‘” one, two, three, four, five, six or seven frames?

LRU Replacement

FIFO Replacement

Optimal Replacement.


3.(a) How does DMA increase system concurrency? How does it complicate hardware design?

(b) How do caches help improve performance? Why do systems not use more or larger caches if they are so useful?


4. (a) What are the various disk-scheduling algorithms. Explain each one in brief. 10

(b) Consider the following segment table :- 10

Segment Base Length

0 219 600

1 1 2300 14

2 90 100

3 1327 580

4 1952 96

What are the physical addresses for the following logical addresses?

(i) 0,430, (ii) 1,10, (iii) 2,500, (iv) 3,400, (v) 4,112.


5.(a) What are the four conditions that create deadlock? Explain deadlock prevention and avoidance techniques.


(b) Given five memory partitions of 100 kB, 500 kB, 200 kB, 300 kB, and 600kB (in order), how would the first-fit, best-fit, and worst-fit algorithms place processes of212 kB, 417 kB, 112 kB, and 426 kB (in order)? Which algorithm makes the most efficient use of memory?


6. (a) What are the various buffering techniques? Explain each one in detail. 10

(b) Explain file allocation methods in details. 10


7. Write a short notes on any four of the following :- 20

(a) Monolithic Vs. Micro Kernels (d) NOS Vs. DOS ~

(b) Comparison of any two RTOS (e) Race Condition ~~

(c) V x Works 5.X (f) Inodes. I:c~~

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