Test Papers / Previous Question Papers of IGNOU CS02 Introduction to Software December 1997

PGDCA / MCA (I Yr) / BCA
Term-End Examination

December, 1997

CS02 : Introduction to Software

Time: 2 hours
Maximum Marks: 60

1. (a) Write a regular grammar for the following :
(i) Set of strings of a' s, b' s and c' s
For example (aaa, aab,……… ccc)
(ii) Looping statements of Pascal.
(b) Explain which of the following are reasonable long term scheduling algorithms and which are reasonable short term scheduling algorithms.
First Come-First Served.
Round Robin
Shortest Job First
Highest Priority First
Longest Process First
(c) Write an algorithm/program recursively to find out whether a word/sentence is palindrome or not?
(d) Write UNIX commands for the following :
(i) To find out how many super users there are in installation.
(ii) Find out all lines in a file with words longer than 8 letters, assuming that words are separated by spaces except at the beginning or and of line.

2. (a) What are conditions that characterize deadlock? Explain the occurrence and avoidance of deadlock graphically among 3 processes and 3 resources.
(b) List four strategies the operating system designers can adopt vis-à-vis the problem of deadlock.

3. (a) What is meant by pre-emptive scheduling? How does it affect system performance in comparison to non-pre-emptive scheduling?
(b) Discuss various scheduling objectives and their meanings. Show how different objectives can at times be contradictory.

6. (a) Discuss H/W support for mutual exclusion.
(b) Discuss mechanisms for structured form of inter-process communication and synchronization.