CS-63 QUESTION PAPERS » DEC 2007 CS-63 QUESTION PAPER

IGNOU BCA CS-63 INTRODUCTION TO SYSTEM SOFTWARE - DECEMBER 2007 QUESTION PAPER

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BACHELOR IN COMPUTER APPLICATIONS
Term-End Examination
December, 2007
CS-63: INTRODUCTION TO SYSTEM SOFTWARE

Time : 2 Hours

Max. Marks : 60

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Note : Question one is compulsory. Answer any three from the rest.

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1. (a) Write regular expressions for I
(i) A set of strings including {d, abd, cd, abcd}
(ii) A set of strings x’s, y’s and z’s. For example {xxx, xxy, xxz …zzz}
(b) Write an algorithm that accepts as input a decimal number and converts it into octal representation and also draw the corresponding flow chart for the same.(7)

(c) Consider the following set of processes which arrive in the ready queue at the same time : Process CPU time
P1 8
P2 T2
P3 7
P4 9
P5 4
Consider the following scheduling algorithms ‘F’CFS, SJF and Round robin (quantum : 2) find the average turnaround.time.
(ii) What is waiting time of each process for each of the above scheduling algorithms ? Also, find the average waiting time I
(d) Write a shell program to find whether a given number is an Avogadro number or not 7 (e.s. 153 is Avogadro no. as 153 = 13 + 53 + g3)

2. (a) What are the important tasks performed during : (6)

i) Lexical analysis
ii) Syntax analysis
ii) Semantic analysis
(b) What is the usefulness of context free grammar? Explain with an example. (4)

3. (a) Describe how fixed records L/O and variable length (5)
(b) what are the main advantages of distributed operating systems ? How are the fire system and the protection supported in distributed operating systems ?

4. (a) write UNIX commands for the following : (5)
(i) To change the password for a given user.
(ii) concatenate the contents of 3 files into a single file.
(iii) To run a particular command at the given time.
(iv) To display hard disk space used.
(v) To display the lines that do not include the given string.
(b) Illustrate and discuss with a diagram, the address mappings in a paging system and a segmented system.(5)

5. (a)with the help of any GUl-based operating system, explain the major components of its environment.(4)
(b) Explain the following concepts : (6)
(i) Symbol Table
(ii) Case Tools
(iii) 4 GLs