CS-63 : Introduction To System Software-December,2007

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BACHELOR IN COMPUTER

APPLICATIONS

Term-End Examination

December, 2OO7

CS-63 : INTRODUCTION TO SYSTEM

SOFTWARE

Time : 2 hours Maximum Marks ; 60

l. (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 (5)

mappings in a paging system and a segmented

system.

5.

(a)with the help of any GUl-based operating system, (4)

explain the major components of its environment.

(b) Explain the following concepts : (6)

(i) Symbol Table

(ii) Case Tools

(iii) 4 GLs