IGNOU ‘Introduction to System Software’ Paper 1

CS – 63: INTRODUCTION TO SYSTEM SOFTWARE
Time: 2 hours
Maximum Marks: 60

Note: Question number 1 is compulsory. Answer any three questions from the rest.

1. (a) Explain the syntax analysis phase of a compiler design. Write the CFG for an arithmetic expression and generate a parse tree for the expression a + b * c / d - e * f (8)

(b) Consider the following set of processes arrived at the sametime: (8)
Process CPU Time
P 1 5
P 2 10
P 3 8
P 4 4

Draw the Gantt chart and calculate the average turnaround time and average waiting time for

(i) SJF
(ii) FCFS scheduling.

(c) Write an algorithm and draw the corresponding flowchart for generating the fibonacci series.(8)

(d) Write a shell program to encrypt any text file using the following table. (7)

Character to be replaced with
a P
e q
i r
o s
u t
s o

other characters Remains unchanged
0 to 9 Replace with 9 to 0

2. (a) Give necessary conditions for deadlock occurrence. Explain with an example and draw the resource allocation graph to represent a deadlock. (5)

(b) Explain the concept of dynamic partition memory management.What are the advantages of dynamic partition over fixed-size partition of memory? (5)

3. (a) Write UNIX commands for:(7×5=5)

(i) to find the no. of users logged on the system.
(ii) to copy file to another file2 in the same directory.
(iii) to stop the background process.
(iv) to create a file named “cities”.
(v) to terminate a login session.

(b) What is a 4GL? Give two examples of 4GL. Discuss the relative advantages and disadvantages of 4GLs in software development. (5)

4. (a) Give suitable example to illustrate both first fit and best fit strategies of disk allocation (5)

(b) Explain the address mapping procedure in a paging system,with the help of a diagram. (5)

5. (a) Create a shell program which will display the following menu and then perform the desired function based on the user’s choice: (5)

Functions’ Menu:

1. PRINT sorted list of users.
2. Change environment variables.
3. To change the permission mode for any file.

(b) Draw a diagram for the structure of an editor and explain. (5)