D 060001T305122002 Pages: 3

Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
Fifth Semester B.Tech Degree Examination (Regular and Supplementary), December 2020

Course Code: IT305
Course Name: OPERATING SYSTEMS

Max. Marks: 100 Duration: 3 Hours
PARTA
Answer any two full questions, each carries 15 marks. Marks
1 a) Explain three main purposes of Operating Systems. (3)
b) Explain System call with an Example. (5)
c) What is Process Control Block? Explain the contents of PCB. (7)

2 a) How does the distinction between kernel mode and user mode function as an (5)
elementary form of protection system? Explain with diagram.
b) What are the two types of real time operating system? (3)
c) Explain the effect of time quantum in round robin scheduling with required (7)
diagrams.
3 a) Consider the following set of process (8)
Process ime Burst Time
Pl
P2
P3

74

i) Draw the Gantt chart to show the execution time using FCFS and round
robin scheduling with time quantum-4

ii) Calculate waiting time and turn around time of each of the process for
FCFS and round robin. Also calculate the average waiting time and
average turn around time for each of the scheduling algorithm.

b) Explain the layered approach to system design. What are its advantage and (7)
disadvantage?
PART 13
Answer any two full questions, each carries 15 marks.

4 a) Differentiate cooperative process and independent process. (3)

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