Operating Systems 2018 Question Paper — Government College of Enginee…

The 2018 Operating Systems previous year question paper (Government College of Engineering and Technology, Jammu), with every question and its marks.

Instructions

There are 8 questions of 20 marks each.
Questions Nos. 1 to 4 are from section A.
Questions Nos. 5 to 8 are from section B.
Examinees are required to attempt 5 questions selecting at least two questions from each section.

Q1. Write a descriptive note on Operating System services and interfaces. [20 marks]
Q2. (a) Explain the various scheduling criteria used for comparing scheduling algorithms. (10) (b) What are scheduling queues, schedulers and context switch in process scheduling ? (10) [20 marks]
Q3. Suppose that the following processes arrive for execution at the times indicated. Each process will run for the amount of time listed : 10+10 | Process | Arrival Time | Burst Time | | :---: | :---: | :---: | | P1 | 0.0 | 8 | | P2 | 0.4 | 4 | | P3 | 1.0 | 1 | (a) What is the average turnaround time for these processes with the FCFS scheduling algorithm ? (b) What is the average trunaround time for these processes with the SJF scheduling algorithm? [20 marks]
Q4. Discuss semaphores and how are they used to synchronize processes ? [20 marks]

Q5. (a) Explain the fragmentation issue in memory allocation. (15) (b) Write a brief note on cache memory. (5) [20 marks]
Q6. What is a page replacement ? Explain any two page replacement algorithms. [20 marks]
Q7. (a) What is a deadlock ? How can occurrence of a deadlock be prevented ? (15) (b) Calculate content of the matrix need (use Banker's Algo.) for the following system : 5 | | Allocation | Max | Available | | :---: | :---: | :---: | :---: | | | A B C D | A B C D | A B C D | | $P_0$ | 0 0 1 2 | 0 0 1 2 | 1 5 2 0 | | $P_1$ | 1 0 0 0 | 1 7 5 0 | | | $P_2$ | 1 3 5 4 | 2 3 5 6 | | | $P_3$ | 0 6 3 2 | 0 6 5 2 | | | $P_4$ | 0 0 1 4 | 0 6 5 6 | | [20 marks]
Q8. Write notes on any four of the following : 5+5+5+5 (i) RAID Level 6 (ii) RAID Level 1+0 (iii) Swap Space (iv) C-SCAN Disk Scheduling Algo. (v) SCAN Disk Scheduling Algo. [20 marks]