Operating Systems – Question Bank

1. Write short notes on: starvation, preemptive process scheduling.
2. Explain the concept of virtual memory using simple paging technique.
3. Describe the activities of the process management module of an operating system.
4. Write a note on  services provided by an OS.
5. Define multiprogramming. Explain how multiprogramming increases CPU utilization.
6. Explain how mutual exclusion is implemented using a semaphore.
7. What are the benefits of multiprogramming? Bring out any two differences between a thread and a process.
8. Write a note on functions of a scheduler.
9. Explain thrashing, its causes and effects.
10. Describe Scan and C_Scan disk scheduling techniques.
11. Explain the direct memory access method of performing I/O.
12. Explain demand paging .
13. Write a short note on Unix architecture.
14. Explain awk editor with any three keywords used to edit a file.
15. What are shell metacharacters? Explain with an example.
16. Explain grep command with any four options.
17. What is paging? Explain the basic method used for paging.
18. Define the terms worm, virus and DOS.
19. What is monitor? Explain its usage.
20. Define a thread. Explain the three common ways of establishing the relation between user level and kernel level thread.
21. Describe the conditions for which deadlock situation occurs.
22. Explain the various operations that can be performed on a directory.
23. Explain any four OS services.
24. Explain the need for context switching.
25. Discuss Peterson’s algorithm.
26. Write a short note on types of system calls.
27. Write short note on safe and unsafe states.
28. Explain round-robin scheduling algorithm. Use an appropriate example.
29. Describe the producer-consumer (Bounded buffer) problem and write the semaphore based algorithm for the same. Explain the steps of the algorithm and assumptions made in the algorithm.
30. For the following page reference string  9,0,1,0 8,1,8,7,8,7, 1,2,8,2, 7,8,2,3,8,3  determine the number of page faults for the given page replacements algorithms with 3 frames :
(i) OPT (optimal)
(ii) FIFO
(iii) LRU

31. Consider the following set of processes, with the length of the CPU burst time given in milliseconds :
Process     Burst Time
P1                9
P2              10
P3              12
P4                8
P5              13

All five processes arrive at time O, in the order given. Draw Gantt charts illustrating the execution of the processes using FCFS, SIF and RR (quantum=l) scheduling. What is the turnaround time of each process for each of the scheduling algorithms ? Also find the average waiting time for each algorithm.