24-04-2012, 04:59 PM
Operating System Question Bank
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1. Explain the layered structure of an operating system by giving typical operations and
the objects that are operated in each layer.
2. What is multiprogramming? State objective of multiprogramming. Enlist and explain
in brief various multiprogrammed operating system.
3. Define a file system. What are various components of a file system? State and explain
commonly used operations on file.
4. Draw and explain Layered File System.
5. Explain advantages and disadvantages of following file allocation methods:-
i) Contiguous Allocation
ii) Linked Allocation
iii) Indexed Allocation
6. What is disk scheduling? Explain the following types of disk scheduling by giving an
example:-
i) SSTF Scheduling
ii) C-SCAN Scheduling
7. Explain the concept of Process. Draw a process transition diagram and explain the
various process states.
8. State and explain various scheduling criteria. Explain the following scheduling
algorithms by giving an example:
i) Shortest Job First Scheduling
ii) Priority scheduling
9. Explain threads. Differentiate between heavyweight and lightweight processes.
10. What is meant by Process Control Block? Draw and explain different fields of PCB.
Explain Context Switch by giving an example.
11. State and explain various memory management techniques.
12. What are the advantages of OS portability from the point of view of
i) Component Manufacturer
ii) Independent Software vendors
iii) Programmers
iv) Users ?
13. Discuss the main difficulties in writing an OS for a real time environment.
14. Explain Distributed System.
15. Explain various methods for disk allocation.
16. What are the advantages and disadvantages of indexed allocation scheme?
17. Suppose the head of moving-head disk with 200 tracks, numbered 0 to 199 is
currently serving a request at track 143 and has just finished a request at track 125. if the
queue of requests is kept in the FIFO order
86, 147, 91, 177, 94, 150, 100, 175, 130
What is total head movement to satisfy these request for the following disk scheduling
algorithms?
i) FCFS
ii) SSTF
iii) C-SCAN
18. Which algorithm will be used for CPU scheduling in:
i) Batch OS
ii) Interactive OS
iv) Real time OS? Why?
19. State whether following are true or false with justification:
i) Multitasking is a kind of multiprogramming.
ii) Multi-user system does not imply multiprogramming.
iii) Response times are more predictable in preemptive system than in nonpreemptive
system.
20. Assume that following jobs have arrived in the order 1,2,3,4 and 5:
Job Arrival Time Burst Time Priority
1 0 15 2
2 2 3 1
3 5 5 5
4 6 8 4
5 7 12 3
Give Gantt chart and calculate Avg. Turnaround Time and Waiting Time for:
i) FCFS
ii) SRTF and Preemptive priority algorithm
21. Define the essential properties of following OS with its advantages and
disadvantages.
i) Distributed
ii) Real Time
iii) Time sharing
22. What is the purpose of Command line interpreter? Why is it usually separated from
kernel?
23. What is the purpose of system call?
24. What are the differences between user level threads and kernel level threads? Under
what circumstances one is better than other?
25. Consider the following set of process with the length of CPU burst time in
milliseconds:-
Process Burst Time Priority
P1 7 3
P2 9 2
P3 2 1
P4 1 4
P5 3 5
The processes are assumed to have arrived in the order P1, P2, P3, P4, P5 and all at time
0.
a) Draw Gantt chart, illustrating the execution of these processes using FCFS, SJF,
preemptive priority and RR (quantum = 1) scheduling.
b) What is turn around time of each process for each of the following scheduling
algorithm in Part A?
c) What is the waiting time for each process for each of the scheduling algorithms in
Part A?
d) Which of the schedule in Part A, results in the minimal average waiting
time(overall process)?
26. Explain the following:-
a) Disk Caching
b) Sector queuing