GTU Computer Engineering (Semester 4)
Operating System
June 2014
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1 (a) Explain the objectives and functions of operating systems.
7 M
1 (b) Define a process. Explain the process state transition with a neat diagram.
7 M

2 (a) What is thread and what are the differences between user-level threads and kernel supported threads? Under what circumstances is one type 'better' than the other?
7 M
2 (b) Explain the Problem of Critical Section (CSP) through Producer Consumer Problem. Explain any one Solution in detail.
7 M
2 (c) Write short note: 1) Semaphores 2) Monitors
7 M

3 (a) Find average waiting time for Shortest job first scheduling, and Round robin scheduling algorithm.
Process CPU burst time
P1 6
P2 8
P3 5
P4 2

CPU burst time is given in millisecond and time quantum is 4.
7 M
3 (b) What do you mean by Deadlock Avoidance? Explain the use of Banker's Algorithm for Deadlock Avoidance with illustration.
7 M
3 (c) Consider the following set of processes with the length of CPU burst time given in the milliseconds.
Process Arrival Time Burst Time Priority
P1 0 8 3
P2 1 1 1
P3 2 3 2
P4 3 2 3
P5 4 6 4

Calculate average turnaround time and average waiting time for First-come first served scheduling, Shortest job first scheduling and Priority scheduling algorithm.
7 M
3 (d) What is Deadlock? List the conditions that lead to deadlock. How Deadlock can be prevented?
7 M

4 (a) Explain the following allocation algorithms: 1) First-fit 2) Best-fit 3) Worst-fit
7 M
4 (b) Write short note: 1) Direct memory access (DMA) 2) Device controllers
7 M
4 (c) What is fragmentation? What is the need of fragmentation? Explain the difference between internal and external fragmentation.
7 M
4 (d) Write short note: RAID levels
7 M

5 (a) Explain in details about file attributes and file operations.
7 M
5 (b) What is 'inode'? Explain File and Directory Management of Unix Operating System.
7 M
5 (c) Describe various file organization Techniques.
7 M
5 (d) Define distributed system. Explain the characteristics of distributed system.
7 M

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