Operating Systems - May 2014

Information Technology (Semester 5)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Define and explain the following terms :
(i) Process
(ii) Process state
(iii) Multiprogramming
(iv) Time-sharing(5 marks) 1 (b) Draw and explain process state diagram. Can process make a transition from a ready state to the blocked state? Why or why not?(5 marks) 1 (c) What is a system call? Explain any four system calls.(5 marks) 1 (d) Explain effect of page size on performance.(5 marks) 2 (a) Define the notion of deadlock. Explain necessary and sufficient conditions for a deadlock to occur. What is the different between a deadlocked state and an unsafe state?(10 marks) 2 (b) Describe the difference between pre-emptive and non-pre-emptive scheduling algorithms. Which one is more suitable for a time-sharing system? Justify.(10 marks) 3 (a) What are the different file allocation methods? Which file allocation method would you see for a system whose main task is database management? Why (10 marks) 3 (b) Briefly explain the different modes of inter-process communication.(10 marks) 4 (a) Briefly explain how message passing canbe used to achived mutual exclusion. Compare this techniques with semaphore and monitors.(10 marks) 4 (b) What is the critical section problem? Discuss a solution to the problem(10 marks) 5 (a) There are five process A to E which are waiting to be scheduled. Their arrival times are 0,1,3,9 and 12 sec respectively and their processing times are 3,5,2,5 and 5 seconds respectively. What is the average turn-around time using FCFS, SJF and Round -RObin(with a quantum of 1 sec) scheduling?(10 marks) 5 (b) What are the requirements of memory management? Explain segmentation with the help of an example.(10 marks) 6 (a) What are process and threads? What are the advantages and disadvantages of implementing threads in kernal space and user space?(10 marks) 6 (b) Compare and contrast any three disk arm scheduling algorithms.(10 marks)

Short notes on :

7 (a) Unix File Management(5 marks) 7 (b) I/O buffering (5 marks) 7 (c) Real Time Operating System(5 marks) 7 (d) RAID(5 marks)