Operating Systems - Jun 2014
Computer Science Engg. (Semester 5)
TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Explain multiprogramming and time sharing operating systems.(8 marks) 1 (b) List out the different serviies that an OS provides? Explain any two.(6 marks) 1 (c) What are the different categories of system program? Explain.(6 marks) 2 (a) With neat dragram, explain components of PCB.(5 marks) 2 (b) Explain direct and indirect communication with respect to message passing systems.(5 marks) 2 (c) Consider following set of processes with CPU burst time (in msec)
i) Draw Gantt chart illustrating the execution of above processes using SRTF and non preemptive SJF
ii) Find the turn around time for each processes for SRTF and SJF. Hence show that SRTF is faster than SJF. (10 marks) 3 (a) What do you mean by a binary semaphore and counting semaphore? Explain the of implementation of Wait( ) and signal() semaphore operations.(10 marks) 3 (b) What is race condiiton? List the requirements that a solution to critical section must satisfy.(5 marks) 3 (c) Explain any one synchronization problem for testing newly proposed synchronization scheme.(5 marks) 4 (a) Consider the following snapshot of resource allocation at time t1.
(i) Show that the system is not deadlock by generating one safe sequence
(ii) At instance t, P2 makes one additional for instance of type C. show that the system is deadlocked if the request is granted. write down the deadlocked processes.(8 marks) 4 (b) Describe resource allocaltion graph
(i) With deadlock (ii) With a cycle no deadlock.(6 marks) 4 (c) What is wait for graph? Explain it is useful for detection of deadlock.(6 marks) 5 (a) Explain the internal and exteranal fragmentation with examples.(6 marks) 5 (b) Consider the following page reference string 1,2,3,4,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6 how many page fault would occur for the following page replacement algorithms assuming 3 and 5 frames, (i) LRU (ii) optimal (10 marks) 5 (c) What is the cause of Thrashing? How does the system detect thrashing?(4 marks) 6 (a) What do you mean by free space list? What suitable example, explin any two methods of implementation of free space list.(8 marks) 6 (b) What are the three methods for allocation disk space? Explain with suitable example.(12 marks) 7 (a) Suppose that a disk has 50 cylinder named 0 to 49. The R/W head is currently serving at cylinder 15. The queue of pending request are in order: 4 40 11 35 7 14 starting from the current head position, what is the total distance traveled (in cylinders) by the disk arm to satisfy the request using algorithms FCFS, SSTF and LOOK. Illustrate with fidure in each case.(12 marks) 7 (b) Write a note on:
(i) Domain of protection
(ii) Access matrix.(8 marks) 8 (a) With diagram, explain components of Linux system.(8 marks) 8 (b) Explain in detail, the components that the keranal module support under Linux.(12 marks)