END TERM EXAMINATION
FIFTH SEMESTER [BCA 2014]
Operating SystemPaper Code : BCA- 301
Time : 3 Hours Maximum Marks:75
Note: Attempt any five questions. Question 1 is compulsory. Select one question from each section.
(5 x 5 = 25 marks)(a) Explain multi programming and multi tasking systems.
(b) Explain logical versus physical address space.
(c) List the differences between preemptive and non-preemptive scheduling.
(d) Explain bit-interleaved parity organization and block-interleaved parity organization.
(e) Explain logical and physical file system.
(a) Discuss various types of fragmentation and memory allocation strategies. (7.5)
(b) Explain the concept of thrashing. (5)
(a) What is page replacement? What is its importance? Explain Least Recently Used (LRU) Replacement algorithm. (7.5)
(b) The following reference string (access sequence) is given:
0, 7, 1, 4, 3, 8, 1, 4, 3, 9, 1, 4,3, 2, 7, 5, 6Find the number of page faults for a main memory susbsystem that has 4 frames and
uses LRU page replacement policy for on demanding paging. (5)
|Process||Arrival Time||Burst Time|
(b) Discuss Round robin scheduling algorithm and Priority Scheduling algorithm. (7.5)
(a) What is semaphore? Describe the Readers-Writers problems. (7.5)
(b) What is the critical section problem? What are the three requirements that must be satisfied by a good solution to the critical section problem? (5)
(a) Discuss Banker's algorithm in detail. (7.5)
(b) Discuss Resource Allocation Graph Algorithm in detail. (5)
(a) Discuss various types of disk scheduling techniques. (7.5)
(b) Explain the concept of buffering. (5)
(a) Explain directory structure of file system. (7.5)
(b) Discuss general model of file system. (5)
(a) What are the different approaches to user authentication? (5)
(b) Explain the various types of threats to systems security. (7.5)