Operating System MCQ with Answers

Operating System MCQ with Answers

41) Disk requests are received by a disk drive for cylinders 5, 25, 18, 3, 39, 8 and 35 in that order. A seek takes 5 m sec per cylinder moved. How much seek time is needed to serve these requests for a Shortest Seek First (SSF) algorithm ? Assume that the arm is at cylinder 20 when the last of these requests is made with none of the requests yet served

Answer is:

295 msec

42) Disk requests come to a disk driver for cylinders 10, 22, 20, 2, 40, 6 and 38, in that order at a time when the disk drive is reading from cylinder 20. The seek time is 6 ms per cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is

Answer is:

876 ms

43) Disk requests come to a disk driver for cylinders 10, 22, 20, 2, 40, 6 and 38, in that order at a time when the disk drive is reading from cylinder 20. The seek time is 6 ms per cylinder.If the scheduling algorithm is the closest cylinder next, then the total seek time will be

Answer is:

360 ms

44) Disk scheduling involves deciding

Answer is:

the order in which disk access requests must be serviced

45) Poor response time are caused by

Answer is:

All of these

Explanation:

Poor response time are caused by
* Process or busy
* High I/O rate
* High paging rates

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