Operating Systems - Old Questions

2. When does interrupt concur? Suppose that a disk drive has the cylinder numbered from 0 to 199. The head is currently at cylinder number 53. The queue for services of cylinders is as 99, 183, 37, 122, 14, 124, 65 and 67. What is the total head movement in each of following disk algorithm to satisfy the requests?

        (a) FCFS         (b) SSTF         (c) SCAN