申論題

2. (10%) Suppose that a disk drive has 1001 cylinders, numbered from 0 to 1000. The drive is currently serving a request at cylinder 175, and the previous request was at cylinder 125. The queue of pending requests, in FIFO order, is
50,500, 225, 825, 350, 550, 400, 600, 100.
 Starting from the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests for each of the following disk scheduling algorithms?

(a) (2%) FCFS