Suppose that a disk drive has 1000 cylinders, numbered 0 to 999.
- The drive is currently serving a request at cylinder 50, and the previous request was at cylinder 75.
- The queue of pending requests, in FIFO order, is 30, 45, 100, 410, 550, 700, 200, 300, 25, 150, 299, 7, 45, 33
1. 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 SSTF disk-scheduling algorithm?
2. Is the SSTF algorithm optimal? If not can you suggest a modification that will perform better than the SSTF?