1. Disk requests come in to the disk driver for cylinders 10, 22, 20, 12, 40, 6, and 38, in that order. A seek takes 5 msec per cylinder. Calculate

1. how many cylinders disk arm motion and
2. how much seek time is needed for-

(a) First-come, first served.

(b) Closest cylinder next.

(c) Elevator algorithm (initially moving upward).

In all cases, the arm is initially at cylinder 12.