Answer Happy

Suppose that a disk drive has 10,000 cylinders, numbered 0 to
9999. The drive is currently serving a request at cylinder 1400 and
is moving towards cylinder 9999. The queue of pending request is,
in the order received: 100, 1200, 900, 8000, 8100, 100, 8200, 1000,
4200.
(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 FCFS? Show your steps.
(2) 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? Show your steps.
(3) 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 SCAN? Show your steps.
(4) 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 C-LOOK? (Assume that we ignore the leap
distance when calculating the C-LOOK distance.)