Suppose that a disk drive has 2000 cylinders, numbered 0 to 1999. The drive is currently serving a request at cylinder 150, and the previous request met was at cylinder 140. The queue of pending requests, in FIFO order, is

86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130

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?

FCFS

SSTF

LOOK

C-SCAN

LCFS

Longest seek time first: LSTF:

Which of the disk-scheduling disciplines mentioned above can cause starvation and which do not. Explain yoir answer. Describe a way to modify algorithms with starvation to ensure absence of starvation.