Suppose that a disk drive has 2,000 cylinders numbered 0 to 1999. The drive is currently serving a request at cylinder 142, and the previous request was at cylinder 125. 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 the following disk scheduling algorithm FCFS.

Please answer immediately

Please answer it’s due tonight

7080

Explanation:

Let us suppose that seek distance = 0

Hence, We need to calculate step by step the seek distance, and then sum all together,

   142-86=56                  sd=56

    1470-86=1384                      sd= 56+ 1384=1440

    1470-913= 557             sd= 1440+557= 1997

    1774-913=861                   sd= 1997+ 861=2858

    1774-948= 826             sd=2858+826=3684

    1509-948=561             sd=3684+561=4245

    1509-1022=    487        sd=4245+487=4732

    1750-1022=728         sd=4732+728=5460

    1750-130=1620         sd=5460+1620=7080

     hence, Net sd= 7080