7. Disk requests are received by a disk drive for cylinders 5, 25, 18, 3, 39, 8 and 35 in that order. 4 seek takes 5 msec per cylinder moved. How much seek time is needed to serve these requests for a...

Extracted text: 7. Disk requests are received by a disk drive for cylinders 5, 25, 18, 3, 39, 8 and 35 in that order. 4 seek takes 5 msec per cylinder moved. How much seek time is needed to serve these requests for a shortest seek first (SSF) algorithm? Assume that the arm is at cylinder 20 when the last of these requests is made with name of the requests yet served.