Question

The head of a moving head disk with 100 tracks numbered from 0 to 99 is currently serving a request
at track 40. The queue of requests is 30, 70, 90, 40, 60 and is processed by the SSTF disk scheduling
algorithm. What will be the total head movement to serve these requests?​

Answer 1

The head of a moving head disk with 100 tracks numbered from 0 to 99 is currently serving a request

at track 40. The queue of requests is 30, 70, 90, 40, 60 and is processed by the SSTF disk scheduling

algorithm. What will be the total head movement to serve these requests?​

Total head movement in FCFS = 45 + 60 + 5 + 52 + 42

= 204 tracks136

Fourth Semester Operating System,

May-June 2013SSTF (Shortest Seek Time First)

0 10 23 55 65 70 75 99Initially Position

∴Total Head movement in SSTF: = 10 + 5 + 5 + 52 + 13

= 85 tracks.