GATE - 2014 | OS | Suppose a disk has 201 cylinders, numbered from 0 to 200. At some
Posted on 10-02-2022
GATE - 2014 [Operating System]
Question:
Suppose a disk has 201 cylinders, numbered from 0 to 200. At some time the disk arm is at cylinder 100, and there is a queue of disk access requests for cylinders 30, 85, 90, 100, 105, 110, 135 and 145. If Shortest-Seek Time First (SSTF) is being used for scheduling the disk access, the request for cylinder 90 is serviced after servicing ____________ number of requests.
|
A |
3 |
|
B |
4 |
|
C |
5 |
|
D |
6 |
Solution:
Option (A) is Correct.
90 is serviced after servicing three requests, i.e.,
100 → 105 → 110 → 90