Question

Consider the following five disk access requests of the form (request id, cylinder number) that are present in the disk scheduler queue at a given time
(P, 155), (Q,85), (R,110), (S, 30), (T,115)
Assume the head is positioned at cylinder 100. The sheduler follows Shortest Seek Time First scheduling to service the requests.

Which one of the following statements is FALSE?

• A. T is serviced before P.
• B. Q is serviced after S but before T.
• C. The head reverses its direction of movement between servicing of Q and P.
• D. R is serviced before P

Answer 1

The correct option is B Q is serviced after S but before T.

• Option (a) is correct as P is serviced last.
• Option (b) is correct as P is serviced last.
• Option (c) is false as Q is serviced before S.
• Option (d) is correct.