Consider an operating system capable of loading and executing a single…
20042022
Consider an operating system capable of loading and executing a single sequential user process at a time. The disk head scheduling algorithm used is First Come First Served (FCFS). If FCFS is replaced by Shortest Seek Time First (SSTF), claimed by the vendor to give 50% better benchmark results, what is the expected improvement in the I/O performance of user programs?
- A.
50%
- B.
40%
- C.
25%
- D.
0%
Attempted by 81 students.
Show answer & explanation
Correct answer: D
Disk scheduling algorithms like SSTF optimize seek time by reordering I/O requests from a queue of multiple processes. In this scenario, the OS executes only one sequential user process at a time. Consequently, there is no queue of competing requests to reorder; the I/O requests follow a fixed sequential order regardless of the algorithm. Since FCFS and SSTF will process the same sequence, switching algorithms yields no reduction in seek time. The expected improvement is 0%.
A video solution is available for this question — log in and enroll to watch it.