Multiple choice

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 the 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?

  1. 50%

  2. 40%

  3. 25%

  4. 0%
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D Correct answer
Explanation

If the system only executes a single sequential process at a time, there is only one I/O request in the queue at any given moment. Therefore, the disk scheduling algorithm (FCFS vs SSTF) makes no difference because there is no queue to optimize.

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