# Compare the algorithms and explain which algorithm is the most efficient (the shortest distance) for this scenario.

To complete this assignment, consider the following scenario:

A disk drive has 300 cylinders, numbered 0 to 299. The drive is currently serving a request at cylinder 51, and the previous request was at cylinder 56. The pending requests are received in the following order: 72, 56, 103, 111, 17, 189, 236, 198, and 88.

Describe how the disk arm moves to satisfy all the pending requests for each of the following disk-scheduling algorithms. (Perhaps you create a diagram similar to the diagrams in Section 9.4 to support your explanation.)

FCFS

SSTF

SCAN

Calculate the total distance (in cylinders) that the disk arm moves for each of the above disk-scheduling algorithms. Compare the algorithms and explain which algorithm is the most efficient (the shortest distance) for this scenario. Write a minimum of 250 words.

Part 2:

Compare the algorithms and determine which is the fairest for the next process in the queue. Explain why this algorithm will always be the fairest disk-scheduling algorithm.

Describe an example of circumstances where fairness would be an important goal. Describe a scenario where it would be important that the operating system be unfair.