Question

Given the following list of cylinder requests in order in which they were received, assume that the disk is positioned at cylinder 25 and list the order in which these requests would be handled using each of the following disk scheduling algorithms:

request list: 22, 3, 85, 14, 57, 36, 92, 46, 18, 71

a. first-come, first-served
b. shortest-seek-time-first
c. scan if the cylinder is moving toward the higher cylinder numbers

Answer 1

The correct answer is option b. shortest-seek-time-first. The order of handling disk requests varies according to the disk scheduling algorithm used: first-come.

Step-by-step explanation:

For the given list of requests (22, 3, 85, 14, 57, 36, 92, 46, 18, 71) and the disk initially at cylinder 25, here's how the requests would be handled:

1. First-come, first-served: 22, 3, 85, 14, 57, 36, 92, 46, 18, 71
2. Shortest-seek-time-first: 22, 18, 14, 3, 36, 46, 57, 71, 85, 92
3. Scan (towards higher cylinders): 36, 46, 57, 71, 85, 92, 22, 18, 14, 3

This example assumes the Scan algorithm is initially moving in the direction of increasing cylinder numbers.

The correct answer is option b. shortest-seek-time-first. Below is the order in which the requests would be handled using each disk scheduling algorithm:

a. first-come, first-served: 22, 3, 85, 14, 57, 36, 92, 46, 18, 71

b. shortest-seek-time-first: 22, 14, 18, 3, 36, 46, 57, 85, 71, 92

c. scan if the cylinder is moving toward higher cylinder numbers: 3, 14, 18, 22, 36, 46, 57, 71, 85, 92