9. Explain the SCAN disk scheduling algorithm. Explain why it is sometimes called the Elevator Algorithm.

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9. Explain the SCAN disk scheduling algorithm. Explain why it is sometimes called the Elevator Algorithm.

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Answer 1

Answer #1

SCAN Disk Scheduling Algorithm:-

The disk arm moves into a specific direction till the end, processing all the requests coming in its path,and if it reaches the end in one direction then it turns back and moves in the reverse direction processing the requests coming in its path.

Example:-

Consider the following disk request sequence for a disk with 100 tracks 98, 137, 122, 183, 14, 133, 65, 78 Head pointer start

2 Example:-

ccnsider a disk 9ueue uitt request fr. т/oblochten Cyinders 99, ry, 131, 13,1, 46,The SCAN 53 mou head movements ωhile Servic

Advantages:-

It is easy to understand and implement.

It does not lead into starvation.

Disadvantages:-

It causes the head to move upto the end of the disk even if there are no requests to be processed.

WHY SCAN ALGORITHM IS CALLED ELEVATOR ALGORITHM:-

It is similar to the work of the elevator like the elavator moves in any one of the direction and process the people in that way.

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Answer 2

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9. Explain the SCAN disk scheduling algorithm. Explain why it is sometimes called the Elevator Algorithm.

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9. Explain the SCAN disk scheduling algorithm. Explain why it is sometimes called the Elevator Algorithm.

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