Access time has two major components seek time time

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Unformatted text preview: ek time : time for the drive to move the heads to the cylinder containing the desired sector. (slowest part) Rotational latency is the additional time waiting for the disk to rotate the desired sector to the disk head. Disk I/O Scheduling Multiple applications running concurrently may issue multiple disk I/O requests Note: read requests are generally more critical than write requests physical locations may be scattered all over the disk request may be read or write request may be blocking or nonblocking When the I/O system dispatches an I/O request, the I/ O Scheduler selects a request to send to the dispatch queue Block Layer (producer) I/O Scheduler Dispatch Queue Device Driver (consumer) Disk I/O Scheduling I/O Scheduling Algorithm should ... Minimize access time Maximize bandwidth Seek time + rotational latency...
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This note was uploaded on 06/28/2009 for the course CS 411 taught by Professor Staff during the Spring '08 term at Oregon State.

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