Dale - Computer Science Illuminated 157

Dale Computer - 130 Chapter 5 Computing Components Seek time The time it takes for the read/write head to get positioned over the specified track

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Seek time The time it takes for the read/write head to get positioned over the specified track Latency The time it takes for the specified sector to be in position under the read/write head Access time The time it takes for a block to start being read; the sum of seek time and latency. Transfer rate The rate at which data moves from the disk to memory Cylinder The set of concentric tracks on all surfaces 130 Chapter 5 Computing Components until the appropriate sector is beneath the head and the block of informa- tion in the sector is then accessed. This process gives rise to four measures of a disk drive’s efficiency: seek time , latency , access time , and transfer rate . Seek time is the time it takes for the read/write head to get positioned over the specified track. Latency is the time it takes for the specified sector to spin to the read/write head. The average latency is one-half the time for a full rotation of the disk. For this reason, latency is also called rotation delay. Access time is the sum of seek time and latency. Transfer rate is the
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This note was uploaded on 01/13/2011 for the course CSE 1550 taught by Professor Marianakant during the Fall '10 term at York University.

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