ROTATIONAL LATENCY

1/11/97

Rotational Latency: Many mass storage devices -- disks, CDROMs, drums -- store data on rotating media. When these devices are accessed, there is a delay while the device rotates the desired area under the read/write mechanism. If the accessing is random, the average delay -- the rotational latency -- is one half the rotation speed. Various techniques, read-ahead, caching, skewing, etc are used to overcome rotational latency for non-random accessing. Rotational Latency can be decreased by faster rotation or by the use of multiple read write heads.

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