rotational latency


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Related to rotational latency: seek time

rotational latency

[rō′tā·shən·əl ′lāt·ən·sē]
(computer science)
The time required, following an order to read or write information in disk storage, for the location of the information to revolve beneath the appropriate read/write head.

rotational latency

The time for the start of the required sector on a disk to appear underneath the read/write head. The worst case is where it has just passed the head when the request is received. For a disk drive with N heads per surface, rotating at R revolutions per minute, the average rotational latency will be

L = 30/NR seconds.

Rotational latency is one component of access time.