Also called
rotational delay, the amount of time it takes for the desired
sector of a
disk (i.e., the sector from which data is to be
read or
written) to rotate under the read-write
heads of the
disk drive. The average rotational latency for a disk is half the amount of time it takes for the disk to make one revolution. The term typically is applied to rotating storage devices, such as
hard disk drives and
floppy drives (and even older
magnetic drum systems), but not to tape drives.
