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A data storage device that records information magnetically on rotating platters. Accessing a sector can require moving a head to its track, waiting for the sector to rotate beneath it, and transferring the data. These contributions are seek time, rotational latency and data transfer time.^[ref]

At 6000 revolutions per minute the disk makes 100 revolutions per second, so one turn takes 10 ms and the mean rotational latency is 5 ms. Adding seek time, data transfer time and controller overhead gives, using decimal MB,Using $1\mathrm{MB}=2^{20}$ bytes instead gives 19.09765625 ms, with the same rounded answer. The calculation assumes the stated rate applies to the sector transfer and that the seek and overhead are each paid once.