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]
Operating Systems: Three Easy Pieces by Remzi H. Arpaci-Dusseau and others. Chapter 37, Hard Disk Drives, §37.3, seek, rotation and transfer phases
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