Hard disk drive

A hard disk drive (HDD), hard disk, hard drive, or fixed disk,[lower-alpha 2] is a electromechanical data storage device that uises magnetic storage tae store an retrieve digital information uisin ane or mair rigid rapidly rotatin disks (platters) coatit wi magnetic material.

Hard disk drive
Internals o 2.5-inch SATA hard disk drive
Date inventit24 December 1954; 65 years ago (1954-12-24)[lower-alpha 1]
Inventit biIBM team led bi Rey Johnson


  1. This is the oreeginal filin date o the application which led tae US Patent 3,503,060, generally acceptit as the definitive disk drive patent.[1]
  2. Further inequivalent terms uised tae describe various hard disk drives include disk drive, disk file, direct access storage device (DASD), CKD disk, an Winchester disk drive (after the IBM 3340). The term "DASD" includes other devices beside disks.


  1. Kean, David W., "IBM San Jose, A quarter century of innovation", 1977.