[W/K] :: hard disk

  magnetic disc \magnetic disc\, magnetic disk \magnetic disk\n.
     A ditical memory device consisting of a flat disk covered
     with a magnetic coating on which information is stored; a
     hard disk, floppy disk, and diskette are typically
     magnetic disks.
  
     Syn: disk, disc.
          [WordNet 1.5]

  hard disk
       n : a rigid magnetic disk mounted permanently in a drive unit
           [syn: hard disc, fixed disk]

  hard disk
       
           (In contrast to floppy disk).  One or more rigid
          magnetic disks rotating about a central axle with associated
          read/write heads and electronics, used to store data.  Most
          hard disks are permanently connected to the drive (fixed
          disks) though there are also removable disks.
       
          High speed disks have an access time of 28 milliseconds or
          less, and low-speed disks run 65 milliseconds or more.  The
          higher speed disks also transfer their data faster than the
          slower speed units.
       
          Each surface of each disk is divided into a number of evenly
          spaced concentric circular tracks.  The set of all tracks at
          a given radius on all surfaces (the tracks which can be
          accessed without moving the heads) are known as a cylinder.
          Each track is divided into sectors.
       
          Disk drives are commonly characterised by the kind of
          interface used to connect to the computer, e.g. ATA, IDE,
          SCSI.
       
          See also winchester.
       
          http://www.pc-disk.de/).html">Suchanka's PC-DISK library (http://www.pc-disk.de/).
       
          (1999-01-07)