hard disc

Definition: Device for storing large quantities of digital data: consists of a series of thin, rigid, circular discs coated with magnetic material on which data is stored as series of minute fields with differing polarities. * The discs spin at 5400 - 7200 or more rpm under a head which lies extremely close to the disc -- only a few millionths of an inch away -- to read off the changing magnetic fields. A hard disc may consist of a stack of one to eight or more discs on a shared central spindle. * Modern hard dics carry from 20GB to 100GB or more per unit. * Some types, now obsolete, e.g. Zip, Jaz discs used removable discs enclosed in a casing.

Previous Term: hard  Next Term: hardcopy