Group Code Recording
<storage >
(GCR) A recording method used for 6250 BPI magnetic tapes. GCR typically uses a group of five bits of code to represent four bits of data. The encoding ensures no more than two or three zeros occur in a row, and no more than eight or so ones occur in a row, where zeros represent an absense of magnetic change. GCR is also used on Commodore Business Machines diskette drives; the 4040, 8050, 154x, 157x and 158x series of 5.25" and 3.5" low and high density diskette drives used with 8-bit home computers circa 1977 to 1992. It was also supported on Amiga internal and external drives but only used for reading non-Amiga disks. Compare NRZI, PE.
Last updated: 2004年06月01日
Nearby terms:
Group 4 ♦ Group Code Recording ♦ group identifier ♦ Group Separator
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