Code page: Difference between revisions

Revision as of 20:58, 16 June 2004

Revision as of 10:13, 17 June 2004

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'''Code page''' is the traditional [[International Business Machines|IBM]] term used for a specific [[character encoding]] table: a mapping in which a sequence of [[bit]]s, usually a single octet representing integer values 0 through 255, is associated with a specific character.

The basis of many code pages is [[ASCII]], originally a 7-bit code representing, at most, 128 characters. 8-bit representations of ASCII traditionallytypically either set the top bit to zero, or used it as a [[parity bit]] in network data transmissions. When this bit was instead made available for representing character data, another 128 characters could be represented. IBM used this extended range to encode characters used by various languages. No formal standard existed for these ‘[[Extended ASCII|extended character sets]]’; IBM merely referred to the variants as code pages, as it had always done for variants of [[EBCDIC]] encodings.

Although IBM created and maintained a myriad of code pages, the term came to be associated primarily with character maps used by the [[IBM PC]] and compatible platforms. Typically, one code page for a particular regional market is supported in hardware, but mechanisms were available for operating systems to enable the use of other code pages.