Code page: Difference between revisions

Revision as of 11:06, 16 June 2004

Revision as of 20:48, 16 June 2004

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[[fr:Page de code]]

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

Although theThe basis of many charactercode setspages is [[ASCII]], ASCII wasoriginally a seven 7-bit code representing, withat themost, 128 characters. 8-bit representationrepresentations of ASCII typicallytraditionally either settingset the top bit to zero, or usingused it as a [[parity bit]] in network data transmissions. UsingWhen this bit forwas datainstead doubledmade theavailable sizefor of the possiblerepresenting character setdata, allowing another 128 characters tocould be addedrepresented. IBM used this extended range to encode characters used by various languages. No formal standard existed for these ‘[[Extended ASCII|extended character sets]]’, and; 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 hascame into widerbe useassociated takenprimarily onwith thecharacter meaning charactermaps codingused forby the [[IBM PC]]. Since the original IBM PC code page was not really designed for international use, several incompatible variants emerged:

* 437 -- Original PC extended character set

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* 1252 -- Superset of [[ISO 8859-1]], used by [[Microsoft Windows]]

The IBM PC code pages have now been rendered obsolete by international standards, specificallysuch as [[ISO 8859-1]] and [[Unicode]].

Other code pages of note are:

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* not interoperating with documents produced with Microsoft applications

* mis-rendering the text in question

* adding full support for the Microsoft code pages, in effect making Microsoft's implementation a ''de facto'' standard.

These code pages are often viewed as part of Microsoft’s [[embrace, extend and extinguish]] strategy towards open standards. Fortunately, the transition to full [[Unicode]] support now offers standards-based applications the possibility of full interoperability with the [[character repertoire]] of these documents without giving up standards compliance on output.