Proprietary Extensions
Various proprietary extensions appeared on non-EBCDIC mainframe computers and minicomputers, especially in universities. Atari and Commodore home computers added many graphic symbols to their non-standard ASCII (Respectively, ATASCII and PETSCII, based on the original ASCII standard of 1963).
IBM introduced eight-bit extended ASCII codes on the original IBM PC and later produced variations for different languages and cultures. IBM called such character sets code pages and assigned numbers to both those they themselves invented as well as many invented and used by other manufacturers. Accordingly, character sets are very often indicated by their IBM code page number. In ASCII-compatible code pages, the lower 128 characters maintained their standard US-ASCII values, and different pages (or sets of characters) could be made available in the upper 128 characters. DOS computers built for the North American market, for example, used code page 437, which included accented characters needed for French, German, and a few other European languages, as well as some graphical line-drawing characters. The larger character set made it possible to create documents in a combination of languages such as English and French (though French computers usually use code page 850), but not, for example, in English and Greek (which required code page 737).
Apple Computer introduced their own 8-bit extended ASCII codes in Mac OS, such as Mac OS Roman.
Digital Equipment Corporation developed the Multinational Character Set, which had fewer characters but more letter and diacritic combinations, based on draft versions of ISO 8859. It was supported by the VT220 and later DEC computer terminals.
Read more about this topic: Extended ASCII
Famous quotes containing the words proprietary and/or extensions:
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—David Lehman (b. 1948)
“If we focus exclusively on teaching our children to read, write, spell, and count in their first years of life, we turn our homes into extensions of school and turn bringing up a child into an exercise in curriculum development. We should be parents first and teachers of academic skills second.”
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