CJKV Information Processing, 2nd Edition

Legacy Encoding Methods

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Legacy Encoding Methods

e following sections describe legacy encoding methods, which include locale-

independent and locale-specic encoding methods. ese encoding methods are impor-

tant, and will continue to be important. Many documents are stored according to these

encoding methods, and many systems that use these encoding methods still persist. Al-

though their use is diminishing, it will take years or decades for them to go away com-

pletely. For this reason, environments that support Unicode must still interoperate with

these legacy encoding methods.

Locale-Independent Legacy Encoding Methods

is is probably one of the most important sections of this book, and it lays the founda-

tion for your complete understanding of the various CJKV encoding methods, beyond

the encodings for Unicode, so be sure to take some extra time to read and study this

material well. Some of the legacy encoding methods described here, specically ISO-2022

and EUC, will serve as a basis for drawing comparisons between other encodings and for

discussions that appear later in this book.

ASCII and CJKV-Roman encodings

ASCII and CJKV-Roman (GB-Roman, CNS-Roman, JIS-Roman, KS-Roman, and

TCVN-Roman) are considered dierent character set standards, but they share the same

encoding.

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e denition of the encoding method for the ASCII character set is found

in the ...