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238 | Chapter 8: i18n and L10n
Extended ASCII
Although ASCII defines 128 characters and a 7-bit encoding, most computers process
data in 8-bit bytes. This leaves room for 128 more characters. Of course, computer
vendors each chose their own way to deal with this situation. This led to the
development of numerous extended-ASCII character sets, each of which used a different
interpretation for the upper octets (80 through FF).
The most widely adopted extended-ASCII standard is ISO 8859. This standard
adopts the ASCII values for the first 128 characters, and provides 15 different ???parts???
that each provide a definition for the last 128 characters. In effect, ISO 8859 defines
15 separate character sets.
The most used of these character sets is ISO-8859-1 (Latin-1). This provides nearly
complete coverage for most Western European languages. In fact, the 256 characters
defined by ISO-8859-1 correspond to the first 256 code points of Unicode. ISO-
8859-1 is still in widespread use among languages that use the Latin alphabet.
Problems with ASCII
Though the extended ASCII character encodings were widely successful for years,
they only provided a temporary fix. With so many encodings floating around, it is
difficult for people to communicate.
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