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GB 18030

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Template:Table Unicode GB18030 is the registered Internet name for the official character set of the People's Republic of China (PRC). This character set is formally called "Chinese National Standard GB 18030-2000: Information Technology -- Chinese ideograms coded character set for information interchange -- Extension for the basic set". GB abbreviates Guojia Biaozhun (国家标准), which means national standard in Chinese. The standard was published by the China Standard Press, Beijing, March 17, 2000 and updated November 20, 2000. As of September 1, 2001, support for this character set is officially mandatory for all software products sold in the PRC.

GB18030 can be considered as a Unicode Transformation Format, i.e. an encoding of all Unicode code points that maintains compatibility with a legacy character set. In other words, as a Chinese equivalent of UTF-8, which maintains compatibility with ASCII. Like UTF-8, GB18030 is a superset of ASCII and can represent the whole range of Unicode code points. GB18030 also maintains compatibility with GBK, which was the pre-existing standard character encoding used in the PRC, with the aim of simplifying the upgrade of data and software to use GB18030. Part of the mapping data is from a lookup table (similarly to GBK). The rest is calculated algorithmically.

Most major computer companies had already standardised on some version of Unicode as the primary format for use in their binary formats and OS calls. However, they mostly had only supported code points in the BMP originally defined in Unicode 1.0, which supported only 65,536 codepoints and was often encoded in 16 bits as UCS-2.

In a move of historic significance, the PRC decided to mandate support of certain code points outside the BMP. This means that software can no longer get away with treating characters as 16 bit fixed width entities (UCS-2). Therefore they must either process the data in a variable width format (such as UTF-8 or UTF-16), which are the most common choices, or move to a larger fixed width format (such as UCS-4 or UTF-32). Microsoft made the change from UCS-2 to UTF-16 with Windows 2000.

The SimSun 18030 font enables the display of the GB 18030 characters, which includes all the characters in Unicode 2.1 plus new characters found in the Unicode CJK Unified Ideographs Extension A section.

See also

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