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Unicode. (Wikipedia Part 3.)

created Sep 25th 2014, 00:39 by Nehemiah Thomas


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The Unicode Consortium is a nonprofit organization that coordinates Unicode's development. Full members include most of the main computer software and hardware companies with any interest in text-processing standards, including Adobe Systems, Apple, Google, IBM, Microsoft, Oracle Corporation, Yahoo! and the Ministry of Endowments and Religious Affairs of Sultanate of Oman.[17]
The Consortium has the ambitious goal of eventually replacing existing character encoding schemes with Unicode and its standard Unicode Transformation Format (UTF) schemes, as many of the existing schemes are limited in size and scope and are incompatible with multilingual environments. Unicode is developed in conjunction with the International Organization for Standardization and shares the character repertoire with ISO/IEC 10646: the Universal Character Set. Unicode and ISO/IEC 10646 function equivalently as character encodings, but The Unicode Standard contains much more information for implementers, covering—in depth—topics such as bitwise encoding, collation and rendering. The Unicode Standard enumerates a multitude of character properties, including those needed for supporting bidirectional text. The two standards do use slightly different terminology.
The Consortium first published The Unicode Standard (ISBN 0-321-18578-1) in 1991 and continues to develop standards based on that original work. The latest version of the standard, Unicode 7.0, was released in June 2014 and is available from the consortium's web site. The last of the major versions (versions x.0) to be published in book form was Unicode 5.0 (ISBN 0-321-48091-0), but since Unicode 6.0 the full text of the standard is no longer being published in book form. In 2012, however, it was announced that only the core specification for Unicode version 6.1 would be made available as a 692 page print-on-demand paperback.[18] Unlike the previous major version printings of the Standard, the print-on-demand core specification does not include any code charts or standard annexes, but the entire standard, including the core specification, will still remain freely available on the Unicode website.
Thus far the following major and minor versions of the Unicode standard have been published. Update versions, which do not include any changes to character repertoire, are signified by the third number (e.g. "version 4.0.1") and are omitted in the table below.[19] 1.0.0    October 1991    ISBN 0-201-56788-1 (Vol.1)        24    7,161    Initial repertoire covers these scripts: Arabic, Armenian, Bengali, Bopomofo, Cyrillic, Devanagari, Georgian, Greek and Coptic, Gujarati, Gurmukhi, Hangul, Hebrew, Hiragana, Kannada, Katakana, Lao, Latin, Malayalam, Oriya, Tamil, Telugu, Thai, and Tibetan.[20]
1.0.1    June 1992    ISBN 0-201-60845-6 (Vol.2)        25    28,359    The initial set of 20,902 CJK Unified Ideographs is defined.[21]
1.1    June 1993        ISO/IEC 10646-1:1993    24    34,233    4,306 more Hangul syllables added to original set of 2,350 characters. Tibetan removed.[22]
2.0    July 1996    ISBN 0-201-48345-9    ISO/IEC 10646-1:1993 plus Amendments 5, 6 and 7    25    38,950    Original set of Hangul syllables removed, and a new set of 11,172 Hangul syllables added at a new location. Tibetan added back in a new location and with a different character repertoire. Surrogate character mechanism defined, and Plane 15 and Plane 16 Private Use Areas allocated.[23]
2.1    May 1998        ISO/IEC 10646-1:1993 plus Amendments 5, 6 and 7, as well as two characters from Amendment 18    25    38,952    Euro sign added.[24]
3.0    September 1999    ISBN 0-201-61633-5    ISO/IEC 10646-1:2000    38    49,259    Cherokee, Ethiopic, Khmer, Mongolian, Burmese, Ogham, Runic, Sinhala, Syriac, Thaana, Unified Canadian Aboriginal Syllabics, and Yi Syllables added, as well as a set of Braille patterns.[25]
3.1    March 2001        ISO/IEC 10646-1:2000
ISO/IEC 10646-2:2001
41    94,205    Deseret, Gothic and Old Italic added, as well as sets of symbols for Western music and Byzantine music, and 42,711 additional CJK Unified Ideographs.[26]
3.2    March 2002        ISO/IEC 10646-1:2000 plus Amendment 1
ISO/IEC 10646-2:2001
45    95,221    Philippine scripts Buhid, Hanunó'o, Tagalog, and Tagbanwa added.[27]
4.0    April 2003    ISBN 0-321-18578-1    ISO/IEC 10646:2003    52    96,447    Cypriot syllabary, Limbu, Linear B, Osmanya, Shavian, Tai Le, and Ugaritic added, as well as Hexagram symbols.[28]
4.1    March 2005        ISO/IEC 10646:2003 plus Amendment 1    59    97,720    Buginese, Glagolitic, Kharoshthi, New Tai Lue, Old Persian, Syloti Nagri, and Tifinagh added, and Coptic was disunified from Greek. Ancient Greek numbers and musical symbols were also added.[29]
5.0    July 2006    ISBN 0-321-48091-0    ISO/IEC 10646:2003 plus Amendments 1 and 2, as well as four characters from Amendment 3    64    99,089    Balinese, Cuneiform, N'Ko, Phags-pa, and Phoenician added.[30]
5.1    April 2008        ISO/IEC 10646:2003 plus Amendments 1, 2, 3 and 4    75    100,713    Carian, Cham, Kayah Li, Lepcha, Lycian, Lydian, Ol Chiki, Rejang, Saurashtra, Sundanese, and Vai added, as well as sets of symbols for the Phaistos Disc, Mahjong tiles, and Domino tiles. There were also important additions for Burmese, additions of letters and Scribal abbreviations used in medieval manuscripts, and the addition of capital ß.[31]
5.2    October 2009        ISO/IEC 10646:2003 plus Amendments 1, 2, 3, 4, 5 and 6    90    107,361    Avestan, Bamum, Egyptian hieroglyphs (the Gardiner Set, comprising 1,071 characters), Imperial Aramaic, Inscriptional Pahlavi, Inscriptional Parthian, Javanese, Kaithi, Lisu, Meetei Mayek, Old South Arabian, Old Turkic, Samaritan, Tai Tham and Tai Viet added. 4,149 additional CJK Unified Ideographs (CJK-C), as well as extended Jamo for Old Hangul, and characters for Vedic Sanskrit.[32]
6.0    October 2010        ISO/IEC 10646:2010 plus the Indian rupee sign    93    109,449    Batak, Brahmi, Mandaic, playing card symbols, transport and map symbols, alchemical symbols, emoticons and emoji. 222 additional CJK Unified Ideographs (CJK-D) added.[33]
6.1    January 2012        ISO/IEC 10646:2012    100    110,181    Chakma, Meroitic cursive, Meroitic hieroglyphs, Miao, Sharada, Sora Sompeng, and Takri.[34]
6.2    September 2012        ISO/IEC 10646:2012 plus the Turkish lira sign    100    110,182    Turkish lira sign.[35]
6.3    September 2013        ISO/IEC 10646:2012 plus six characters    100    110,187    5 bidirectional formatting characters.[36]
7.0    June 2014        ISO/IEC 10646:2012 plus Amendments 1 and 2, as well as the Ruble sign    123    113,021    Bassa Vah, Caucasian Albanian, Duployan, Elbasan, Grantha, Khojki, Khudawadi, Linear A, Mahajani, Manichaean, Mende Kikakui, Modi, Mro, Nabataean, Old North Arabian, Old Permic, Pahawh Hmong, Palmyrene, Pau Cin Hau, Psalter Pahlavi, Siddham, Tirhuta, Warang Citi, and Dingbats.[37] Unicode covers almost all scripts (writing systems) in current use today.[39][not in citation given]
A total of 123 scripts are included in the latest version of Unicode (covering alphabets, abugidas and syllabaries), although there are still scripts that are not yet encoded, particularly those mainly used in historical, liturgical, and academic contexts. Further additions of characters to the already encoded scripts, as well as symbols, in particular for mathematics and music (in the form of notes and rhythmic symbols), also occur.
The Unicode Roadmap Committee (Michael Everson, Rick McGowan, and Ken Whistler) maintain the list of scripts that are candidates or potential candidates for encoding and their tentative code block assignments on the Unicode Roadmap page of the Unicode Consortium Web site. For some scripts on the Roadmap, such as Jurchen, Shu, and Tangut, encoding proposals have been made and they are working their way through the approval process. For others scripts, such as Mayan and Rongorongo, no proposal has yet been made, and they await agreement on character repertoire and other details from the user communities involved.
Some modern invented scripts which have not yet been included in Unicode (e.g., Tengwar) or which do not qualify for inclusion in Unicode due to lack of real-world use (e.g., Klingon) are listed in the ConScript Unicode Registry, along with unofficial but widely used Private Use Area code assignments.
There is also a Medieval Unicode Font Initiative focused on special Latin medieval characters. Part of these proposals have been already included into Unicode.
The Script Encoding Initiative, a project run by Deborah Anderson at the University of California, Berkeley was founded in 2002 with the goal of funding proposals for scripts not yet encoded in the standard. The project has become a major source of proposed additions to the standard in recent years.[40] Several mechanisms have been specified for implementing Unicode. The choice depends on available storage space, source code compatibility, and interoperability with other systems.  Unicode defines two mapping methods: the Unicode Transformation Format (UTF) encodings, and the Universal Character Set (UCS) encodings. An encoding maps (possibly a subset of) the range of Unicode code points to sequences of values in some fixed-size range, termed code values. The numbers in the names of the encodings indicate the number of bits in one code value (for UTF encodings) or the number of bytes per code value (for UCS) encodings. UTF-8 and UTF-16 are probably the most commonly used encodings. UCS-2 is an obsolete subset of UTF-16; UCS-4 and UTF-32 are functionally equivalent.
 

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