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diff --git a/Documentation/admin-guide/unicode.rst b/Documentation/admin-guide/unicode.rst new file mode 100644 index 000000000000..7425a3351321 --- /dev/null +++ b/Documentation/admin-guide/unicode.rst @@ -0,0 +1,189 @@ +Unicode support +=============== + + Last update: 2005-01-17, version 1.4 + +This file is maintained by H. Peter Anvin <unicode@lanana.org> as part +of the Linux Assigned Names And Numbers Authority (LANANA) project. +The current version can be found at: + + http://www.lanana.org/docs/unicode/admin-guide/unicode.rst + +Introduction +------------ + +The Linux kernel code has been rewritten to use Unicode to map +characters to fonts. By downloading a single Unicode-to-font table, +both the eight-bit character sets and UTF-8 mode are changed to use +the font as indicated. + +This changes the semantics of the eight-bit character tables subtly. +The four character tables are now: + +=============== =============================== ================ +Map symbol Map name Escape code (G0) +=============== =============================== ================ +LAT1_MAP Latin-1 (ISO 8859-1) ESC ( B +GRAF_MAP DEC VT100 pseudographics ESC ( 0 +IBMPC_MAP IBM code page 437 ESC ( U +USER_MAP User defined ESC ( K +=============== =============================== ================ + +In particular, ESC ( U is no longer "straight to font", since the font +might be completely different than the IBM character set. This +permits for example the use of block graphics even with a Latin-1 font +loaded. + +Note that although these codes are similar to ISO 2022, neither the +codes nor their uses match ISO 2022; Linux has two 8-bit codes (G0 and +G1), whereas ISO 2022 has four 7-bit codes (G0-G3). + +In accordance with the Unicode standard/ISO 10646 the range U+F000 to +U+F8FF has been reserved for OS-wide allocation (the Unicode Standard +refers to this as a "Corporate Zone", since this is inaccurate for +Linux we call it the "Linux Zone"). U+F000 was picked as the starting +point since it lets the direct-mapping area start on a large power of +two (in case 1024- or 2048-character fonts ever become necessary). +This leaves U+E000 to U+EFFF as End User Zone. + +[v1.2]: The Unicodes range from U+F000 and up to U+F7FF have been +hard-coded to map directly to the loaded font, bypassing the +translation table. The user-defined map now defaults to U+F000 to +U+F0FF, emulating the previous behaviour. In practice, this range +might be shorter; for example, vgacon can only handle 256-character +(U+F000..U+F0FF) or 512-character (U+F000..U+F1FF) fonts. + + +Actual characters assigned in the Linux Zone +-------------------------------------------- + +In addition, the following characters not present in Unicode 1.1.4 +have been defined; these are used by the DEC VT graphics map. [v1.2] +THIS USE IS OBSOLETE AND SHOULD NO LONGER BE USED; PLEASE SEE BELOW. + +====== ====================================== +U+F800 DEC VT GRAPHICS HORIZONTAL LINE SCAN 1 +U+F801 DEC VT GRAPHICS HORIZONTAL LINE SCAN 3 +U+F803 DEC VT GRAPHICS HORIZONTAL LINE SCAN 7 +U+F804 DEC VT GRAPHICS HORIZONTAL LINE SCAN 9 +====== ====================================== + +The DEC VT220 uses a 6x10 character matrix, and these characters form +a smooth progression in the DEC VT graphics character set. I have +omitted the scan 5 line, since it is also used as a block-graphics +character, and hence has been coded as U+2500 FORMS LIGHT HORIZONTAL. + +[v1.3]: These characters have been officially added to Unicode 3.2.0; +they are added at U+23BA, U+23BB, U+23BC, U+23BD. Linux now uses the +new values. + +[v1.2]: The following characters have been added to represent common +keyboard symbols that are unlikely to ever be added to Unicode proper +since they are horribly vendor-specific. This, of course, is an +excellent example of horrible design. + +====== ====================================== +U+F810 KEYBOARD SYMBOL FLYING FLAG +U+F811 KEYBOARD SYMBOL PULLDOWN MENU +U+F812 KEYBOARD SYMBOL OPEN APPLE +U+F813 KEYBOARD SYMBOL SOLID APPLE +====== ====================================== + +Klingon language support +------------------------ + +In 1996, Linux was the first operating system in the world to add +support for the artificial language Klingon, created by Marc Okrand +for the "Star Trek" television series. This encoding was later +adopted by the ConScript Unicode Registry and proposed (but ultimately +rejected) for inclusion in Unicode Plane 1. Thus, it remains as a +Linux/CSUR private assignment in the Linux Zone. + +This encoding has been endorsed by the Klingon Language Institute. +For more information, contact them at: + + http://www.kli.org/ + +Since the characters in the beginning of the Linux CZ have been more +of the dingbats/symbols/forms type and this is a language, I have +located it at the end, on a 16-cell boundary in keeping with standard +Unicode practice. + +.. note:: + + This range is now officially managed by the ConScript Unicode + Registry. The normative reference is at: + + http://www.evertype.com/standards/csur/klingon.html + +Klingon has an alphabet of 26 characters, a positional numeric writing +system with 10 digits, and is written left-to-right, top-to-bottom. + +Several glyph forms for the Klingon alphabet have been proposed. +However, since the set of symbols appear to be consistent throughout, +with only the actual shapes being different, in keeping with standard +Unicode practice these differences are considered font variants. + +====== ======================================================= +U+F8D0 KLINGON LETTER A +U+F8D1 KLINGON LETTER B +U+F8D2 KLINGON LETTER CH +U+F8D3 KLINGON LETTER D +U+F8D4 KLINGON LETTER E +U+F8D5 KLINGON LETTER GH +U+F8D6 KLINGON LETTER H +U+F8D7 KLINGON LETTER I +U+F8D8 KLINGON LETTER J +U+F8D9 KLINGON LETTER L +U+F8DA KLINGON LETTER M +U+F8DB KLINGON LETTER N +U+F8DC KLINGON LETTER NG +U+F8DD KLINGON LETTER O +U+F8DE KLINGON LETTER P +U+F8DF KLINGON LETTER Q + - Written <q> in standard Okrand Latin transliteration +U+F8E0 KLINGON LETTER QH + - Written <Q> in standard Okrand Latin transliteration +U+F8E1 KLINGON LETTER R +U+F8E2 KLINGON LETTER S +U+F8E3 KLINGON LETTER T +U+F8E4 KLINGON LETTER TLH +U+F8E5 KLINGON LETTER U +U+F8E6 KLINGON LETTER V +U+F8E7 KLINGON LETTER W +U+F8E8 KLINGON LETTER Y +U+F8E9 KLINGON LETTER GLOTTAL STOP + +U+F8F0 KLINGON DIGIT ZERO +U+F8F1 KLINGON DIGIT ONE +U+F8F2 KLINGON DIGIT TWO +U+F8F3 KLINGON DIGIT THREE +U+F8F4 KLINGON DIGIT FOUR +U+F8F5 KLINGON DIGIT FIVE +U+F8F6 KLINGON DIGIT SIX +U+F8F7 KLINGON DIGIT SEVEN +U+F8F8 KLINGON DIGIT EIGHT +U+F8F9 KLINGON DIGIT NINE + +U+F8FD KLINGON COMMA +U+F8FE KLINGON FULL STOP +U+F8FF KLINGON SYMBOL FOR EMPIRE +====== ======================================================= + +Other Fictional and Artificial Scripts +-------------------------------------- + +Since the assignment of the Klingon Linux Unicode block, a registry of +fictional and artificial scripts has been established by John Cowan +<jcowan@reutershealth.com> and Michael Everson <everson@evertype.com>. +The ConScript Unicode Registry is accessible at: + + http://www.evertype.com/standards/csur/ + +The ranges used fall at the low end of the End User Zone and can hence +not be normatively assigned, but it is recommended that people who +wish to encode fictional scripts use these codes, in the interest of +interoperability. For Klingon, CSUR has adopted the Linux encoding. +The CSUR people are driving adding Tengwar and Cirth into Unicode +Plane 1; the addition of Klingon to Unicode Plane 1 has been rejected +and so the above encoding remains official. |