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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
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Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+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:
+
+ https://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:
+
+ https://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.