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KOI-7

KOI-7 (КОИ-7) is a 7-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet.

In Russian, KOI-7 stands for Kod Obmena Informatsiey, 7 bit (Код Обмена Информацией, 7 бит) which means "Code for Information Exchange, 7 bit".[1]

It was first standardized in GOST 13052-67 (with the 2nd revision GOST 13052-74 / ST SEV 356-76) and GOST 27463-87 / ST SEV 356-86.

Shift Out (SO) and Shift In (SI) control characters are used in KOI-7, where SO starts printing Russian letters (KOI-7 N1), and SI starts printing Latin letters again (KOI-7 N0), or for lowercase and uppercase switching. This version is also known as KOI7-switched aka csKOI7switched.[2][3]

On ISO 2022 compatible computer terminals KOI7-switched can be activated by the escape sequence ESC ( @ ESC ) N LS0.[2]

KOI-7 was used on machines like the SM EVM (СМ ЭВМ) and DVK (ДВК); KOI-7 N2 was utilized in the machine-language of the Электроника Д3-28 [ru] (Elektronika D3-28) as four-digit hexadecimal code, БЭСМ-6 [ru] (BESM-6), where it was called ВКД, (internal data code). The encodings were also used on RSX-11, RT-11 and similar systems.[4]

KOI-7 N0

KOI-7 N0[2] (КОИ-7 Н0[1]) is identical to the IRV set in ISO 646:1967.[2] Compared to US-ASCII, the dollar sign ("$") at code point 24 (hex) was replaced by the universal currency sign "¤", but this was not maintained in all cases, in particular not after the fall of the Iron Curtain. Likewise, the IRV set in ISO/IEC 646:1991 also changed the character back to a dollar sign.

KOI-7 N1

KOI-7 N1 (КОИ-7 Н1[1]) was first standardized in GOST 13052-67,[5][6][7] and later also in ISO 5427.[2] It is sometimes referred to as "koi-0" as well.[6]

Compared to ASCII and ISO 646 uppercase and lowercase letters are swapped in order to make it easier to recognize Russian text when presented using ASCII.[6]

To trim the alphabet into chunks of 32 characters the dotted Ё/ë was dropped.[6] In order to avoid conflicts with ASCII's and ISO 646's definition as DEL and its usage as EOF marker (-1) in some systems, it dropped the "CAPITAL HARD SIGN" Ъ that would have naturally resided at this location.[6]

In a Bulgarian variant the unnecessary Russian "CAPITAL YERY" Ы at code point 121 was replaced by the "CAPITAL HARD SIGN" Ъ.[6]

KOI-7 N2

KOI-7 N2 (КОИ-7 Н2[1]), like KOI-7 N1, was also standardized in GOST 13052-67.[7]

Kermit names it SHORT-KOI / short-koi.[8][9]

See also

References

  1. ^ a b c d ГОСТ 27463-87. Системы обработки информации. 7-битные кодированные наборы символов (с Изменением N 1) [GOST 27463-87. Information processing systems. 7-bit coded character sets] (in Russian). Госстандарт СССР. 1987-10-29. Archived from the original on 2016-12-03. Retrieved 2016-12-02.
  2. ^ a b c d e Sokolov, Michael (2004-01-23). "Charset name: KOI7-switched". International Free Computing Task Force (IFCTF). Archived from the original on 2016-12-03. Retrieved 2016-12-02.
  3. ^ Freed, Ned; Dürst, Martin, eds. (2013-12-20). "Character Sets". RFC2978. Archived from the original on 2016-12-03. Retrieved 2016-12-03.
  4. ^ Nechayev, Valentin (2013) [2001]. "Review of 8-bit Cyrillic encodings universe". Archived from the original on 2016-12-05. Retrieved 2016-12-05.
  5. ^ Clews, John (1988). Language Automation Worldwide - The Development of Character Set Standards (1 ed.). Sesame Computer Projects. ISBN 1-87009501-4.
  6. ^ a b c d e f Czyborra, Roman (1998-11-30) [1998-05-25]. "The Cyrillic Charset Soup". Archived from the original on 2016-12-03. Retrieved 2016-12-03. [1] [2] [3] [4]
  7. ^ a b c d Hohlov, Yu. E. "Cyrillic Information Representation in Electronic Form - Character Set (Code Page) Tables". Archived from the original on 2016-12-05. Retrieved 2016-12-05.
  8. ^ da Cruz, Frank (2010-04-02). "Kermit and MIME Character-Set Names". The Kermit Project. Columbia University, New York, USA. Archived from the original on 2016-12-03. Retrieved 2016-12-02.
  9. ^ a b "SHORT KOI (KOI-7)". Kermit. Columbia University. Retrieved 2020-06-24.

Further reading