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Code page 866
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<p>Code page 866 (<a href="/facts/CCSID/NKSgxNDg">CCSID</a> 866) (CP 866, "DOS Cyrillic Russian") is a <a href="/facts/Code_page/tgcBrILG">code page</a> used under <a href="/facts/DOS/sWwDXNmX">DOS</a> and <a href="/facts/OS/2/uVBl6ItP">OS/2</a> in <a href="/facts/Russia/jfkCwyxn">Russia</a> to write <a href="/facts/Cyrillic_script/0btN3oWC">Cyrillic script</a>. It is based on the "alternative code page" (<a href="/facts/Russian_language/ETXrTgHV">Russian</a>: Альтернативная кодировка) developed in 1984 in IHNA AS USSR and published in 1986 by a research group at the Academy of Science of the USSR. The code page was widely used during the DOS era because it preserves all of the <a href="/facts/Box-drawing_characters/jKI4QHeG">pseudographic symbols</a> of <a href="/facts/Code_page_437/jx27vCbb">code page 437</a> (unlike the "<a href="/facts/Main_code_page_(Russian)/4eANv1WW">Main code page</a>" or Code page 855) and maintains alphabetic order (although non-contiguously) of Cyrillic letters (unlike <a href="/facts/KOI8-R/YA7j845v">KOI8-R</a>). Initially this encoding was only available in the Russian version of MS-DOS 4.01 (1990), but with MS-DOS 6.22 it became available in any language version. </p><p>The <a href="/facts/WHATWG/WoyKwRJR">WHATWG</a> Encoding Standard, which specifies the character encodings permitted in <a href="/facts/HTML5/HBAxEAr6">HTML5</a> which compliant browsers must support, includes Code page 866. It is the only single-byte encoding listed which is not named as an <a href="/facts/ISO_8859/KFAUkAQ9">ISO 8859</a> part, <a href="/facts/Macintosh_operating_systems/EkobAhow">Mac OS</a> specific encoding, <a href="/facts/Microsoft_Windows/bwhAhuSL">Microsoft Windows</a> specific encoding (<a href="/facts/Windows-874/sQasldhr">Windows-874</a> or <a href="/facts/Windows_code_page/YKreB8a3">Windows-125x</a>) or <a href="/facts/KOI-8/EeAoW6UL">KOI-8</a> variant. Authors of new pages and the designers of new protocols are instructed to use <a href="/facts/UTF-8/xlaVHSyf">UTF-8</a> instead. </p><p>Two very similar but not identical encodings are standardised in <a href="/facts/GOST/Ith9dFHs">GOST</a> R 34.303-92 as KOI-8 N1 and KOI-8 N2 (not to be confused with the original <a href="/facts/KOI-8/EeAoW6UL">KOI-8</a>). </p>