Code page 850 (CCSID 850) (also known as CP 850, IBM 00850,[2] OEM 850,[3] DOS Latin 1[4]) is a code page used under DOS operating systems[a] in Western Europe.[5] Depending on the country setting and system configuration, code page 850 is the primary code page and default OEM code page in many countries, including various English-speaking locales (e.g. in the United Kingdom, Ireland, and Canada), whilst other English-speaking locales (like the United States) default to the hardware code page 437.[6]
Code page 850 differs from code page 437 in that many of the box-drawing characters, Greek letters, and various symbols were replaced with additional Latin letters with diacritics, thus greatly improving support for Western European languages (all characters from ISO 8859-1 are included). At the same time, the changes frequently caused display glitches with programs that made use of the box-drawing characters to display a GUI-like surface in text mode.
After the DOS era, successor operating systems largely replaced code page 850 with Windows-1252,[b] later UCS-2 and UTF-16,[c] and finally UTF-8. However, legacy applications, especially command-line programs, may still depend on support for older code pages.
Each non-ASCII character appears with its equivalent Unicode code-point. Differences from code page 437 are limited to the second half of the table, the first half being the same.
In 1998, code page 858 (CCSID 858)[11] (also known as CP 858, IBM 00858, OEM 858[3]) was derived from this code page by changing code point 213 (D5hex) from a dotless i ⟨ı⟩ to the euro sign ⟨€⟩ U+20AC.[12][13][14] Unlike most code pages modified to support the euro sign, the generic currency sign at CFhex was not chosen as the character to replace (compare ISO-8859-15 (from ISO-8859-1), code pages 808 (from 866), 848 (from 1125), 849 (from 1131) and 872 (from 855), ISO-IR-205 (from ISO-8859-4), ISO-IR-206 (from ISO-8859-13), and the changes to MacRoman and MacCyrillic).
Instead of adding support for the new code page 858, IBM's PC DOS 2000, also released in 1998, changed the definition of the existing code page 850 to what IBM called modified code page 850 to include the euro sign at code point 213.[15][16][17][18][19] The reason for this might have been due to restrictions in MS-DOS/PC DOS, which limited .CPI files to 64 KB in size or about six codepages maximum. Adding support for codepage 858 might have meant to drop another (e.g. codepage 850) at the same time, which might not have been a viable solution at that time, given that some applications were hard-wired to use codepage 850. More recent IBM/MS products implemented codepage 858 under its own ID.
Code page 1108 (DITROFF Base Compatibility) is an extension of this codepage which alters some code points in the range 0–32 from their definitions in Code page 437.[20]DITROFF (device independent troff) is an intermediate format of the standard Unix text formatter Troff.
Code page 1109 (DITROFF Specials Compatibility) contains characters not available in Code page 1108.[21]
Code page 1044 (CCSID 1044) is a code page used under DOS to use in shipping labels. It is a subset of Code page 850.
Each character appears with its equivalent Unicode code-point.[22]
Code page 1034 (CCSID 1034) is a code page used under DOS to use in shipping labels. It is the second set used after code page 1044.[23] This is the code page with the fewest characters.
Each character appears with its equivalent Unicode code-point.[24]
Code page 906 (CCSID 906) is a code page used by the IBM 3812, like code page 907. It is a modification of Code page 850.[25]
Each character appears with its equivalent Unicode code-point. [26]
The new official ID for the Multilingual "codepage 850 with EURO SIGN" is 858, not 850. IBM will switch to use 858 instead of their 850 variant with future issues of their products. […] I can only guess why they didn't add 858 to their EGAx.CPI, COUNTRY.SYS, and KEYBOARD.SYS files in PC DOS 2000. Many third-party applications are designed to work with 850 and didn't know about 858 at the time PC DOS 2000 was released, so it's easier for everyone, but unfortunately it's not compatible. […] As explained above, COUNTRY.SYS and KEYBOARD.SYS contain only two codepage entries for a given country in Western issues of DOS. (In Arabic and Hebrew issues there can be up to 8 codepages for one country, in theory there is no limit below the range of allowed codepages 1..65534). […] The problem is that removing support for 850 might have caused compatibility problems with applications which are hard-wired to use 850. Adding 858 as a third choice to all the files would have increased the file and table sizes significantly. The COUNTRY.SYS file parser in MS-DOS/PC DOS IO.SYS/IBMBIO.COM sets aside a 6 Kb (for DOS 6) scratchpad to load all the info. This allows a maximum of 438 entries in a COUNTRY.SYS file to be accepted, otherwise you will get the message "COUNTRY.SYS too large.". The NLSFUNC parser does not have this limitation, and the file parsers in DR-DOS (kernel and NLSFUNC) also do not know of such a restriction. Older issues of MS-DOS/PC DOS even had a 2 Kb buffer for a maximum of 146 entries.
[…] one could also create custom .CPI files in the traditional FONT style without difficulties, but you could only store up to […] six codepages in such a file if it should be useable by MS-DOS/PC DOS (some OEM issues and NT can handle files larger than 64 Kb, but MS-DOS/PC DOS can not).(NB. Based on fd-dev post [1].)