GEM character set
Language(s)English
Created byDigital Research
Based oncode page 437
Other related encoding(s)Atari ST character set, Ventura International character set

The GEM character set is the character set of Digital Research's graphical user interface GEM on Intel platforms. It is based on code page 437, the original character set of the IBM PC.

Like codepage 437, it aligns with ASCII codepoints 32–126, and has additional codepoints including letters with diacritics and other symbols. It differs from code page 437 in using other dingbats at code points 0–31, in exchanging the box-drawing characters 176–223 for international characters and other symbols, and exchanging code point 236 with the symbol for line integral. However, GEM is more similar to code page 865, because the codepoints of Ø and ø match the codepoints in that codepage.

A slight adaptation for Ventura Publisher is the similar Ventura International character set, it has code points 0-31, 127, and 218-255 empty, and has swapped ¢ and ø and has also swapped ¥ and Ø (to match code page 437 more).

The GEM-derived file manager ViewMAX, which shipped with some versions of DR DOS as a DOSSHELL replacement, does not use the GEM character set, but loads its display fonts from DOS .CPI files[1][2][3][4][5][6] depending on the system's current code page.

Character set

The following table shows the GEM character set. Each character is shown with a potential Unicode equivalent, although some codes do not have a unique Unicode equivalent; the correct choice may depend upon context.

GEM character set[7][8][3][9]
0 1 2 3 4 5 6 7 8 9 A B C D E F
0x NUL ⇧[a] ⇩[a] ⇨[a] ⇦[a] ◼[a] 🗗[a] ◆[a] ✓[a] 🕒︎ 🔔︎ ♪ ▴ ▾ ▸ ◂
1x ► ◄ ⧓[a] ▂[a] [b] § ↕ ↨ ↑ ↓ → ← ∟ ↔ ▲ ▼
2x  SP  ! " # $ % & ' ( ) * + , - . /
3x 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
4x @ A B C D E F G H I J K L M N O
5x P Q R S T U V W X Y Z [ \ ] ^ _
6x ` a b c d e f g h i j k l m n o
7x p q r s t u v w x y z { | } ~ ⌂
8x Ç ü é â ä à å ç ê ë è ï î ì Ä Å
9x É æ Æ ô ö ò û ù ÿ Ö Ü ø £ Ø ¤ ƒ
Ax á í ó ú ñ Ñ ª º ¿ “ ” ‹ › ¡ « »
Bx ã õ ¥ ¢ œ Œ À Ã Õ § ‡ † [b] © ® ™
Cx „ … ‰ • – — ° Á Â È Ê Ë Ì Í Î Ï
Dx Ò Ó Ô Š š Ù Ú Û Ÿ ß
Ex α β Γ π Σ σ µ[c] τ Φ Θ Ω[d] δ[e] ∮ ɸ ∈ ∩
Fx ≡ ± ≥ ≤ ⌠ ⌡ ÷ ≈ ° ∙ · √ ⁿ ² ■ ∅
  Different than code page 437
  1. ^ a b c d e f g h i j 1–8 and 18-19 are used in GEM AES user interface elements such as icons for closing, resizing and maximizing windows.
  2. ^ a b Code point 20 (1416) is an unfilled paragraph sign, while code point 188 (BC16) is a filled paragraph sign. This distinction does not exist in Unicode, so both are mapped to U+00B6 PILCROW SIGN here.
  3. ^ 230 (E6hex) is both the micro sign (U+00B5, µ) and the Greek lowercase mu (U+03BC, μ).
  4. ^ 234 (EAhex) is both the ohm sign (U+2126, Ω) and the Greek uppercase omega (U+03A9, Ω). (Unicode considers the ohm sign to be equivalent to uppercase omega, and suggests that the latter be used in both contexts.[10])
  5. ^ 235 (EBhex) is the Greek lowercase delta (U+03B4, δ), but it has also been used as a surrogate for the Icelandic lowercase eth (U+00F0, ð) and the partial derivative sign (U+2202, ∂).

See also

References

  1. ^ Paul, Matthias R. (2001-06-10) [1995]. "Format description of DOS, OS/2, and Windows NT .CPI, and Linux .CP files" (CPI.LST file) (1.30 ed.). Archived from the original on 2016-04-20. Retrieved 2016-08-20.
  2. ^ Elliott, John C. (2006-10-14). "CPI file format". Seasip.info. Archived from the original on 2016-09-22. Retrieved 2016-09-22.
  3. ^ a b Elliott, John C. (2006-09-03). "Codepage-related software". Seasip.info. Archived from the original on 2016-11-08. Retrieved 2016-11-09.
  4. ^ Brouwer, Andries Evert (2001-02-10). "CPI fonts". 0.2. Archived from the original on 2016-09-22. Retrieved 2016-09-22.
  5. ^ Haralambous, Yannis (September 2007). Fonts & Encodings. Translated by Horne, P. Scott (1 ed.). Sebastopol, California, USA: O'Reilly Media, Inc. pp. 601–602, 611. ISBN 978-0-596-10242-5.
  6. ^ MS-DOS Programmer's Reference. Microsoft Press. 1991. ISBN 1-55615-329-5.
  7. ^ "WordPlus GEM character set". WinWorld. Archived from the original on 2017-01-23. Retrieved 2017-01-23.
  8. ^ Lineback, Nathan. "GEM 3.11 Screen Shots". Nathan's Toasty Technology page. Archived from the original on 2019-11-18. Retrieved 2016-08-01.
  9. ^ Elliott, John C. (2006-09-04). "Fonts for Intel GEM - System Fonts". Seasip.info. Archived from the original on 2017-02-06. Retrieved 2016-09-22.
  10. ^ The Unicode Consortium (2003-05-21). "Chapter 7: European Alphabetic Scripts" (PDF). The Unicode Standard 4.0. Addison-Wesley (published August 2003). p. 176. ISBN 0-321-18578-1. Retrieved 2016-06-09.
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