In computing, a hardware code page (HWCP) refers to a

code page In computing, a code page is a character encoding and as such it is a specific association of a set of printable character (computing), characters and control characters with unique numbers. Typically each number represents the binary value in a s ...

supported natively by a hardware device such as a

display adapter A graphics card (also called a video card, display card, graphics accelerator, graphics adapter, VGA card/VGA, video adapter, display adapter, or colloquially GPU) is a computer expansion card that generates a feed of graphics output to a displa ...

printer Printer may refer to: Technology * Printer (publishing), a person * Printer (computing), a hardware device * Optical printer for motion picture films People * Nariman Printer (fl. c. 1940), Indian journalist and activist * James Printer (1640 ...

. The

glyph A glyph ( ) is any kind of purposeful mark. In typography, a glyph is "the specific shape, design, or representation of a character". It is a particular graphical representation, in a particular typeface, of an element of written language. A ...

s to present the characters are stored in the alphanumeric character generator's resident read-only memory (like

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

or flash) and are thus not user-changeable. They are available for use by the system without having to load any

font In metal typesetting, a font is a particular size, weight and style of a ''typeface'', defined as the set of fonts that share an overall design. For instance, the typeface Bauer Bodoni (shown in the figure) includes fonts " Roman" (or "regul ...

definitions into the device first. Startup messages issued by a PC's

System BIOS In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is a type of firmware used to provide runtime services for operating systems and programs and to perform hardware initialization d ...

or displayed by an

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

before initializing its own code page switching logic and font management and before switching to graphics mode are displayed in a computer's default hardware code page.

Code page assignments

In North American IBM-compatible PCs, the hardware code page of the display adapter is typically

code page 437 Code page 437 ( CCSID 437) is the character set of the original IBM PC (personal computer). It is also known as CP437, OEM-US, OEM 437, PC-8, or MS-DOS Latin US. The set includes all printable ASCII characters as well as some accented letters (di ...

. However, various portable machines as well as (Eastern) European, Arabic, Middle Eastern and Asian PCs used a number of other code pages as their hardware code page, including code page 100 ("Hebrew"), 151 ("Nafitha Arabic"), 667 ("

Mazovia Mazovia or Masovia ( ) is a historical region in mid-north-eastern Poland. It spans the North European Plain, roughly between Łódź and Białystok, with Warsaw being the largest city and Płock being the capital of the region . Throughout the ...

"), 737 ("Greek"),

850 __NOTOC__ Year 850 ( DCCCL) was a common year starting on Wednesday of the Julian calendar. Events By place Europe * February 1 – King Ramiro I dies in his palace at Santa María del Naranco (near Oviedo), after an 8-year reign ...

("Multilingual"), encodings like " Roman-8", " Kamenický", "

KOI-8 KOI-8 (КОИ-8) is an 8-bit character set standardized in GOST 19768-74. Маркелова Л. Н. Эксплуатация программоуправляемой вычислительной машины «Искра 226». — М.: М� ...

", " MIK", and others. Most display adapters support a single 8-bit hardware code page only. The

bitmap In computing, a bitmap (also called raster) graphic is an image formed from rows of different colored pixels. A GIF is an example of a graphics image file that uses a bitmap. As a noun, the term "bitmap" is very often used to refer to a partic ...

s were often stored in an

EPROM An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of programmable read-only memory (PROM) integrated circuit, chip that retains its data when its power supply is switched off. Computer memory that can retrieve stored d ...

in a DIP socket. At most, the hardware code page to be activated was user-selectable via jumpers, configuration

EEPROM EEPROM or E2PROM (electrically erasable programmable read-only memory) is a type of non-volatile memory. It is used in computers, usually integrated in microcontrollers such as smart cards and remote keyless systems, or as a separate chip d ...

s or CMOS setup. However, some of the display adapters designed for Eastern European, Arabic and Hebrew PCs supported multiple software-''switchable'' hardware code pages, also named font pages, selectable via I/O ports or additional BIOS functions. In contrast to this, printers frequently support several user-switchable character sets, often including various variants of the 7-bit

ISO/IEC 646 ISO/IEC 646 ''Information technology — ISO 7-bit coded character set for information interchange'', is an International Organization for Standardization, ISO/International Electrotechnical Commission, IEC standard in the ...

character sets such as code page 367 (" ISO/IEC 646-US /

ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...

"), sometimes also a couple of 8-bit code pages like

, 851,

852 __NOTOC__ Year 852 (Roman numerals, DCCCLII) was a leap year starting on Friday of the Julian calendar. Events By place Europe * March 4 – Trpimir I of Croatia, Trpimir I, duke (''Knyaz, knez'') of Duchy of Croatia, Croatia, an ...

, 853, 855, 857, 860, 861, 863, 865, and

866 __NOTOC__ Year 866 ( DCCCLXVI) was a common year starting on Tuesday of the Julian calendar. Events By place Byzantine Empire * April 21 – Bardas, the regent of the Byzantine Empire, is murdered by Basil the Macedonian at Miletu ...

. Printers for the Eastern European or Middle Eastern markets sometimes support other locale-specific hardware code pages to choose from. They can be selected via

DIP switch A DIP switch is a manual electric switch that is packaged with others in a group in a standard dual in-line package (DIP). The term may refer to each individual switch, or to the unit as a whole. This type of switch is designed to be used on a p ...

es or configuration menus on the printer, or via specific

escape sequence In computer science, an escape sequence is a combination of characters that has a meaning other than the literal characters contained therein; it is marked by one or more preceding (and possibly terminating) characters. Examples * In C and ma ...

Support in operating systems

When operating systems initialize their code page switching logic, they need to know but have no means to determine the previously active hardware code page by themselves. Therefore, for code page switching to work correctly, the hardware code page needs to be specified. Under

DOS DOS (, ) is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-DOS, both of which were introduced in 1981. Later compatible syste ...

and

Windows 9x Windows 9x is a generic term referring to a line of discontinued Microsoft Windows operating systems released from 1995 to 2000 and supported until 2006, which were based on the kernel introduced in Windows 95 and modified in succeeding version ...

this is accomplished by specifying the hardware code page as a parameter (hwcp) to the

device driver In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabli ...

s DISPLAY.SYS and PRINTER.SYS in CONFIG.SYS: DEVICE=…\DISPLAY.SYS CON=(type,hwcp,n, (n,m)) DEVICE=…\PRINTER.SYS PRN=(type,hwcp,n) If multiple hardware code pages are supported in OEM issues, the first hardware code page (hwcp1) in the list specifies the default hardware code page: DEVICE=…\DISPLAY.SYS CON=(type,(hwcp1,hwcp2,…),n, (n,m)) DEVICE=…\PRINTER.SYS PRN=(type,(hwcp1,hwcp2,…),n) If no hardware code page(s) are specified, these drivers default either to a dummy code page number 999 or assume the hardware code page to be equal to the primary code page (the first code page listed in COUNTRY.SYS files for a particular country with the country code either specified in the CONFIG.SYS

COUNTRY A country is a distinct part of the world, such as a state, nation, or other political entity. When referring to a specific polity, the term "country" may refer to a sovereign state, state with limited recognition, constituent country, ...

directive or assumed to be the operating system's internal default, usually 1 (US) in Western issues of DOS). In many English-speaking countries, the primary code page is either 437 (f.e. in the US) or 850 (f.e. in the UK, Ireland and Canada), so that, without specifying a different code page, the system would often assume one of these to be the corresponding device's default hardware code page as well. If a hardware code page does not match one of those with official code page assignments, an arbitrary number from the range 57344–61439 (E000h–EFFFh) for user-definable code pages or 65280–65533 (FF00h–FFFDh) for

private use code page In computing, a code page is a character encoding and as such it is a specific association of a set of printable characters and control characters with unique numbers. Typically each number represents the binary value in a single byte. (In some c ...

s could be specified per IBM CDRA to give the operating system a non-conflictive "handle" to select that code page.

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

and Hebrew MS-DOS do not use DISPLAY.SYS and PRINTER.SYS, but provide similar facilities using ARABIC.COM, HEBREW.COM, and SK.

OEM code pages

Hardware code pages are also

OEM code page Windows code pages are sets of characters or code pages (known as character encodings in other operating systems) used in Microsoft Windows from the 1980s and 1990s. Windows code pages were gradually superseded when Unicode was implemented in Win ...

s. The designation "OEM", for " original equipment manufacturer", indicates that the character set could be changed by the manufacturer to meet different markets. However, OEM code pages do not necessarily reside in ROM, but include so called prepared code pages, (aka downloadable character sets or

downloadable font Web typography, like typography generally, is the design of pages their layout and typeface choices. Unlike traditional print-based typography (where the page is fixed once typeset), pages intended for display on the World Wide Web have additional ...

s), character sets loaded as

raster font A computer font is implemented as a digital data file containing a set of graphically related glyphs. A computer font is designed and created using a font editor. A computer font specifically designed for the computer screen, and not for print ...

s into the font RAM of suitable display adapters (like

Sirius 1 Sirius Systems Technology was a personal computer manufacturer in Scotts Valley, California. It was founded in 1980 by Chuck Peddle and Chris Fish, formerly of MOS Technology and capitalized by Walter Kidde Inc. In late 1982 Sirius acquired Victo ...

Victor 9000 The name Victor or Viktor may refer to: * Victor (name), including a list of people with the given name, mononym, or surname Arts and entertainment Film * ''Victor'' (1951 film), a French drama film * ''Victor'' (1993 film), a French shor ...

, NEC APC,

HP 100LX The HP 200LX Palmtop PC (F1060A, F1061A, F1216A), also known as project ''Felix'', is a personal digital assistant introduced by Hewlett-Packard in August 1994. It was often called a Palmtop PC, and it was notable that it was, with some ...

/ 200LX/ 700LX, Persyst's BoB Color Adapter,

Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the Gr ...

' HGC+, InColor and Network Plus with

RAMFONT The Hercules Graphics Card (HGC) is a computer graphics controller formerly made by Hercules Computer Technology, Inc. that combines IBM's text-only MDA display standard with a bitmapped graphics mode, also offering a parallel printer port. ...

, and IBM's MCGA, EGA,

VGA Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the IBM PC compatible industry within three years. T ...

, etc.) and printers as well. Hence, the group of OEM code pages is a superset of hardware code pages.

Notes

References

External links