Video BIOS
Encyclopedia
Video BIOS is the BIOS
of a graphics card in a (usually IBM PC
-derived) computer.
Much the way the system BIOS provides a set of functions that are used by software programs to access the system hardware, the video BIOS provides a set of video-related functions that are used by programs to access the video hardware. The video BIOS interfaces software to the video chipset
in the same way that the system BIOS does for the system chipset.
Unlike some other hardware components, the video card usually needs to be active very early during the boot
process so that the user can see what is going on. This requires the card to be activated before any operating system
begins loading; thus it needs to be activated by the BIOS
, the only software that is present at this early stage.
Early PCs contained functions for driving MDA
and CGA
cards in the system BIOS, and those cards did not have any Video BIOS built in. When the EGA
card hit the market in 1984, the Video BIOS was introduced to make these cards compatible with existing PCs whose BIOS did not know how to drive an EGA card. Ever since, EGA/VGA and all enhanced VGA compatible cards have included a Video BIOS.
When the computer is started, some graphics cards (usually NVIDIA cards) displays its vendor, model, BIOS version and amount of graphics memory.
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
of a graphics card in a (usually IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
-derived) computer.
Much the way the system BIOS provides a set of functions that are used by software programs to access the system hardware, the video BIOS provides a set of video-related functions that are used by programs to access the video hardware. The video BIOS interfaces software to the video chipset
Chipset
A chipset, PC chipset, or chip set refers to a group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product.- Computers :...
in the same way that the system BIOS does for the system chipset.
Unlike some other hardware components, the video card usually needs to be active very early during the boot
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...
process so that the user can see what is going on. This requires the card to be activated before any operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
begins loading; thus it needs to be activated by the BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
, the only software that is present at this early stage.
Early PCs contained functions for driving MDA
Monochrome Display Adapter
The Monochrome Display Adapter introduced in 1981 was IBM's standard video display card and computer display standard for the PC. The MDA did not have any pixel-addressable graphics modes...
and CGA
Color Graphics Adapter
The Color Graphics Adapter , originally also called the Color/Graphics Adapter or IBM Color/Graphics Monitor Adapter, introduced in 1981, was IBM's first color graphics card, and the first color computer display standard for the IBM PC....
cards in the system BIOS, and those cards did not have any Video BIOS built in. When the EGA
Enhanced Graphics Adapter
The Enhanced Graphics Adapter is the IBM PC computer display standard specification which is between CGA and VGA in terms of color and space resolution. Introduced in October 1984 by IBM shortly after its new PC/AT, EGA produces a display of 16 simultaneous colors from a palette of 64 at a...
card hit the market in 1984, the Video BIOS was introduced to make these cards compatible with existing PCs whose BIOS did not know how to drive an EGA card. Ever since, EGA/VGA and all enhanced VGA compatible cards have included a Video BIOS.
When the computer is started, some graphics cards (usually NVIDIA cards) displays its vendor, model, BIOS version and amount of graphics memory.
See also
- Graphics processing unitGraphics processing unitA graphics processing unit or GPU is a specialized circuit designed to rapidly manipulate and alter memory in such a way so as to accelerate the building of images in a frame buffer intended for output to a display...
(GPU) - VESA BIOS ExtensionsVESA BIOS ExtensionsVESA BIOS Extensions is a VESA standard, currently at version 3, that defines the interface that can be used by software to access compliant video boards at high resolutions and bit depths...
(VBE) - Video Graphics ArrayVideo Graphics ArrayVideo Graphics Array refers specifically to the display hardware first introduced with the IBM PS/2 line of computers in 1987, but through its widespread adoption has also come to mean either an analog computer display standard, the 15-pin D-subminiature VGA connector or the 640×480 resolution...
(VGA)