display standard

hardware IBM and others have introduced a bewildering

plethora of graphics and text display standards for IBMPCs. The standards are mostly implemented by plugging in a

video display board (or "graphics adaptor") and connecting

the appropriate monitor to it. Each new standard subsumes its

predecessors. For example, an EGA board can also do CGA

and MDA.

With the PS/2, IBM introduced the VGA standard and built

it into the main system board motherboard. VGA is also

available as a plug-in board for PCs from third-party vendors.

Also with the PS/2, IBM introduced the 8514 high-resolution

graphics standard. An 8514 adaptor board plugs into the PS/2,

providing a dual-monitor capability.

Graphics software has to support the major IBM graphics

standards and many non-IBM, proprietary standards for

high-resolution displays. Either software vendors provide

display drivers, or display vendors provide drivers for the

software package. In either case, switching software or

switching display systems is fraught with compatibility

problems.

Display Resolution Colours Sponsor Systems

MDA 720x350 T 2 IBM PC

CGA 320x200 4 IBM PC

EGA 640x350 16 IBM PC

PGA 640x480 256 IBM PC

Hercules 729x348 2 non-IBM PC

MCGA 720x400 T

320x200 G 256 PS/2

VGA 720x400 T

640x480 G 16

SVGA 800x600 16 VESA

XVGA 1024x768 256 (IBM name: 8514)

T: text, G: graphics.

More colours are available from third-party vendors for some

display types.

See also MDA, CGA, EGA, PGA, Hercules, MCGA,

VGA, SVGA, 8514, VESA.