video display standard
IBM and others have introduced a bewildering plethora of graphics and text display standards for IBM PCs. 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 had to support the major IBM graphics standards and many non-IBM, proprietary standards for displays. Either software vendors provided display drivers or display vendors provided drivers for the software package. In either case, switching software or switching display systems was 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.