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
the appropriate monitor to it. Each new standard subsumes its
predecessors. For example, an
EGA board can also do
CGAWith the
PS/2, IBM introduced the
VGA standard and built
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
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.