Graphic modes

The graphics adapter that equips a PC determines the quality of text and images one can show on the display screen:

· the CGA (Colour Graphics Adapter) adapter is cheap and offers a rather poor quality; 320x200 pixels and four colours, or 640x200 pixels in black and white; WINDOWS does not support this type of graphics adapter;

· the MCGA (Multi Colour Graphics Adapter) adapter is offered by IBM with 320x200 pixels and 256 colours out of 256,000; or 640x480 pixels and two colours (black and white);

· the EGA (Enhanced Graphics Adapter) adapter offers 640x350 pixels with 16 colours out of 64;

· the VGA (Video Graphics Array) adapter is offered by IBM with 640x480 pixels with 16 colours out of 256,000 (262,144), or 64 grey shades on a mono display;

· the VGA8 adapter is offered by IBM with 360x480 pixels and 256 colours out of 256,000; it works on VGA display screens;

· the 8514/A adapter if offered by IBM with 640x480 and 256 colours, or 1024x768 and 256 colours when the application supports it;

· the XGA (Extended Graphics Adapter) adapter is offered by IBM with 1024x768 pixels and 256 colours out of 256,000;

· the SVGA (Super VGA) adapter is offered by all other manufacturers and works with 1024x768 pixels, with 256 colours.

Quality images recorded with a certain resolution can be converted by certain software into a lower resolution; the reverse is unfortunately not possible. Compatibility always exists downwards: a SVGA screen may show a VGA image, but the reverse is not possible.