AfterDawn: Glossary

Color Graphics Adapter

The Color Graphics Adapter (CGA) was the first color graphics card offered up by IBM. It was released in 1981 around the same time as the Monochrome Display Adapter (MDA) technology. It was the first color computer display standard for an IBM PC available. The card came with 16KB of video memory. It could be connected via RCA jack to an NTSC monitor or television set, with its highest resolution at 640x200 and a 4-bit color depth, driving a maximum of 16 colors.

It offered two graphics modes of 320x200 and 640x200. Each pixel can be addressed independently in 320x200 mode but only four colors can be displayed at a time. At 640x200, each pixel can be addressed independently. The mode is monochrome with a pixel aspect ratio of 1:2.4. The default colors are black and white, but the forground color can be changed to any other color of the CGA palette.

CGA wasn't as popular for business and office use as MDA, because it did not have a parallel printer port included. Also, the Hercules Graphics Card (HGC) standard gained popularity and provided good competition for CGA, especially through use of emulation drivers that made it possible to run programs written for CGA with HGC hardware. CGA was eventually succeeded by IBM's Ehanced Graphics Adapter (EGA).



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