Color Graphics Adapter
CGA is the oldest standard in color displays; it was
available on the original IBM-PC shipped circa 1981.

Text: 16 colors; 80-columns by  25-lines
40-columns by  25-lines
Graphics: 2 colors; 640x200
4 colors; 320x200

Later adapters, including EGA and VGA, support the CGA
standard but provide additional screen colors and
  TECH Help! covers programming aspects of the CGA in
detail.  See CGA in the Index.