almanach graphic chipsets
2D graphic terminology
3D graphic terminology
The original CGA was built with discrete logic around an MC6845 display controller.
On the original CGA and some clones accessing the video memory during the active display time caused the display controller to miss some pixels (seen as "snow"), which is the reason many programs only accesses video memory during vertical or horizontal retrace. This is fixed in some clones and in EGA/VGA adapters.
80x25 text modes in 16colors
320x200 4color graphics modes
640x200 2 color graphics mode
TTL video interface (Red, Green, Blue and Intensity)
16KB Video RAM and 2KB ROM for 8x8 font.