monochrome display adapter (MDA)
The MDA adapter(Monochrome Display Adapter) was one of the first adapters for screen displays. It only supported monochromatic bachromatic zw. displays with up to 16 gray levels.
With this adapter no pixels could be addressed. The graphic capabilities were limited to rectangular line shapes, which could be created with the help of some special characters.
The text display was monochrome and had a resolution of 80 columns and 25 lines. All 256 ASCII characters could be displayed.