MDA or MDPA
               Monochrome Display Adapter
MDA is the oldest display standard; it was available on
the original IBM-PC shipped circa 1981 (sometimes called
MDPA since the original adaptor also provided a parallel
printer port).

    Text: 2 colors+underline; 80-columns by 25-lines
                              40-columns by 25-lines
Graphics: none

A common variant is the "Hercules" or "MonoGraphics"
display adapter which supports black-and-white graphics.