MCGA was the high-end graphics standard used by
IBM in their
PS/2 range of computers.
MCGA screen modes included
320x200x256 and
640x480x2. It was not compatible at all with
VGA or
EGA, although some early VGA
DOS software included support for it. MCGA must have been developed at some time in the mid-Eighties. It allowed me to use
DeluxePaint 2 in all its 256-colour glory way back in
1989 (the machine - my dad's - came with MCGA support in
1987 but there was practically no software that supported it, and in fact, the IBM dealer didn't even know that the machine had this functionality). It also allowed me to run
Night Shift and
Prince of Persia, really, really slowly.
According to Michael Abrash's book, MCGA on the PS/2 Model 30 (the machine my Dad has) was the reason that VGA generally only offers 320x200 in 256 colours: VGA could go as high as 320x400x256, but MCGA, having less memory, could not.