Multi-Color Graphics Array


The Multi-Color Graphics Array or MCGA is a video subsystem built into the motherboard of the IBM PS/2 Model 30, introduced on April 2, 1987, and Model 25, introduced later on August 11; no standalone MCGA cards were ever made.
The MCGA supports all CGA display modes plus 640×480 monochrome at a refresh rate of 60 Hz, and 320×200 with 256 colors at 70 Hz. The display adapter uses a DE-15 connector. The MDA monochrome text mode is not supported.
MCGA is similar to VGA in that it had a 256-color mode and uses 15-pin analog connectors. The PS/2 chipset's limited abilities prevents EGA compatibility and high-resolution multi-color VGA display modes.
The tenure of MCGA was brief; the PS/2 Model 25 and Model 30 were discontinued by 1992, and no manufacturer produced a clone of this display adapter except for Epson Equity Ie, since the VGA standard introduced at the same time was considered superior.

Software support

The 256-color mode proved most popular for gaming. 256-color VGA games ran fine on MCGA as long as they stuck to the basic 320×200 256-color mode and didn't attempt to use VGA-specific features such as multiple screen pages.
Games lacking support for 256-color graphics were forced to fall back to four-color CGA mode due to the incompatibility with EGA video modes. Some games, including point-and-click adventures from Sierra On-line and Lucasfilm Games, as well as simulation and strategy titles from Microprose solved this problem for low-resolution titles by supporting MCGA in its 320×200 256-color mode and picking the colors most resembling the EGA 16-color RGB palette, while leaving the other available colors in that mode unused. Higher resolution titles were often unsupported unless graphics could be converted into either MCGA low or high in an acceptable fashion. An alternative approach used by a small number of games was to use 4-colour CGA assets but make use of the adaptor's ability to freely change each of the palette colours for a slightly enhanced appearance.

Output capabilities

MCGA offered:
CGA compatible modes: