Multi-Color Graphics Array
| Company type | Hardware feature |
|---|---|
| Industry | Computer graphics |
| Founded | April 1987 |
| Products | Video graphics hardware for IBM PS/2 Model 25 and Model 30 |
Multi-Color Graphics Array (MCGA)
The Multi-Color Graphics Array (MCGA) is a video hardware feature embedded within the IBM PS/2 Model 30, introduced in April 1987, and the Model 25, which debuted in August 1987. Notably, MCGA was never offered as a separate graphics card.
MCGA supports all display modes available on the Color Graphics Adapter (CGA), including monochrome output at 60 Hz, as well as a 256-color mode utilizing an 18-bit RGB palette capable of producing 262,144 colors at 70 Hz. The interface employs a DE-15 (15-pin analog) connector.
Although MCGA shares similarities with Video Graphics Array (VGA) by providing a 256-color mode and using the same 15-pin analog connector type, it does not support Enhanced Graphics Adapter (EGA) compatibility or the higher-resolution multi-color modes found in VGA due to inherent chipset constraints.
The commercial availability of MCGA was brief; both PS/2 Model 25 and Model 30 were phased out by 1992. Epson was the only company to replicate this adapter, incorporating it into their Equity Ie and PSE-30 systems. Meanwhile, the VGA standard, launched simultaneously, rapidly became the dominant industry standard because of its advanced graphics capabilities.
Software support
The 256-color display mode gained popularity among game developers, with many VGA titles running effectively on MCGA when restricted to its fundamental 256-color mode and avoiding VGA-specific functionalities such as multiple screen pages.
Games lacking native support for 256 colors typically defaulted to four-color CGA mode or failed to operate properly due to incompatibility with EGA video modes (, , , all limited to 16 colors). Some software from companies like Sierra On-line, Lucasfilm Games, and Microprose overcame this by enabling MCGA’s 256-color mode and choosing colors that closely matched the EGA 16-color palette while leaving unused entries blank.
Titles requiring higher resolutions were generally unsupported unless their graphics could be adapted to MCGA’s low or high monochrome resolutions (also supporting and with letterboxing). A handful of early games utilized four-color CGA graphics with palette tweaks to improve visual quality.
Output capabilities
MCGA provided:
- Template:Resx monochrome display (mode 11h)
- Template:Resx with 256 colors drawn from a palette of 262,144 colors (mode 13h)
CGA-compatible modes included:
- Template:Resx text mode featuring an 8×8 pixel font (effective ; mode 0/1h)
- Template:Resx text mode using an 8×8 pixel font (effective ; mode 2/3h)
- Template:Resx four-color mode selected from a hardware palette of 16 colors with a pixel aspect ratio of approximately 1:1.2 (mode 4/5h)
- Template:Resx two-color mode with a pixel aspect ratio near 1:2.4 (mode 6h)