Have You Heard Of MCGA?

In the world of PC graphics, the early standards followed the various video cards of the day. There was MDA, familiar through the original text-based DOS prompt, CGA, then EGA, and the non-IBM Hercules along the way. Finally in 1987 IBM produced the VGA, or Video Graphics Array standard for their PS/2 line of computers, which became the bedrock on which all subsequent PC graphics cards, even those with digital outputs, have been built. It’s interesting then to read an account from [Dave Farquhar] of the other now-forgotten video standard that made its debut with the PS/2, MCGA, or Multicolor Graphics Array. This was intended as an entry-level graphics system to compete with the more multimedia-oriented home computers of the day such as the Commodore Amiga and Atari ST.

Offering 320×200 graphics at 256 colors but only two colors at 640×480 it’s difficult to see how it could have been a viable competitor to the Amiga’s 4096-color HAM mode, but it did offer the ability to drive an RGB monitor through its VGA-like socket. The story goes that IBM intended it to provide an upgrade incentive for PS/2 customers to buy a more powerful model with VGA, but in the event a host of third-party VGA-compatible cards emerged and allowed more traditional ISA computers from third parties to retain a competitive edge and eventually sideline the PS/2 line entirely.

We called time on VGA back in 2016, and it’s fair to say that it’s disappeared from PC hardware since then even if much of its technologies still lurk within. It’s pleasing to see though that it remains a stalwart of hacked-together display interfaces, with efforts such as this 7400-based VGA card continuing to impress us.

21 thoughts on “Have You Heard Of MCGA?

  1. What makes me laugh… OK, scoff, is when people to this day try to use some of these ridiculous monikers to describe resolutions. WTF is “WXGA?” Oh, and by the way, do you have EXTENDED or EXPANDED memory in your 386 computer?dkd

  2. Although I was never a PC fan, MultiColor Graphics Array video always looked the most fun to me, because it offered 256 colours from the largest palette available. Also, because a British company Inmos designed the palette chips.


    What’s so great about Inmos? They produced a radical multi-processing CPU called the Transputer which ran an inherently parallel language called Occam (as in Occam’s razor) and it was possible to easily transform the code to run on a vast array of parallel processors. Basically, multicore CPUs could have been the norm, since the early 90s!


  3. >Offering 320×200 graphics at 256 colors but only two colors at 640×480 it’s difficult to see how it could have been a viable competitor to the Amiga’s 4096-color HAM mode

    By the fact that it isn’t “Hold-And-Modify” where you cannot set a pixel to an arbitrary color value. You can only change the red, green or blue value between adjacent pixels so only every third pixel is actually independent. It’s a horrible horrible hack that only really works “right” for static images – or rather, you could mask the artifacts caused by it with cleverly designed graphics.

    The Amiga got away with it because the graphics system didn’t work with a simple frame buffer. It had a “playfield” and then you had separate animated sprites which would be drawn on top of the playfield by a different mechanism, so you could kinda-sorta cheat that you have 4096 colors when actually you had 32.

    1. Sorry, 16 actual palette colors, from which you could then shift the red, green, or blue value for the pixel to the right. What comes next was obvious: to reach the desired colors with fewer value shifts, you would use another special chip to change the palette registers every scan line, so the right 16 colors were available where needed. This was called the Sliced or SHAM display mode.

      There is a certain type of a person that in their time would buy an original iPhone (before App Store), an original Tesla Roadster, an Amiga, and call them superior technology because they can turn a gimmick.

  4. Just wanted to add that VGA is still very much alive in the enterprise computing world. Even the most cutting edge of Dell or HP servers still come equipped with VGA ports for video.

    1. As I recall, the previous article was really about the VGA connector disappearing. Which isn’t true either, but I suspect some shift to the other connectors.

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