MS DOS Programming the Mode X Deviation

After learning about Mode 13h last time, I’ve been digging about in the ancient tomes of wisdom and discovered Mode-X. Let’s make a PC’s VGA card do odd things it was never designed for.

Watch the video


Get the code from my Github repo

When IBM created the original VGA adaptor, they never intended it to produce high colour real time graphics. However by cleverly altering the card it is possible to unlock an undocumented video mode known simply as Mode X.

I came across the Graphics Programming Black Book by Michael Abrash and printed out chapter 49 to read, which describes how this mysterious Mode-X actually works, including source code to play with.

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