8*24 GC incompatible with Display Enabler v2.2.2

David Cook

Active Tinkerer
Jul 20, 2023
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This is unlikely to be useful information to anyone. However, in the event someone is trying to get around an incompatibility with the Apple 8*24 GC graphics card, this may provide clues.

Running System 7.1 on a Macintosh IIci, with 32-bit addressing, correctly named 8*24 GC control panel v7.0.1, and 4 MB of GWorld memory on the card. Crashes with an address error after successfully showing the rocket ship animation at startup. Switching to 24-bit addressing works around the crash, yet sometimes the desktop pattern is drawn on window title drag bars.

Through educated trial and error, I discovered the issue was with lack of compatibility with the Display Enabler extension, v2.2.2. Removing it eliminates the problems. Why do I have this much later extension in my System 7.1 drive? I don't know. Does it happen with other versions of Display Enabler? I haven't tried.

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So there you are. The card works fine with System 7.1 and 32-bit addressing. But, later Apple software did not seem to be tested against the GC.

- David