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Comment Re:One stray ; burned a week... (Score 1) 231

My worst bug ever was a third order bug (A changes B, which later results in C being changed, which finally manifests as visible defect D).

This occurred four hours into a full bore system integration test.

This was using a Z8000 CPU We wound up having to put an ICE on the thing, but because of all the radio signals, the ICE cable had to go into the case, the gap sealed with foil, and the ICE cable also wrapped in foil. Then we recorded (using analog cassette tape) all the FSK radio signals, and play them back into the boxen.

The Z8000 compiler used jump tables and the CPIR (compare/increment/repeat) instruction to implement switch statements. I was the kernel guru, and the error appeared out of a kernel error message. We didn't have any memory protection.

What happened was that someone ignored a return value, and wound up indexing something by -1, which eventually wound up modifying a switch table...

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