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0 pointsErroneousBosh8d ago0 comments

There's a decent chance you're younger than me, but I can still read it. Coincidentally about 20 years ago I got asked to fix a bug in some PDP11 code that ran on real hardware because it was tripping up an emulated system. Nothing wrong with the emulator as such, it was just a logic bug in the program that they no longer wanted to work around.

I made the fateful mistake of saying "Sure, sounds fun, how hard could it possibly be...?"

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2 comments · 2 top-level

le-mark8d ago

Not pdp-11 but once I was tasked with fixing a c program the offshore team had failed to fix for over a year. I basically took a month off (at my desk) after I fixed it the first day. They were happy, I was a legend at that company!

amirhirsch8d ago

Love your handle

The FPGA emulator we made had to pass the xxdp test suite which was provided to me on punched tape and microfiche. The emulator had a specific test for FDIV overflow which even tested the accuracy of the partial result. None of the software emulators I tested did this. I emailed Gordon Bell who introduced me to Bob Supnkk, and we found the original flowcharts for it so I could replicate the divider logic precisely. Imagine a nuclear reactor dependent on this lol.

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