I can't vouch for the accuracy of Mel in the aforementioned story, but I can tell you that drum tuning was a *very* common practice. Other than Mel getting the sense switch backwards, all the tuning information is probable.

There are a couple of machines that have some really cool instructions. The old Data General Nova systems had an indexed fetch instruction that if the high bit was set, would use the contents of the fetched data as another index. If the high bit was set, this would repeat. It made finding the end of a linked list pretty trivial. It could also make a pretty effective endless loop. With the Nova 1200 system we... acquired... we taught it to play the "Daisy, Daisy, Give me your answer true" melody by tuning loops that made the core memory planes "sing". If I run across my 8K x 16 core memory plane, I'll take a picture and post it. Hand woven by oriental women.

Another interesting instruction was on the Control Data Corporation Cyber systems. At the request of the Atomic Energy Comission, an instruction was added that would return the number of bits set it a word (these were 60 bit words). This was used in some nuclear bomb simulation calcuations.

One free ++ to anyone who figures out what this code does, and explains why:

        and     al,00fh
        add     al,090h
        daa
        adc     al,040h
        daa
[download]

The actual instruction set is irrelevant, but that's x86 code.

--Chris

e-mail jcwren

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