Re: emc for wire edm control

[Jon Elson <elson-at-pico-systems.com>]

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>>I have several old 2-axis "blue" Andrew 330's and 630's with servos,
>>these macines do backup during short, a DEC PDP8\a is the heart of the
>>axis motion on this beauty.
>>Does anyone know how to dis-assemble pdp8\a a code???
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Yes, I could probably do this.  The PDP-8 had some wierd
stuff having to do with memory pages, and the "low page".
But, I'm pretty sure I could dig up the instruction set and
make a disassembler for it.  I got an

Allen-Bradley 7320 a couple years ago, and then had to find somebody on the
net to copy the executive tapes for it.  I then had to go in and patch the
code for my encoder resolution, and get rid of a tandem axis setup for the
particular machine that executive was made for.  I first put together a
"BTR" to connect a PC to the paper tape reader and the PTR port on
the CNC control.  I then read in all the tapes, figured out how their
binary loader format worked, and wrote a disassembler for that machine's
instruction set.

Gee, I'm not sure it really makes a lot of sense to reverse engineer 
something
that far out of date.  I have to tell you, that I only deciphered about 
5% of the
A-B 7320's executive, the particular functions that I had to hack into. 
 Obviously,
the severely limited memory on the PDP-8 (unless they used all the memory
expansion available on the later 8A models) would force the code to be
simpler than the 64 KBytes on my A-B.

Jon

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