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Old September 21st 03, 06:51 AM
Geoffrey G. Rochat
 
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kenneth scharf wrote in message
...
Does anybody know where I can get a Harris or Intersil
HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)?

I used to work for Digital, and thought it would be an interresting

project
to homebrew a PDP-8 system. I have a T11 microprocessor chip in the

junbox
someplace, so a PDP-11 system is also a possibility.



In fact, there is a fellow who sells kits and parts for the SBC6120, which
is a build-your-own PDP-8 based on the IM6120 chip:

http://www.sparetimegizmos.com/Hardware/SBC6120-2.htm

And this fellow has an add-on for the SBC6120:

http://www.jkearney.com/sbc6120/iob6120.htm

Also, IM6100 chips show up on eBay from time to time.

PDP-8 documentation may be found at Al Kossow's site:

http://www.spies.com/~aek/pdf/dec/pdp8/

And at Dave Gesswein's site:

http://www.pdp8.net

Also, Bob Supnik's SIMH retrocomputing simulator supports the PDP-8. SIMH
is hosted at Tom Shoppa's Trailing Edge site, currently down due to the
effects of Isabel:

http://simh.trailing-edge.com

To those of you who chuckle at the OP's questions, I've got a PDP-8/A
sitting about 5ft to my right as I type this, and a another in the basement,
right next to a PDP-8/E, a VT78 (based on the IM6100) and a DECmate II
(based on the IM6120). Just today I was at one place with a third PDP-8/A
which I refurbished a few months ago, a working PDP-8/E, a PDP-8/L in need
of serious help, 3 PDP-12s (essentially PDP-8/Is with added A/D and D/A
I/Os), several DECmates and a LINC-8. Today I also stopped by a place with
a several more DECmates and a PDP-8/L that I and a cohort rescued from the
defunct United Electronics tube factory in Newark, NJ this past spring.
PDP-8 Disease is incurable. Once infected you're happily chronic for life.

You can do an awful lot on a computer with only 8 instructions that can
directly address a mere 256 12-bit words at a time - if you're willing to
think a little bit. PDP-8s are to computers what regens are to radios:
Obsolete, but amazing for what they can do with so little, and a tremendous
pile of fun to play with. In essence they're the spirit of QRP operation as
applied to computers.

Geoffrey G. Rochat
Vice President, Rhode Island Computer Museum (www.osfn.org/ricm)
Member, RetroComputing Society of Rhode Island (www.osfn.org/rcs)