Looking for a document regarding PDP8

Bob Smith bobsmithofd at gmail.com
Thu Apr 16 12:12:37 CDT 2020

I have posed this question to the 8lovers list, and folks seemed to
misunderstand. So let me try here.

I believe sometime in the late 70s, maybe as late as 1980, a prof
associated with UMass wrote a paper describing an extension of the
PDP8 called 8/X or 8X.
THIS IS NOT the Pre Nova/DG machine but a completely different concept.
THis is not the FPGA pdp8 implmetaton that also has an X in the name.

I believe, my memory is fuzzy, that it was a prof nnmed Stone or
Stoner (perhaps Harold S) who lead the effort and had his name on the

My fuzzy recollection was this was PDP8 with a Cache, an extension of
the instruction set, maybe to 24bits, and full compatibility with
8/e-8/a. I recall the spec citing a 10mhz (100NS) cycle time. some
sort of start up setting that would make it 8 mode or X mode on start
up, don't recall if it could switch modes while running.

I had a copy of the papers some where and it is misplaced hiding on
one of my computers and I am bout to pull out my BigMac that might
have the data in it.

THanks for any hints as to the online location,
Again, this is NOT the pdpX concept that led to the DG or the FPGA
system or the spartan 3 based system, it is just a concept paper.

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