Retrochallenge, 2005

Ethan Dicks ethan.dicks at
Tue Jun 14 19:04:19 CDT 2005

On 6/14/05, jim stephens <jwstephens at> wrote:
> worth mentioning that Tymnet used pdp 8's as did a network that
> I know ADP was running as node controllers.  I doubt that much
> of that software was ever released, and I am sure all was scrapped
> when the 8's went out the door.

And the 680/i for the PDP-10 was -8/i based... but I was thinking more
about end-user telecommunication stuff rather than embedded "under the
sheets" network infrastructure.

One issue, I think, is that most PDP-8s had a single serial port - the
console port.  You could _add_ serial ports, but except for EDUsystems
(single-CPU BASIC timesharing systems), in my experience, PDP-8 serial
ports were expensive enough (prior to, say DECmates) that machines
tended not to have anything past the console.  If DEC had added a
second serial port on the DKC8AA, things might have been different,
but they chose to load the "standard" PDP-8/a I/O board with one
console, 12-bits in, 12-bits out (which could be used as a printer
port), and programmer's front-panel interface.  Since most -8/a boxes
came with that board, it would have set the standard higher.

To tie this back into the consumer experience, it was a lightly-loaded
-8/a that David Ahl tried to push within DEC as the answer to the
surge in demand for hobbyist computers in the 1970s.  If I remember
his proposal, an entry-level machine might have a smaller chassis (4
slots?  8 slots?), a similarly scaled PSU, a 4K SRAM board, the KK8A
processor, and some sort of console, perhaps the DKC8AA, perhaps
something with fewer features at a lower end-user price.  The starting
price would have easily been right at home with what Altairs and
Imsais were sitting at, with a much higher production quality, and a
*wad* of existing 12-bit programs.  I'm not saying that the PDP-8
would have taken over the home hobby world, but the right system at
that time would have been quite popular.  With the IM6100 and IM6120
microprocessors following the KK8A close behind, things might have
been interesting.


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