there is a reason... PDP-8s were the most prolific and
the production
nubers were in teh low tens of thousands and many still serve.
I suppose the time to grab them was the early 1980s (that is when I
grabbed my two machines, but not from scrapyards).
The 18bit
stuff were few to start with and hard as hell to expand so they faded
away.
I still lust for a PDP-15 (I saw one at the Smithsonian Institution, as
some sort of fingerprint anaylzer display. I do not think it is
functional). I know one will show up some time, either in a junkyard,
barn, basement, etc.
William Donzelli
william(a)ans.net