> The PDP-11 and the PDP-12 have nothing in common, and are very different
> sizewise as well. The PDP-12 was a 12-bit architecture evolving from the
> PDP-8 (which in turn came from the PDP-5). This series is definitely
> RISCy, even though it was developed in the '60s. The PDP-11 is rather
> CISCy.
As I recall the PDP-12 was a combination computer having both PDP-8
processor and a Link processor.  The PDP-12 we had "when I was a student"
had 8k 12 bit words of memory and a 32k word swaping disk (8 fixed
heads) and ran a 7 user system with focal.  While running one user in one
4k word bank it was swaping the previous user out or next user in on the
other 4k word bank of memory.  The interpeter, program and data had to fit
all in 4k 12 bit words.  This worked remarkably well with 110 baud
teletypes.

I remind my students of the "good old days" when they start complaining
about lack of performace of todays systems.

johnh...