Similar to the 11/70 in some ways, yes (a high-speed private memory bus), but very different in others (a second UNIBUS allowing another PDP-11 access to shared memory - nothing like that on the 11/70). Like I said, this is in the 1971 11/45 Processor Handbook (which I think is the first edition; I've never seen an earlier one), so I think it's original. I guess that manual's not online; if you'd like, I can scan that diagram and put it online. Noel