> On Jul 9, 2020, at 10:40 PM, Johnny Billquist <b...@softjar.se> wrote: > > On 2020-07-10 04:37, Don North wrote: >> On 7/9/2020 6:25 PM, Bob Supnik wrote: >>> Yes, the PDP11 Architecture Handbook was a post-facto effort. The J11 was >>> finished; DEC did not intend to do another PDP11 processor. (I wrote a spec >>> for one, primarily as an exercise in trying to do a different microcode >>> structure than the PLA/ROM of the LSI11/F11/J11, but I lost it.) The only >>> formal part of the PDP11 architecture was the Commercial Instruction Set >>> extension, DEC STD 168, which was only implemented by the F11 and the 11/44. >> AND the PDP-11/74 CIS option, I might add. Fully implemented, never sold. > > Not to mention that the 11/74 in itself was fully implemented, but never > sold... Not even the 11/70MP...
Were there actually two prototypes called 11/74? I know the MP machine, which the RSX-11 development team owned. And in Merrimack (home of RSTS and some of the compiler teams) there was an 11/74 with CIS, for COBOL. But that one wasn't an MP machine. Perhaps a coincidence, I don't have a real memory either way. paul _______________________________________________ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh