[Simh] Simh Digest, Vol 198, Issue 16

[Paul Koning]

> On Jul 9, 2020, at 10:40 PM, Johnny Billquist <bqt at 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