> On Mar 23, 2020, at 9:33 AM, Robert Armstrong <b...@jfcl.com> wrote:
>
>> Ethan Dicks <ethan.di...@gmail.com> wrote:
>> Using a PDP-8 as an FEP on any VAX definitely sounds odd.
>
> The console front end for the 730 was an 8085 (just like the KS10, FWIW).
>
> The 730 was interesting in that ALL of the CPU microcode was in RAM and was
> loaded by the CFE at boot time. It was possible to locally modify the 730
> microcode, and DEC even had a set of microcode development tools for the 730.
> I've never seen them except in references.
>
> This is relevant because for years I've heard a persistent rumor that the
> PDP-8/WPS-8 group at DEC had a 730 with microcode that had been hacked to
> include a PDP-8 compatibility mode, which they used for development. It was
> faster than real -8 and supported timesharing to boot.
>
> I wonder if this is the source of the original poster's memory? Can anybody
> confirm or deny this rumor?
I can refute that. The WPS group sat right next to my first DEC group
(Typeset-11). Yes, they had a machine with extended microcode to run PDP-8
code faster. But it was an 11/60 running RSTS/E. That was in 1978; the 730
didn't exist yet back then.
paul
_______________________________________________
Simh mailing list
Simh@trailing-edge.com
http://mailman.trailing-edge.com/mailman/listinfo/simh
