FPGA VAX update

[Tim Shoppa]

Paul Koning <pkoning at equallogic.com> wrote:

> >>>>> "Michael" == Michael Sokolov <msokolov at ivan.harhan.org> writes:
>
>  Michael> Chuck Guzis <cclist at sydex.com> wrote:
>  >> If PC-based emulators are fast enough, why bother with the IC
>  >> version?
>
>  Michael> 2. A pee sea based emulator requires a pee sea.  I refuse to
>  Michael> contaminate my house with a pee sea.
>
> SIMH would run on a Mac, wouldn't it?
>
> :-)
>
> 	paul
>

SIMH will run on a VAX, in fact :-).

Getting back to FPGA's, I know of a couple FPGA implementations of
PDP-11's.  (They are mostly KDJ11 clones, but they differ in a couple
of tiny respects.)  With extreme effort in the late 90's, they managed
to make 4 FPGA's be about a factor of 2 factor on most benchmarks than
a 11/93.

By the time the FPGA implementations made it to market the PC-based
emulators were so much more cost-effective for most applications
(despite their warts of running under a host OS...)

I suspect that a FPGA implementation of a VAX would have a
performance about equal to a 11/780 if done by an average Joe.
Someone with much experience in caching/pipelining could probably
eek out a factor of 2x or 3x by pulling out all the tricks in the
book.

Tim.