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.
Well since its pretty easy to get microcode to run at 75-100 MHz or so in
current cheap FPGAs, I'd say that 10 X a 780 should be trivial...
Peter Wallace