FPGA VAX update

[Peter C. Wallace]

On Sun, 23 Oct 2005, Tim Shoppa wrote:

> 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