hello,

> Yes, actually I have. I did it as a feasibility study a few years ago
> for someone who wanted to explore the possibility of building a PCI-based
> VAX. It is possible, but there are some not-so-obvious pitfalls and a
> few compromises that must be made. Among them, for example, is that 
> even though the NV5 is pin-compatible, the Alpha has a much larger
> physical address range. The I/O is distributed throughout the address
> range. You need to make certain the VAX can touch all the important
> I/O areas, which is a bit tricky.


i'd expect that here would be plenty of this kind of complication.. 
> 
> >Next, assuming this is possible, how on earth could one go
> >about getting one's hands on an NVAX5 chip in this day and age??? is this
> >a pipe dream? 
> 
> Yes, this is a pipe dream. DEC has manufactured all of the NV5s that are
> ever going to be manufactured and has stockpiled them for their use. They
> are unwilling to sell them and, when they do, the price is outrageous
> (consider that every chip they sell you is one less high-margin VAX
> they can build). It is simply not cost-effective.

(so basically the price of an NV5 chip is the same as the price of one of
the few remaining VAXstations and a few minutes to pull it ;-)

i was out on a limb positing that such things can be bought, so i expected
something like this.. is it true that FAB6 was busy cranking out NVAX
chips round the clock right before the sale to intel? 

> I have a nice little 32-bit FORTH that loads into the NV5's cache from
> the serial ROM then bit-bangs the serial ROM I/O leads to provide a
> console. It is capable of living entirely within the cache, and is even
> intelligent enough to move itself out of the way when it's time to test
> a chunk of memory (a good thing too; I never would have figured out one
> of the obscure pitfalls without that particular feature).

8^) 
cool.. 

(what the particular pitfall?? ) 


> 
> Not as far as I know. I've never actually designed around the 21164 bus,
> but I understand that it is quite different from the 21064/NV5 bus.

thats what i thought... just wondering if i was wrong:) 

still dreaming of a really fast under 1Kw VAX,
Isildur