I thought so too. But what about SPX? Can it go into a
pre-M76 VS3100? And what about VS2K SPX? (It would of course
be very silly in practice, but I'm talking in principle.)
SPX will go into KA42s - although I don't know for sure whether
it was ever sold and supported. It will probably plug into a
VS2K but I have no idea whether it will work (or whether anything
would run on it without more code being written).
So I thought that KA42 had one big CDAL-to-EDAL bridge
upfront and the rest of the system except memory was EDAL.
But I could be wrong, maybe different subsystems have their
own independent connections to CDAL.
You are probably right - I just threw in "as necessary" because
I don't have a KA42 block diagram handy (in fact, I may not have
one at all - there is not much info floating around on these
and the early UVAX 3100 systems).
But if KA42 indeed has one big CDAL-to-EDAL bridge
upfront,
the million dollar question becomes: why did the VS4000 M90
dev team toil to design their own CDAL-to-EDAL bridge (CEAC)
if there already was one? The only plausible explanation I
could come up with is that perhaps on KA42 the CDAL-to-EDAL
bridge was inseparably integrated with the memory controller.
I don't know why they rolled their own. Given that they used
or modified existing designs where possible, I assume that there
were good reasons. Perhaps the existing design was too slow or
took up too much room (this latter consideration was definitely
very important for the -90).
BTW, I have never found any references to a technical
manual
for VS3100 (any
model) or for the corresponding early MV3100 models. It looks
like one never existed. Do you have any more info?
No - and I could never find any even while I was inside
DEC. There must have been *some* such documentation
but it was nowhere I could find.
Does KA43 have memory on CDAL or on RDAL? I once had
one in
my hands and when I looked on the board to see what chips it
There's not a lot of technical info on the KA43 either!
Yeah, maybe that was the change. (Was that a typo or
was
EDAQL a chip converting EDAL to SPX's internal bus?)
Typo.
http://www.research.compaq.com/wrl/DECarchives/DTJ/DTJ402/DTJ402SC.TXT
But it talks about the X aspects of it and says nothing about VXT2000
hardware.
Yes, I've read that one and it's not the one. I was sure that there was
an article describing the VXT2000 itself, but I guess since I cannot
find it either on the web or in my docs, I must have
imagined it. Oh well.
Antonio
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Antonio Carlini arcarlini(a)iee.org