On Thursday 15 March 2007 03:45, CRC wrote:
On Thu, 15 Mar 2007 00:36:59 -0400, Patrick Finnegan
<pat at computer-
refuge.org> wrote:
The VAXstation 3520 (and 3540) are dual and quad
processor pedestal
vaxes
(BA213-sized chassis) that DEC breifly tried to sell, with a weird
(only
used on those models) processor/memory bus called the "M bus". I
was hoping that I could get more than 4 CPUs to function in the
machine, and
after a lot of effort (module order did matter!), I got some
encouraging
results. I bet no one else here can claim that they've got a
"VAXserver
3560"...
[...hack...]
Okay, you have my interest. I assumed you sacrificed the graphics
card slots for the additional CPU and memory. Pray tell the order.
I'm running a 3540 with the second box kept as running spares less
the processors and memory.
The order from left to right is:
QBUS board - Memory - CPU - CPU - Memory - CPU - I/O board. Note that
the video board has to be pulled, and the rightmost two slots (with the
2nd and 3rd video boards) aren't *real* MBus slots, don't try plugging
card into them. I managed to break my video board by plugging it into
the wrong slot. :(
Also, since I had two different versions of firmware (1.1 and 1.2), the
board with the 1.1 version of the firmware had to go in the farthest
right CPU slot, or else it wouldn't bring up all of the CPUs; in fact,
if it was in the first CPU slot, then the system wouldn't come up at
all, and would hang with "D" on the system LED display. I'm gonna try
blowing a pair of new EPROMS with the 1.2 firmware to upgrade the 1.1
firmware CPU, at work today, and see if that fixes the problems I've
seen.
If you're OK with just one memory board, you might be able to squeeze 4
CPU boards into one box. I just don't have enough to try that yet.
At one time, after one beer too many, I had thoughts
of repopulating
my second box to a 3540 level and building a M-buss extender to come
up with a 3580. However, the hangover and the light of day squashed
those thoughts :-))
MBus is different than QBUS or UNIBUS, in that each slot is (to some
extent) individually accessible. So, it'd probably be difficult at best
to build an MBus "extender". Though, I have thought of that before, as
well. :)
Pat
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