The 730, on the other hand, was something of a wimp.
I was offered one
when Sorcim dumped theirs and I refused it. Microprocessor technology
was catching up too fast to consider giving it a home.
I'm the opposite (as usual). I turned down an 11/750 and actively looked
for (and eventually found) an 11/730. My views on these amachiens are :
11/780. Beautiful, but alrge and power-hungry. I'd love one, but only if
I had somewwhere to put it
11/750. All custom gate arrays make it hard to understand and even harder
to repair. Not a amchine I would ever want ot run
11/730. To fit a VAX processor onto 3 hex-heightcards using only stnadard
ICs [1] is a hack. It;'s postly (unprotected) PALs. There are 8 MA291s
for the ALU. The really stupid bit of design, and the boatie who came up
with this needs a touch of the clue-by-four is that the microcode store
is _DRAM_. Yes, you read that right. 4116s IIRC. The problem is, of
course that the execution of the micorocde doens't access all locations
in the store quickly enough, so the RAM is not autometically refreshed.
You guessed it, the CPU is paused every so often asd the control store
is refreshed. That's one thing that slows it right down. Why they didn't use
SRAM is beyond me....
Still, the 11/730 is small enogh to accomodote (10.5" box, and not that
heavy) and repariable. It's my favourite of all the VASen
-tony