24 Nov
2015
24 Nov
'15
7:55 a.m.
3. The Q-bus comes in 2 (or 3?) flavors, the original
with 18 bit addresses,$
I wouldn't go that far. I would say the MicroVAX-II counts as "in the
Qbus world", and it has hardware to map Qbus memory space accesses to
memory accesses, rather like the Unibus Map you sketch. DMA is "always
to the memory address specified" only if you never look past the Qbus
view of the world; from the CPU's point of view, Qbus DMA addresses get
remapped before hitting memory.
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