No. It's only the RQDX1 that has the "must
be last on the bus"
problem, and only then if what's below it uses DMA and interrupts.
RQDX2 and RQDX3 have no such limitation. You won't find an RQDX1 in a
MicroVAX II because it is not compatible with the MicroVAX II
processor.
I know of the incompatibility but I'm surprised at the RQDX3 not having
the limitation - every single microPDP and qbus uVAX I used, installed or
watched Failed Circus maintain had to have the disk controller last on the
bus; the only exception to this was if you had the RQDXE extender for
external drives. Even the machines I've got here now are built like that.
of any offhand that won't work in a Q22-CD slot
but that doesn't mean
there aren't any). The MicroVAX II Micronotes actually show such a
configuration, with a processor, single memory card, a DEQNA, an RQDX2,
and a DHV11 (with the DHV11 last, as usual).
The only definition I've seen is that Q22/CD boards are the 'S-handle'
types for the BA4xx (and some BA2xx) and non-CD boards need to either have
jumpers removed (KDA50 springs to mind) or etches cut.
cheers,
--
adrian/witchy
Binary Dinosaurs creator/curator
www.binarydinosaurs.co.uk - the UKs biggest home computer collection?