This pair needs 68W and the
manual suggests a H3490 expansion bay, but is this for the additional
power or just the slot capacity or both?
The KDA50 is (in)famous for its high power requirements; I imagine that's the main
reason for the recommendation.
I'm a little surprised/impressed to see that DEC SDI can run to
50-foot cables between host and device.
As someone who has barely tinkered with DEC SCSI and never used MSCP
(does TK70 count?) DEC SDI seems quite exotic.
TK70 is a tape drive, it's controller speaks TMSCP.
I've never used a DEC MSCP controller, but second party SCSI controllers are
reasonably common. Emulex, CMD, and others made MSCP scsi controllers.