I've got a VAX4000/200 with a CMD CQD223 in it. Works great for disks. 
However, when I hook up a CD-ROM, it recoginizes it as a tape, and shows 
MUA0, and device mt0 as a TU81. Will I be able to read CDs off this 
thing, or is there some bit of config in the controller I need to 
change? What can I do to get it recognized as cd0, or will it work fine 
as mt0?

Perhaps I should test. Hang on...

Nope, just get mt0: Input/Output error. Any ideas?