> Hm, now I'm not sure *what* I've got.

that's because i mangled my description.

> My VAX-on-wheels cabinets have four drive bays, but inserting a drive
> into one involves moving it front-to-back.  Inserting a Qbus card means
> moving it right-to-left, as viewed from the front of the machine.

that's a ba123.

> I'm Confused. :-/

i screwed up.

> I have two of them.  The one I can easily check on has a sticker
> showing "Model: DH-630Q4-E2".

"Q4" means BA123 in this context.