Apollos tend to be really thin on the ground (manuals and Domain OS
media even more so).
--
I'd still like to scan the material that Bob Shannon has, since, as
you've noticed, DOMAIN docs were tossed when the machines were.
Apollo hardware docs are unobtainium.
I tried contacting the one person who was working on porting NetBSD
to DN3xxx/4xxx, because he had done a LOT of reverse engr and boot
prom disassembly for the machines, but got nowhere. It sounded like
he lost interest in the whole thing, and didn't bother to save what
he had done.