I have the programming and registers manual for this and a few 
other AViiON machines at my house; and an AViiON 410. 

This might be of interest:
http://www-csc.dg.com/csc/custdocs/40020761.pdf <- the manual I have
http://www-csc.dg.com/csc/custdocs/40021631.pdf

http://tofu.alt.net/~lk/291.paper/291.paper.html <- porting BSD

-- 
I'm trying to port NetBSD to my cup of tea, but it keeps kernel panicking 
on refill. This is odd, because I ported it to my toaster and my bookcase 
easily enough and it survives bread- and book-replacement fine.

Any hints?

Jared Earle - http://mail-index.netbsd.org/tech-ports/2002/07/04/0000.html