Looking back through the archives, I noticed a few pr's by John Kohl
describing and suggesting fixes for various unionfs problems,
including kern/792 & kern/892. 

Have these been fixed? I suspect a lot of my recent wedges have been
due to me mounting stuff like:
	fdesc		/dev		fdesc	rw,union	0 0
	/dev/sd0f	/z/0		ufs	rw		1 2
	/z/0/src	/usr/src	null	rw		0 0
	/var/obj	/usr/src	union	rw		0 0
Mount shows:
	fdesc on /dev type fdesc (local, union)
	/dev/sd0f on /z/0 type ufs (local)
	/z/0/src on /usr/src type null (local)
	<above>:/var/obj on /usr/src type union (local)

If there are any known problems will nullfs mixed with union I'll give
the nullfs the flick and union mount /var/obj over /z/0/src. That is,
of course, if union is relatively stable.

This is with a kernel with sources from 950517.

PS: since mycroft's changes to dev/isa/com.c of 950513, 'break' on the
comconsole works! Before then I could use ddb from the comconsole, but
it would flat out ignore my ~# from tip... This is an excellent fix :)

-- 
Luke Mewburn, <lukem@telstra.com.au>
`Think of it as Evolution in Action.' - "Oath of Fealty", Niven & Pournelle