After trying a netbsd-current kernel with WDDEBUG turned on, now I see
the following only when /usr is mounted.  It usually takes a while for
it to appear, when it does; it spells certian death (ie the machine
locks):

wdc0: lost interupt: status 58<rdy,seekdone,drq> error 0
wdc0: lost interupt: status 59<rdy,seekdone,drq,err> error 40<uncorr>
wdc0: lost interupt: status 59<rdy,seekdone,drq,err> error 40<uncorr>
wdc0: lost interupt: status 59<rdy,seekdone,drq,err> error 40<uncorr>
[...]

Ideas?  I'd look at source, but that's a bit hard to do now :-)

I appears it may be inode related in that when I touch certian directories
with ls, this pops up.  I'm thinkin of cutting my losses and backing up
what I can and newfs'ing /usr and starting over.

Anyone seen this before?  Advice?  Prayers? :-)