The gist of the solution is that I reset my Mac to B&W w/ the monitors
control panel.  Rebooted my Mac. And then booted into NetBSD.

I think I kind of sort figured it out, but it's too weird for me to be
comfortable. Looking through the posts on 

http://routbort.neuro.duke.edu/netbsd/ I finally dug out this
reference to colors.

http://routbort.neuro.duke.edu/netbsd/digests/v01.n1240

>On Tue, 19 Sep 2000, Jesse Reynolds wrote:
>
>>  Well, it's working now. 1.5a won't do any more than 256 colours on my
>>  Quadra for some reason. And, it is important to reboot the mac after
>>  changing the number of colours and before booting bsd... very
>>  confusing!!!
>>
>>  for example, if the machine boots up with millions of colours, I
>>  change the number of colours to 256, then bsd will panic. I have to
>>  reboot the mac after changing the colours.
>

Of course I still some problems:

1. I had previously set my mac to black & white, and have no idea how
it got changed. This can make rebooting headless tricky. Since I want
to just leave it on I should be ok for the most part. But if it resets
the monitor when it restarts headless I will get confused again.

2. Even with memory problems, it is surely a sign of some sort of a
bug that the memory can conflict between monitor and ehternet, that
way. Programs should fail more gracefully than that.

Oh well! I'm just going to pull the monitor and hope it works for a
while.

-- 
Josh Kuperman                       
josh@saratoga.lib.ny.us