[9fans] PCNet and other short stories

[Lucio De Re <lucio@proxima.alt.za>]

There will be working copies of etherpcnet.c on my web site in the
next hour or so:

	/sys/src/9/pc/etherpcnet.c
	http://wow.proxima.alt.za/src/kern.pcnet.c
and
	/sys/src/boot/pc/etherpcnet.c
	http://wow.proxima.alt.za/src/boot.pcnet.c

intended (and tested) to operate with the old Am79c960 but designed
for the entire range of controllers.  The list is in the file headers
and I'm also hoping to merge the two sources (despite Bell Labs's
aversion for #ifdefs) as they seem similar enough to warrant it.

As mentioned I've only tested these on the original controller chip,
I'll perform further tests on a VMware host (that will take some
putting together, unfortunately) and leave it to interested parties to
do additional testing - right now the untested portions are in a
potentially disastrous state.  At this point, if anyone wants to send
me some hardware to test against, I'll gladly return it when done
(that's probably more expensive that buying the stuff new - e-mail me
for details).

I was astounded at how well 9P handles broken device drivers (I ought
to have guessed so, but I didn't think about it).  Being a bit of an
embedded fan, I was very worried about damaging information on the
fileservers (et al.) on the network, but nothing of the sort ever took
place, thank goodness.

Lastly, the unsolved problem of the boot hang on slow hosts.  To all
who encountered the problem, I have one piece of advice: check your
floppy disks and drives.  All problems I had with such hangs have been
solved by making sure the diskettes were readable on the target host.

It's a bit of a chicken-and-egg situation, caused, I am almost
certain, by a rather unforgiving and uncommunicative floppy disk
driver, but it's worth keeping in mind.

++L