>From: Greg Earle <earle@isolar.Tujunga.CA.US>
>
>However, one time I saw some kernel messages before this happened; something
>about a disk error while reading ("fd0a: hard error reading fsbn NN [...]"
>or somesuch), and then a "panic: can't mount root" appeared, before the
>emulator went off into never-never land again.

For what it's worth, I have seen this type of message on a "real" PC
(DEC PC/XL 590).  After managing to get the base system installed anyway
(with lots of complaints whenever reading a floppy) I then reinstalled
everything over the network (not trusting the stuff I had loaded from
the "bad" floppy.)

After getting the system up, I compiled a very pared-down custom
kernel, containing no probes for devices I didn't have.  (I also
upgraded to -current at the same time, so there's definitely more than
one variable in this equation.)  I haven't seen a floppy error since
doing so.

I suspect that some combination of probes in the generic kernel is
enough to seriously confuse the floppy device.

I could probably be convinced to investigate this some more and try to
find exactly what causes the problem, if anyone really cares.

--
entropy -- it's not just a good idea, it's the second law.