Subject: Re: Time to panic... :-)
To: Scott Almburg <firstname.lastname@example.org>
From: Bertram Barth <email@example.com>
Date: 04/16/1996 00:57:00
> b/3 mua0 works from the tk50 boot tape.
> edlabel works ok for the RD53 disk
> used 20000 for part a, 20000 for part b, 138672 for part c, and
> 98672 for part e
> copy works ok (takes a long while, about an hour)
Did the tape sound "normal" during the copy operation or could you
hear it getting stuck sometimes and moving back to read the same block
again and again?
> when I try and boot the miniroot from disk
> : ra(0,0,1)gennetbsd
> I get the normal booting messages and then the
> Root Device?
> prompt. I enter ra0* , then I get a panic: trap adr 0
> and the system goes into debug?
> What's causing the panic trap, and is there anything I can run in db> mode
> to investigate the problem?
I've seen things like that happen when there are bad blocks on the
boot media. Standalone drivers are not at all verbose, thus you usually
don't realize if a block could not be read into memory. When writing
to disk, the complete memory-area where miniroot was read into gets
dumped onto the root-device, including the "holes" or "blind spots"
which are usually filled with zeroes or garbage. Depending on where
the bad blocks were located, these "holes" might now be part of the
kernel binary on your root-disk and if you try to load/execute the kernel,
then accessing such a "hole" results in a panic with trap addr 0...
Try copying from a different tape. If that new kernel crashes at the
same spot, then it's likely to be a problem with the kernel/your machine.
If that new kernel crashes at a different spot, then it is/was caused
by bad blocks on your tape.