Date: Mon, 10 Feb 1997 15:36:37 +0100 (MET) From: Erik Manders <erik@il.ft.hse.nl> To: gjennejohn@frt.dec.com Cc: erik@il.ft.hse.nl, questions@freebsd.org Subject: Re: Bootblock (mis)behaviour Message-ID: <199702101436.PAA01772@charm.il.ft.hse.nl> In-Reply-To: <9702101419.AA16556@cssmuc.frt.dec.com> from "garyj@frt.dec.com" at "Feb 10, 97 03:19:07 pm"
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garyj@frt.dec.com is said to have made the following statement:
>
> erik@il.ft.hse.nl writes:
> > Hello,
> > I recently bought a 3Gb SCSI drive to replace the IDE disks that had
> > been in my machine. After I had disklabeled, installed bootblocks, moved
> > the file systems and installed a new kernel, I removed the IDE and
> > booted the new setup. To my amazement the new kernel continued to want
> > wd0a as its root device, even though `root on sd0' had been in the
> > config file.
> >
> > Things even went so far that even though I typed `sd(0,a)/kernel',
> > the machine said it was booting from `wd(0,a)/kernel'. The kernel was
> > still loaded from the SCSI drive. It later said `changing root device
> > to wd0a'. My DOS stuff (on the same disk) was and is working perfectly.
> >
> > After some hair-pulling, I started looking at the boot block source.
> > I have some theories as to why things are going wrong. It seems to me
> > that the variable `maj' gets zeroed between the assignment
> > `maj = devp-devs' in sys.c:openrd() and the `MAKEBOOTDEV()' macro in
> > boot.c:loadprog(). It's probably before the call to loadprog(), since
> > the printf() at early in loadprog() reports maj=0. Changing the `maj' in
> > the MAKEBOOTDEV() macro to `4' solves the problem. So (probably) would
> > an assignment `maj=4' early in loadprog. It's ugly but it works.
> >
> > Has anyone else here had similar problems? For your information, I'm
> > running -current (CTM-current around 3000, IIRC) on a noname pentium
> > board with an NCR PCI SCSI controller. More detailed information
> > available on request.
> >
>
> did you also remove the IDE disk from the BIOS setup ? The bootblocks
> just use what the BIOS tells them. If the BIOS says that there's an
> IDE disk, then the behavior you're seeing would be explained.
>
> ---
> Gary Jennejohn (work) gjennejohn@frt.dec.com
> (home) Gary.Jennejohn@munich.netsurf.de
> (play) gj@freebsd.org
>
I removed the disk from the BIOS setup, disabled the onboard IDE
controllers and removed the drives and cables from the machine. The
problem could only have been lurking in the bootblocks or somewhere
deep in the BIOS. Of course, after it wanted an IDE disk I was forced
to put an IDE disk back in the machine. I've patched the problem
(and removed the IDE stuff) but it is still strange.
Erik Manders erik@il.ft.hse.nl
--
It is by caffeine alone that I set my mind in motion; it is by the cans of
cola that the thoughts acquire speed, hands acquire shaking, the shaking
becomes a warning; it is with caffeine alone that I set my mind in motion.
--from the movie `Dune', edited
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