freebsd 4.8-STABLE hangs on boot with no error message

[Matthew Seaman]

On Fri, Nov 28, 2003 at 09:28:23AM +0000, Neil Brown wrote:

> I'm running freebsd 4.8-STABLE, I installed it a
> little while ago and it has been running fine as my
> broadband router for a few weeks now, no problems.
> 
> This morning there was a powercut, and when I came to
> the machine and attached a monitor, I discovered that
> it was making it through the BIOS, getting to the
> spinning -\|/-\|/ prompt, where it freezes on the
> first | every time.

Uh-oh.  That's bad.  That shows the system is trying and failing to
read the kernel from your hard drive.  
 
> If I press enter quick enough at the right moment I
> can get the boot prompt, but then the | appears and it
> freezes.  I can still turn numlock on and off (a sign
> I've gone by for years that the PC hasn't totally
> locked...) and ctrl-alt-del still reboots but it's
> clear that the machine is not going anywhere further.
> 
> I can chuck a CD drive in and boot from the freebsd
> install disk or knoppix or whatever will help me, does
> anyone have any idea as to how I can fix it or what
> log file I should examine etc?

Can you boot to single user mode from Disk2 of the 4 CD set?
(Alternately, you can use the install and fixit floppy images from
ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/4.8-RELEASE/floppies/)

If so, first thing to try is running fsck on your root partition:

    # fsck -y /dev/ad0s1a

(Assuming you're using IDE disks and you've got FreeBSD installed into
the first slice -- adjust as necessary)

If you can fsck the filesystem, then try mounting it:

    # mount -t ufs -o rw /dev/ad0s1a /mnt

If you can get this far, then you're in fairly good shape and can
probably recover the system without doing a full restore-from-backup.
If not, then it seems that you've had a really bad disk crash: at best
you'll be able to reinstall and things will work well enough.  At
worst, the disk is completely toast.

If you can access the drive, then check that you've got a kernel image
available on the drive (/kernel would be good, or /kernel.old or
/kernel.GENERIC).  If necessary try copying the kernel image from the
CD.  Once you've got that far, try booting again from your hard drive.
Once you've got the system booting up again, then going through a full
buildworld cycle would be a good idea.


	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
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