error 1 lba 752976 while booting from USB key to install

[John Baldwin]

On Thursday 10 July 2008 10:52:31 am Mel wrote:
> On Thursday 10 July 2008 14:46:58 Matthias Apitz wrote:
> > Hello,
> >
> > I've some server (a 2 years old HP NAT 1000s storage system) and
> > I want to drop the installed W2k system and re-install it with
> > FreeBSD 7.0R and later use it as a central backup-system with
> > Bacula.
> >
> > The problem is that this server has no CD or DVD device, but can
> > (theoretically) boot from external USB CD/DVD (which I don't have
> > either);
> >
> > so I cam up with the idea to boot from that USB key I have used to
> > install 7.0-REL on that eeePC, i.e. the USB key works fine in any
> > laptop; on the HP NAT 1000s storage system it says:
> >
> > FreBSD/i386
> > Default: 0:ad(0,a)/boot/kernel/kernel
> > boot: error 1 lba 752976
> > No /boot/kernel/kernel
> 
> Let me ask a stupid question: why is it trying to access an ATA/ATAPI disk, 
> not an USB (scsi da(4)) disk. Can you boot via:
> 0:da(0,a)/boot/kernel/kernel
> 
> Or variants of those, see boot(8) for the syntax explanation.

That stuff is all obsolete.  For the boot code, all the disks look the same, 
they are BIOS devices 0x80, 0x81, etc.  We just use 0x80 + unit for 'ad' 
and 'da' and 0 + unit for 'fd'.  Before /boot/loader, the 'ad' vs 'da' used 
to matter as we used that to figure out which driver (and thus which cdev 
major) to use for / and passed that to the kernel.  However, /boot/loader now 
reads /etc/fstab from / and passes the source of '/' from that as a string to 
the kernel, so none of the cdev major stuff is needed anymore (and it doesn't 
work either).  The loader handles this better where disks are all 
called 'disk0', 'disk1', etc.

-- 
John Baldwin