Help please!

[Stephen Hodgman]

Patrick,
Thanks for the explanation.
Yes, you were correct, if I put the specific device into the lilo.conf then it boots 
correctly. Hooray!

Thanks to everyone who responded and who thought about it. I am a little wiser now 
in my understanding of the boot process anyway...

Cheers,

On 21 May 2002 at 10:24, Patrick Cole wrote:

> Mon, May 20, 2002 at 02:04:01PM +1000, Stephen Hodgman wrote:
> 
> 
> > I have a system with an IDE drive with bootable Debian potato on it. (/dev/hda).
> > this disk works fine and I can boot OK.
> > I have a SCSI disk /dev/sda which has Potato on it also.  However when I make the 
> > scsi disk the boot disk I get "LIL-" and nothing.  Doco suggests running lilo to fix it but 
> > I am getting nowhere with that.  This is what I am doing:
> [...]
> > I then reboot, change the scsi disk to be the first boot device and get "LIL-"
> > Now, I had this working last week (Grr...) 
> > What stupid thing have I done please?  thanks.
> 
> This is because when you run lilo it discovers the bios geometry for the
> given disks in boot= and root= and stores that in the bootsector to get
> to where it needs to go. When you have your system with hda as the first
> hard drive, this will map to bios disk 0x80, and your scsi disk will be
> somewhere after that (0x81 if you have no more disks after hda apart
> from your scsi drive).  It also depends on which sequence your
> controller bioses initialise - more often than not though, on board
> controllers initialise and assign bios disk numbers first unless your
> motherboard bios has the option to init the scsi adapter first. The problem 
> stems from the fact that when you're running lilo your first disk (hda) is 
> 0x80, and your scsi disk is something else, but when you tell the scsi bios 
> to init first, the scsi disk becomes 0x80, and lilo gets very confused as
> it's looking for a root partition on disk 0x81 which is now your IDE
> disk, but you want it to be your scsi disk. 
> 
> So what you have to do is force lilo to use a specific bios disk number, 
> like such:
> 
> disk=/dev/sda
> 	bios=0x80
> disk=/dev/hda
> 	bios=0x81
> 
> And then lilo should be a happy camper when you swap the sda over to
> 0x80 to boot it.
> 
> Of course naturally 0x81 might not be the right one if you have more
> than the two disks, but you get the picture.
> 
> -- 
> Patrick Cole <Patrick.Cole at anu.edu.au>
> Programmer, the John Curtin School of Medical Research, ANU 
> PGP 1024R/60D74C7D C8E0BC7969BE7899AA0FEB16F84BFE5A   
> 

---

Stephen Hodgman               steve at namsys.com.au
Namadgi Systems                Ph. +61 2 6285 3460
Canberra                       Fax +61 2 6285 3459
Australia