Re: Using lilo to boot off any drive ...

[Richard B. Johnson]

On Fri, 10 Jan 2003, Manish Lachwani wrote:

> Richard,
> 
> Thanks for the response. 
> 
> Even if I can get the map information using the INT
> 0x13h disk interrupt, I would still need some way of
> knowing if sda has indeed failed. 
> 
> What I am thinking of if it is possible to make the
> "boot" option in lilo.conf variable. Or better,
> introduce a serial# option and the serial# can be
> scanned for on startup. Or make use of a lun# option. 
> 
> I was also thinking if BIOS id's for the disks can be
> used here. Are BIOS id's assigned for all drives?
> 
> Thanks
> Manish

It's a big "depends". Some SCSI controllers will assign BIOS
id's for everything found on the bus, starting at 0x80 for
an ID. Others don't. In fact, some will assign a CD/ROM to
0x00 (Drive A) even if it doesn't contain a boot record. When
that assignment occurs, it's space in the boot-order gets
filled in with the next available drive. It's a mess and you
can't count on anything except that 0x80 will be lowest numbered
"fixed-disk" drive found. That's why you should boot from it,
even if the BIOS allows you to boot from others.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.