Re: Bug - SCSI and IDE drives

[Jochen Hoenicke]

On Dec 30, Chris Wedgwood wrote:
> On Fri, Dec 29, 2000 at 12:47:18AM -0600, James Magnusson wrote:
> 
>     I just installed Caldera eDesktop 2.4 on to a dual processor machine at
>     home. And it took two days to figure out why Grub wouldn't boot linux.
>     It would just give me its command prompt. The reason it was doing this
>     was because I had the BIOS set to boot off of SCSI frist. And this was
>     confusing it. For whatever reason once linux starts up it assigns the
>     IDE drive as (hd0) and the SCSI drive as (hd1), but the system was set
>     to boot the SCSI drive first making it (hd0) and the IDE (hd1). 
> 
> lilo also has this problem; it's a bit tricky to solve but I'm
> tempted to claim linux is at fault here; it doesn't detect the drive
> order from the BIOS -- which in theory it could do in the startup
> code before switching to protected mode
> 
> can someone comment as to how other OSs handle this? I'm pretty sure
> FreeBSD gets it right

The OS doesn't care about BIOS disk order.  It just uses it's own
numbering.  Only the boot loaders need to know/guess the BIOS order.

Grub normally numbers the IDE drives first, then the SCSI drives,
since most times this is the ordering.  But you can use the
--device-map flag or the "device" command to change the mapping under
grub shell.  See the documentation for details.

Another possibility is to create a grub floppy and install from
there.

James Magnusson wrote:
>     On windows NT 4.0 Grub wouldn't boot it if it was an NTFS partion.
> but when I reinstalled NT as a FAT partion it worked fine.

Grub doesn't know about NTFS, but since you only want to chainload the
first sector you can ignore the file system with rootnoverify:

rootnoverify (<NT-Part>)
chainloader +1
makeactive

  Jochen