tlug: Booting from SCSI and IDE drives

[Dennis McMurchy <denismcm@example.com>]

  Hi,

  Some of you with SCSI disks may find this tip useful.  I was
booting my main Lignux installation from a floppy for almost a year
because even with SCSI selected as the bootdisk in the BIOS setup (of
this ASUS P2B motherboard), 'lilo' didn't seem to be able write
anything bootable to the MBR on the SCSI disk.  It wouldn't interfere
with an existing IDE hard drive MBR, but would just fill the screen
with zeroes when I tried to boot it.  Hey, and I kind of like the idea
of booting a state-of-the-art system from a legacy floppy anyway, so I
didn't pursue the issue.   

  This spring I was building a similar machine in my cabin back in 
Canada (ASUS P2BDual/U2WSCSI motherboard), and didn't bother attaching
any IDE devices at first.  So I discovered by chance that as long as
no hard disk is on the IDE bus (it's not enough just to disable IDE in
the BIOS - you have to actually disconnect the device from the
motherboard), then 'lilo' does a perfectly fine job of making the SCSI
disk bootable.  When you then (re)attach an IDE hard drive, it will
work as expected  and you can boot from either the SCSI or IDE drive by
selecting the bootdisk in the BIOS setup.  

  Somehow I suspect this is probably not a limitation only of the
ASUS motherboards I'm using, so I thought some of you might find the
info useful.  Of course, if someone can tell us what's _really_
happening here, that would be great too.

  Cheers,  Dennis
  

  

Dennis McMurchy, 
Sointula, B.C. / Tojinmachi, Fukuoka
Canada           Japan


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