Primary channel B?

[Mike Bilow]

Eugene Blanchard wrote in a message to Mike Bilow:

 EB> I am using an AHA2742N EISA card. I have set Channel B in the 
 EB> AHA2742 bios  as the primary channel for boot purposes. Channel 
 EB> B is internal bus only, A is both internal and external.  

 EB> I need to have Channel B scanned before Channel A so that my 
 EB> boot drive appears as /dev/sda. Currently Channel A is scanned 
 EB> first and my boot drive appears as /dev/sdd. Unfortunately, 
 EB> lilo requires the boot drive to be bios C: (/dev/sda) or D: 
 EB> (/dev/sdb).

 EB> Is there a simple fix for this, swap channel number variables 
 EB> (0 and 1) in the source files?

I don't recognize the "N" suffix, but I assume it is the same as "T" suffix?

Anyway, the problem here is really in Lilo.  Until Linux is booted, obviously
Lilo must go through BIOS to get the kernel loaded.  Since most systems
originally had BIOS support for only two hard drives, apparently this got
written into Lilo.  Older Adaptec SCSI controllers, such as the AHA154x, did
require that the boot device be ID 0 or 1 for this reason.

If the controller ROM supports booting from an arbitrary SCSI device, then Lilo
should just make the necessary calls into BIOS and go with that.  Until you
posted your message, I didn't even know that such a limitation existed in Lilo,
and it should be fixed in Lilo rather than in the SCSI subsystem.  Hard drives
supported by BIOS are accessed by zero-based device number with the high-bit
set (0x80, 0x81, and so on) to distinguish them from floppy drives.
 
-- Mike



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