scsi pci vs FC2?

[Jack Howarth]

   One other note about this problem of aic7xxx not automatically
loading. One of the Adaptec cards (the 2910) outputs some
feedback under the BIOS while the machine comes up. This output
includes the Adaptec firmware information and the scsi devices
the card finds. On the other box I have the attached drives
always appear but on the new box with the Tyan Tiger motherboard
I always find that while the Adapatec firmware information
is shown no drives are listed. Does this suggest that the BIOS
is somehow blocking the attached scsi drives from being probed?
Thanks in advance for any suggestions.
                      Jack
ps it still is confusing none the less why the occurance of

alias scsi_hostadapter1 aic7xxx

...in /etc/modprobe.conf doesn't force the driver to be loaded
anyway. As I said before, I find manually modprobe it after 
booting the aic7xxx driver loads and the drives appear in
/proc/scsi/scsi on the scsi1 bus.