Dual channel SCSI adapters like the AHA3940 is an example of
   SCSI adapter with two scsi buses.  If this was the only HBA 
   on the mainboard, and the builtin IDE controllers were disabled 
   in the BIOS, then the HBA's would be:

       c0b0t?d?s?
       c0b1t?d?s?

   The b# is the part that changes for multibus adapters.