the 'a'/'b/'c' etc refers to the device, and '1'/'2'/'3' etc' refers to the partition, i.e.
sda1 = scsi type device (sd), first (a) drive, first partition (1)
sdb6 = scsi type device (sd), second (b) drive, sixth partition (6)

what error messages are you getting? can youp ost the results of 'cdrecord -scanbus' and 'rescan-scsi-bus.sh'?