best way to determine disk connection type



Hello,

with in linux (kernel 2.6.15) SCSI/SATA/FCAL disks all look like scsi disks.
What's the best to determine the type of disk ?

Is the scsi_level (/sys/class/scsi_devices/x:x:x:x/device) an appropriate way ? For a SATA disk it shows 6 but i don't know what it does for a FCAL disk.

Thanks in advance,
Tobias
.