tape drive

I have an HP C1537a scsi tape drive on an adaptec 2940 U2W. Red Hat 6.1

detected the controller no problem, and the tape device.  Only problem is I
dont know where the tape device is.  I tried to mount /dev/st0 and
/dev/nrst0 and it always says they are not vlock devices.  I am trying to
use BRU and I need to know the device.    Anyone have experience with this??
Thanks.

- Joel