HP StoreEver DAT Tape Drives - Manual (Page 65)

Setting the SCSI ID on HP StorageWorks DAT drives
See the relevant chapter of this User Guide for more details. Note that host adapters check SCSI IDs only
at power-on, so any changes will not take effect until the host system is power-cycled.
• On internal HP StorageWorks drives, set the SCSI ID by attaching or removing jumpers at the
rear of the drive, see “ Check the drive's SCSI ID ” on page 19.
• On external HP StorageWorks drives, the ID is displayed on the rear panel and can be set
by pressing the little buttons above and below the number (using a ball point pen), see
“ Check the drive's SCSI ID ” on page 19.
• On removable HP StorageWorks drives, the ID is set on the back of the tape array, see
“ Set the drive's SCSI ID ” on page 35.
SCSI termination
Terminators are essential, as they provide the correct voltages on the SCSI bus and prevent unwanted
signal reflections from interfering with data transfers. The rule is:
• There must be termination at both physical ends of the bus and only at the ends.
There are two main types of termination, active and passive. Active terminators reduce interference
and allow faster data throughput. On devices with high transfer speeds, such as HP StorageWorks
DAT devices, active termination is required, using an LVD or multimode active terminator. (Multimode
terminators allow both LVD and single-ended devices to be connected to the same bus. They detect
the type of bus and automatically supply the correct termination. The terminator supplied with HP
StorageWorks DAT tape drives is LVD. Multimode terminators may be used instead.)
Normally the HBA forms one end of the SCSI bus and provides termination. You only need to ensure that
the other end of the bus is terminated.
Internal drives
A suitably terminated LVD internal ribbon cable is supplied with the tape drive. The terminator is usually a
small, rectangular block of plastic attached to the cable end and marked ‘SCSI Terminator’.
DAT SCSI Tape Drives 65