HP StorageWorks Ultrium Full-Height SCSI Tape Drives User Guide (EH853-90905, August 2007)

Setting the SCSI

ID on HP StorageWorks Ultrium drives

Note that host a

dapters 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 SCSI ID.

• 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 removable

HP StorageWorks drives, the ID is set on the back of the tape array, see Set

the drive's SCSI ID.

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:

NOTE:

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

Ultrium devices, active termination is required, using an LVD or multimode active terminator. (Multimode

terminators allow both LVD an d single-ended devices to be c onnected to the same bus. They detect the

type of bus a nd automatically supply the correct termination.)

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.

Removable dri ves

For HP StorageWorks Ultrium removable tape drives, termination is provided by connecting a terminator

to the spare SCSI connector on the rear of the tape array. There are t wo connectors for each bay in the

tape array. It does not matter which is used for SCSI-IN and SCSI-OUT.

If you have each removable drive in the tape array attached to a separate bus, then, for ea ch bay in use,

you must attach a terminator to the spare connector for each device.

If you are using the removable drives to mirro r backups, you can daisy-chain devices (but no more

than two on each SCSI bus) . Connect an LVD-rated cable from the spare SCSI connector for the ﬁrst

device to one of the SCSI connectors for the second device and attach the terminator to the spare

SCSI connector for the second device.

Refer to your tape array documentation for detailed instructions.

Internal drives

HP StorageWorks Ultrium internal tape drives do not supply termination. A suitably terminated LV D

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 ma rked ‘SCSI Terminator’.

Ultrium full-height SCSI Tape D rives