Quantum DAT 160 Betriebsanweisung

Appendix B  SCSI Configuration Guide

SCSI Cables

Quantum DAT 160 User’s Guide

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For Quantum DAT removable tape drives, termination is provided by 

connecting a terminator to the spare SCSI connector on the rear of the 

tape array. There are two connectors for each bay in the tape array. It 

doesn't 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 each bay in use, you must attach a terminator to the spare 
connector for each device.
If you are using the removable drives to mirror 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.

SCSI Cables

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Cables matter in SCSI systems. There are two factors to consider: cable 

length and cable quality.

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• For single-ended SCSI with Fast devices there is a maximum 

permissible length of 6 meters for a single SCSI bus.

• For single-ended SCSI with Ultra devices the maximum permissible 

length is 3 meters for four or fewer devices, and 1.5 meters for more 

than four devices. 

• For LVD SCSI the maximum length for a single device is 25 meters. 

For multiple devices, the maximum combined internal/external 

length is 12 meters.

• If you have a combination of LVD and SE devices on the bus, the 

maximum cable length reverts to the SE specification. See note on SE 

and LVD interfaces for more information. 

• For best performance, keep lengths to a minimum, but avoid very 

short overall lengths (less than 0.5 meters).