5190/5194 Modular Tape Subsystem Manual

Introduction to the Modular Tape Subsystem

5190/5194 Modular Tape Subsystem Manual—426878-002

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SCSI Extender for Fiber-Optic Cable

For cable lengths from 500 meters to 2 kilometers, contact your service provider. If

you want a third party to install the cable, use the 2-kilometer Cable Specification listed

in Appendix A, Part Numbers.

Back-End Board (6760 Adapter)

The back-end board (BEB) translates fiber-optic signals from the 6760 ServerNet

adapter into SCSI commands and information for the cartridge tape drive. A cage-like

sheet-metal enclosure houses the BEB and plugs into a SCSI port on the back of the

drive CRU. The BEB enclosure is visible only when the hinged door on the rear of the

module (the rear bezel door) is lowered. For an illustration of a BEB, see Figure 3-13

on page 3-25.

One BEB can serve one drive CRU. The BEB contains four light-emitting diodes

(LEDs). Two LEDs are external (easily viewed at the back of the BEB cage) and two

smaller LEDs are mounted internally on the circuit board of the BEB. The internal

LEDs are used by trained service providers. You do not need to use the internal LEDs

to troubleshoot the BEB.

All BEB LEDs are visible if the hinged door on the rear of the module is lowered or

removed. For a description of the BEB LEDs, see Replacing a BEB on page 6-2. For

BEB problem-solving using these LEDs, see Troubleshooting a BEB on page 6-2.

Fiber-Optic Cable (6760 Adapter)

A duplex fiber-optic cable connects the 6760 ServerNet adapter to the BEB at the rear

of the tape drive module. Cable lengths can range from 10 meters (33 feet, the default

length) to 2 kilometers (1.2 miles). Part numbers for fiber-optic cables are listed in

Appendix A, Part Numbers.