A SCSI Target Identification for the Sun SCSI Expansion Pedestal Installed Devices

A.1 Introduction

This appendix describes the SCSI target identification and locations for the SCSI devices in the Sun SCSI Expansion Pedestal as configured at the factory.

This appendix discusses the maximum configuration, as supported by Sun, but the same rules will apply for all available products installed in the Sun SCSI Expansion Pedestal by location.

Appendix B discusses the Sun SCSI Target platform and illustrates the correct procedure for setting the SCSI Target ID and installing the Device Target ID jumpers on Sun supported SCSI devices.

When installing or replacing a SCSI device in the Sun SCSI Expansion Pedestal refer to this appendix for the correct location and Target ID, and Appendix B to set the jumpers correctly on the device.

A.2 System Configuration

The Sun SCSI Expansion Pedestal may contain three drive trays, depending upon the model.

The top tray may contain one or two tape drives, or a tape drive and a SunCD and the two other trays (if installed) always contain hard disks.

The Device Target ID serves two purposes:

1. To uniquely distinguish each device on the same SCSI bus

2. During system power-up the devices are spun up in a predetermined delayed order. This order is related to the target ID of the device.
The purpose of this is to reduce the peak currents that would be drawn if all the devices attempted to spin up at the same time when power is applied.

A.3 SCSI Target ID by Location

Top Tray SCSI Target ID Configurations

There are two available device configurations for the top tray.

Figure A-1 Tape Drive and SunCD in the top tray

Figure A-2 Two Tape drives in the Top Tray

Bottom and Middle Trays SCSI Target ID Configurations

Figure A-3 Four Hard Drives in the Middle or Bottom Tray

A.4 SCSI Device Address

The following table shows SCSI device address as determined by SCSI target ID on more than one SCSI bus.

Table A-1 SCSI Expansion Pedestal Drive Configuration