Connecting External Options

Setting SCSI IDs for External Devices

You must set a unique SCSI ID for each SCSI device that is connected to a SCSI-2 controller, so that the SCSI-2 controller can identify the devices and ensure that different devices do not attempt to transfer data at the same time. Therefore, do not set the SCSI IDs for external devices to the values that you use for internal devices. Refer to the instructions that come with the SCSI devices for more information about setting a SCSI ID.

Notes:

1.If you install a SCSI-2 adapter, you can use the same SCSI IDs that you use for the integrated SCSI-2 controllers.

2.The two integrated SCSI-2 controllers on the system board operate independently. Each controller can support a maximum of 14, 8-bit or 16-bit SCSI devices. The 16-bit devices support SCSI IDs 0 to 15, and the 8-bit devices support SCSI IDs 0 to 7.

Your server automatically sets SCSI IDs for hot-swap drives. These IDs are set according to the jumper settings on the hot-swap backplanes. The SCSI ID for the preinstalled CD-ROM drive is set to 5, the SCSI ID for the backplane is set to 6, and the SCSI ID for the SCSI-2 controller is set to 7. The processing sequence for SCSI devices is set according to their IDs.

Chapter 4. Installing Options 209

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IBM 704 manual Setting Scsi IDs for External Devices