Apple Workgroup Server 9150/120 - Manual (Page 50)

Setting the SCSI ID number
As discussed previously, the Workgroup Server 9150 contains two SCSI
buses: an internal bus and an external bus. The devices on each bus must be
assigned unique ID numbers between 0 and 6. That is, each device on the
internal bus must be assigned a unique ID number between 0 and 6, and
likewise for the external bus. This section tells you how to set the ID number
for an Apple SCSI device. When setting a SCSI ID for another manufacturer’s
device, refer to the instructions included with that device.
IMPORTANT The new SCSI Manager (version 4.3 or later)—an extension to the
Macintosh system software—enables your server to recognize up to 14 SCSI
devices; previously, Macintosh computers were able to recognize only seven
devices. Older SCSI-related applications and utilities may not be able to
recognize more than seven devices, even with the new SCSI Manager. If an
internal device and an external device both have the same ID number, such
software would find only the internal device. If this problem occurs, contact
the distributor of the software.
If you have an Apple SCSI device, set the SCSI ID number as follows:
1 Make sure the device is switched off.
2 Choose a number that doesn’t duplicate the ID of any other SCSI device connected to
your server.
The startup disk’s ID number is preset to 0, the CD-ROM drive’s ID is preset
to 3, and if your server has a DAT drive, its ID is preset to 2. (Your server
itself has the ID number 7.)
The following figure shows the preset ID numbers for these built-in devices.
Internal
SCSI
bus
Startup
disk
0 2 3 4 5 1 6
SCSI ID numbers
(Optional)
DAT drive
CD-ROM
drive
34 Chapter 3 / Expanding Your Server and Connecting Other Equipment