User`s guide

DigiDrive Guide 16
18 If your system came with the dual-channel
board, repeat steps 1 through 17 to attach the
second stack of drives to the system.
Determining SCSI IDs
You must consider the type of system the drives
are attached to when determining the SCSI ID
for the drive. Macintosh systems have an inter-
nal SCSI bus, an external SCSI bus, and a PCI-
based SCSI board. Windows systems may have
support for SCSI integrated into the mother-
board (e.g. IBM Intellistation) or provided by
one or more PCI-based expansion cards.
Digidesign recommends that you set the SCSI
IDs for the devices on each SCSI bus in sequen-
tial order, that is, starting with the device at-
tached closest to the Digidesign system as ID 0
(see Figure 16).
SCSI IDs on Macintosh Systems
For each SCSI hard drive you connect to the
Macintosh operating system, you must assign a
SCSI ID so the system can find and access the
drive. When you are setting the SCSI IDs, re-
member the following:
◆ The Macintosh system might have several
SCSI buses: a built-in internal SCSI bus, a built-
in external SCSI bus (on PCI-based systems), and
one or more Digidesign SCSI buses that are
added using SCSI accelerator boards. The dual-
channel SCSI accelerator board adds two SCSI
buses to the Digidesign system.
◆
You can attach six additional narrow SCSI de-
vices to the external built-in SCSI bus on the
Digidesign systems. This SCSI bus has its own
set of unique SCSI IDs from 0 through 6.
Figure 15. Ultra, Narrow SCSI Terminator Connection
Do not set the SCSI ID for any drive on any
SCSI bus to SCSI ID 7. This SCSI ID is re-
served for the SCSI accelerator board to
which the drive is attached. Setting a drive
to the same SCSI ID as the SCSI accelerator
board can prevent the drive from mounting
on the desktop, or prevent your Digidesign
system from booting correctly.
0
+
Narrow
50
-
pin SCSI connector
Ultra, narrow SCSI terminator
Drive
Figure 16. Setting SCSI IDs
Connect all 68-pin, wide SCSI devices on a
SCSI bus before connecting the 50-pin, nar-
row SCSI devices. All narrow drives must
use SCSI IDs less than 7.
ID 7
SCSI accelerator
Digidesign system
SCSI drives
Terminator
SCSI cables
ID 0
ID 1
ID 2
ID 3
board