Dell Precision Workstation 450 Service Manual page 48

1 power cable
2 power input connector
1 interface connector
2 colored stripe on cable
3 interface cable
Most interface connectors are keyed for correct insertion; that is, a notch or a missing pin on one connector matches a tab or a filled-in hole on the other
connector. Keyed connectors ensure that the pin-1 wire in the cable (indicated by the colored stripe along one edge of the cable) goes to the pin-1 end of the
connector. The pin-1 end of a connector on a board or a card is usually indicated by a silk-screened "1" printed directly on the board or card.
NOTICE: When you connect an interface cable, do not place the colored stripe away from pin 1 of the connector. Reversing the cable prevents the drive
from operating and could damage the controller, the drive, or both.
SCSI Device Installation Guidelines
This section describes how to configure and install SCSI devices in your computer. To install a SCSI device, you can use one or both of the following SCSI
controllers:
The SCSI connector on the system board. To locate the SCSI system board connector, see the system board illustration, see
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Components" ) or the interior service label.
NOTE: The system board SCSI controller supports hard drives only. Do not connect CD or DVD drives, tape drives, DAT drives, and so on.
A SCSI controller card installed in your computer.
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SCSI ID Numbers
Internal SCSI devices must have a unique SCSI ID number from 0 to 15. If you are using the SCSI connector on the system board and a SCSI controller card
installed in your computer, you have two separate SCSI buses operating. Each SCSI bus has a set of SCSI ID numbers from 0 to 15.
When SCSI devices are shipped from the factory, the default SCSI ID numbers are assigned as follows:
System Board Controller
Device
Controller
Boot hard drive
NOTE: There is no requirement that SCSI ID numbers be assigned sequentially or that devices be attached to the cable in order by ID number. If two or
more devices use the same ID, your computer may hang during POST and in SCSI BIOS.
SCSI devices installed by Dell are configured correctly during the manufacturing process. You do not need to set the SCSI ID for these SCSI devices.
ID Device
7 Controller
0 Boot hard drive
CD or DVD drive
tape or DAT drive
"System Board
Controller Card
ID
7
0
5
6