Scsi Guidelines - HP xw9300 Service And Technical Reference Manual

SCSI Guidelines

When installing and operating SCSI devices, you must follow these guidelines:
• A wide (68-pin) SCSI controller with two channels, one for internal devices and one for external
devices. Five internal SCSI devices are supported.
• If multiple SCSI devices are used, split the devices between Channels A and B for optimum
performance. Cable length for the second channel should not be longer than 18 inches.
CAUTION: Do not route data cables near the air intake to the power supply. Cables routed in this
manner can block the airflow and cause the workstation to overheat.
• All SCSI controllers require a unique SCSI ID (0–15) for each SCSI device installed. Refer to the
"Jumpers" section on page 175
Every SCSI chain or circuit must be terminated (closed) at both ends. Some system boards have both
•
ends of the SCSI cable connected to, and terminated by, the system board. Termination can be
accomplished in one of several ways:
• Use a cable with a built-in terminator.
• Use a cable with a terminating resistor plug in the last connector.
• Connect a SCSI device with its termination enabled into the last connector.
• Connect an external SCSI device with its termination enabled to the external SCSI connector on the
rear panel of the workstation.
• Turn on all external SCSI devices before turning on the power to the workstation. This enables the SCSI
controller to recognize the external devices.
172 SCSI Devices
for more information.