Scsi Guidelines - HP c8000 Technical Reference Manual

NOTE: These systems have not been qualified with a mixed configuration of UATA/IDE and
SCSI hard drives.
When installing and operating SCSI devices, you must follow these guidelines:
These systems are equipped with a dual channel U320 SCSI controller. The primary channel
can be used to connect up to 4 internal 68 pin SCSI Disk drives. The secondary SCSI channel
can be connected to an external SCSI connector at the rear bulkhead of the system with an
optional cable assembly.
The Ultra 320 SCSI bus in these systems is a Low Voltage Differential (LVD) bus. HP does
not recommend mixing Single Ended SCSI devices with LVD SCSI devices on the same
SCSI bus. Mixing Single Ended devices on the same bus with LVD devices will result in the
bus running in Single Ended mode, which will result in reducing the data transfer rate of the
bus to the slower Single Ended transfer rate of 40Mbytes/second.
If it is necessary to connect Single Ended SCSI devices to the system, it is recommended that
these devices be connected to the secondary external SCSI port.
If it is necessary to connect 50 pin SCSI devices to the system, it is recommended that these
devices be connected to the secondary external SCSI port.
It is not recommended to mix 50 pin SCSI devices with 68 pin SCSI devices on the same
SCSI bus. If it is necessary to mix these devices on the same bus, care must be taken to insure
integrity of the 68 pin bus.
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CAUTION: Do not route data cables near the air intake to the power supply. Cables routed
in this manner may block the airflow and cause the workstation to overheat.
All SCSI controllers require a unique SCSI ID (0-6 or 8-15) for each SCSI device installed.
The controller identifies a SCSI device by its SCSI ID number rather than its location.
Moving a SCSI device from one position to another on the SCSI chain does not affect
communication between the controller and the device. Take care to ensure that all devices on
the SCSI bus are set to unique SCSI ID numbers. When setting SCSI IDs, note that:
7 is reserved for the SCSI controller.
1 through 6 and 8 through 15 are available for all other SCSI devices.
To set the SCSI ID on a drive, see the instructions on top/back of the hard drive for the
correct jumper settings.
The drive probably displays a diagram of the jumper block. This diagram shows you what
blocks to cover with your jumper. For example, if the drive needs to be set to 3, the drive
might show that the 3 ID bits are at the far left of the connector (ID0, ID1, ID2, and ID3),
then using the jumpers provided, cover each block to set the SCSI ID.
Technical Reference Guide

SCSI Guidelines

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