Scsi Devices; Guidelines For Using Scsi Devices - HP xw4000 Hardware Reference Manual

SCSI Devices

Guidelines for Using SCSI Devices

Hardware Reference Guide
This section contains information relating to SCSI device guidelines
and installation.
When installing and operating SCSI devices, you must follow these
guidelines:
■
A single Ultra SCSI controller supports up to seven SCSI devices
per channel.
■
Each Wide-Ultra SCSI, Ultra-Wide SCSI, Wide Ultra2 SCSI,
Ultra 320 SCSI, or Ultra 160 SCSI controller supports up to
15 SCSI devices per channel.
■
If using multiple SCSI devices, HP recommends that the devices
be split between Channel A and Channel B, if available, for
optimum performance.
■
SCSI cable recommendation:
53 inches maximum length twisted-pair, LVD cable with built-in
terminator, maximum of five drives with a minimum driving
spacing of 5.25 inches.
■
The SCSI controller requires a unique SCSI ID (0–7 or 8–15) for
each SCSI device installed. The controller identifies a SCSI
device by its SCSI ID number rather than by 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. The reserved and available SCSI ID numbers for SCSI
devices are:
❏
0—reserved for the primary hard drive
❏
7—reserved for the controller
❏
1 through 6 and 8 through 15—available for all other
SCSI devices
■
Every SCSI chain or circuit must be terminated (closed) at both
ends. Termination can be accomplished through one of the
following methods:
Hard Drive Installation Guidelines
B–3