External Scsi Expansion - Compaq AlphaServer DS20E Reference Manual

External SCSI Expansion

External SCSI devices, such as tabletop or rackmounted storage devices, can
be connected to the system using PCI-based SCSI adapters. Use the following
rules to determine if a particular device can be used:
The device must be supported by the operating system. Consult the
software product description for the device or contact the hardware
vendor.
A maximum of seven devices can be attached on any one SCSI
controller.
Each device on the bus must have a unique SCSI ID. You may need to
change a device's default SCSI ID in order to make it unique. For
information about setting a device's ID, refer to the guide for that
device.
The entire SCSI bus length, from terminator to terminator, must not
exceed 6 meters for fast-differential connection to SCSI, or 3 meters for
fast single-ended connection.
Ensure that the SCSI bus is properly terminated and that no devices in
the middle of the bus are terminated.
For best performance, wide devices should be operated in wide SCSI
mode.
Compaq Confidential – Need to Know Required
Writer: Robert Young Project: Compaq AlphaServer DS20E System Comments:
Part Number: ER-K8F6W-UA .A01 File Name: h-ch7 Using the Storage Subsystem.doc Last Saved On: 10/4/99 11:13 AM
Using the Storage Subsystem 7-23