C-2
Things You Should Know
Writer: Pamela King Project: SMART-2DH Array Controller Reference Guide Comments: 295469-002
File Name: J-APPC.DOC Last Saved On: 2/27/98 12:03 PM
COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED
SCSI Termination
All SCSI buses require termination on both ends of the bus to prevent signal
degradation. The SMART-2DH Controller supplies the termination on the
origination end of the SCSI bus. All internal SCSI cabling recommended for
Compaq servers provides the necessary termination for the opposite end of the
bus. Therefore, individual SCSI drives in Compaq servers should not contain
bus termination.
External SCSI devices must also provide termination for the SCSI bus. This is
supplied in Compaq external storage systems such as the ProLiant Storage
System or SCSI Storage Expander. Therefore, individual SCSI drives in
Compaq storage systems should not contain bus termination.
SCSI IDs
The SMART-2DH Controller contains two SCSI buses (ports), each of which
supports up to seven drives. The internal and external connectors reside on
separate SCSI buses; peripherals attached to either connector must have a unique
SCSI ID in the range of 0 to 6. SCSI IDs on all peripherals are set manually with
switches or jumpers on the device itself, or set automatically on Compaq
products that support hot-pluggable drives. The SCSI ID determines the device’s
priority when attempting to use the SCSI bus. The highest priority, SCSI ID 7, is
reserved for use by the controller. SCSI IDs 8 to 15 are not currently supported
by the SMART-2DH Controller.
SCSI Cabling
The cables available from Compaq that connect your SMART-2DH Controller
option board to SCSI drives in any Compaq server or external SCSI product
can be found:
■
in the SMART-2DH Array Controller Installation Guide, or
■
at
www.compaq.com/products/servers/servername/scsicableguide.html, or
■
in the Setup and Installation Guide, or Reference Guide, that
accompanied your server.