Scsi Configuration Guidelines - Digital Equipment Digital Server 3220 Series System Reference Manual

SCSI Device Configurations

SCSI Configuration Guidelines

•
The SCSI controller has two buses, Channel 1 and Channel 2, which are
typically used as follows:
Location
Internal
channel 1
External
channel 2
•
Both ends of each SCSI bus must be terminated. The main logic board
termination is set automatically. The other termination on Channel 1 is set
on the storage backplane.
•
External SCSI connections must be to the second SCSI bus (Channel 2).
Use the SCSI knockouts at the rear of the server and the supplied SCSI
cable.
•
The Channel 2 bus length is measured from the main logic board (with
termination enabled) Channel 2 connector to the end of the external bus.
•
All devices on a SCSI bus require a unique SCSI ID. SCSI ID 7 is assigned
to the SCSI controller.
•
If a single-ended device is added to a bus with LVD devices, the bus
becomes single-ended.
7-2
Mode SCSI
technology
Single- Wide Ultra
ended SCSI
LVD Wide Ultra2
SCSI
Bus Max.
Speed Devices
40 Mbytes/s 8
80 Mbytes/s 16
Max. Bus
Length
1.5 m
12 m