Internal And External Drive Combinations; Internal Drive Scsi And Power Cable Connections - Digital Equipment DECstation 5000/100 Series Maintenance Manual

Internal and External Drive Combinations

You can connect external drives to the base system SCSI
controller until you have a total of seven devices, whether
internal, external, or a combination of both. The external
drives are connected in a chain that attaches to the base system
SCSI controller using the SCSI connector on the back of the
system unit.
Each drive connected to the base system SCSI controller must
be assigned a unique SCSI ID number from 0 to 6.

Internal Drive SCSI and Power Cable Connections

For each internal SCSI drive:
A SCSI cable connection links each drive to the base system
SCSI controller.
An internal drive power cable connection supplies electrical
power to each internal drive.
Internal Drives 6–3