Seagate ST19171WC, ST19171DC, ST19171N, ST19171WD manual Scsi bus termination

22 Barracuda 9 Installation Guide, Rev. B

The top example in Figure 2 shows an internal hard disc at one end of the SCSI bus with the SCSI controller at the other end (both are terminated). The bottom example shows two additional SCSI devices connected externally—this means the SCSI con- troller is no longer on the end of the SCSI chain and should not be terminated.

Note. Some controllers prefer to remain terminated even if they are in the middle of the chain. Also, some controllers treat the internal and external chains as separate logical buses. This means you may need to terminate both the first and last devices on both logical buses to achieve proper termination. If necessary, refer to your system or controller documentation to see how this is handled in your particular system.

For information about how to terminate your drive, refer to the appropriate drive-specific section.

Internal SCSI cable

Internal	Internal
SCSI device	SCSI device

Controller

Terminate

Internal SCSI cable

Internal	Internal	Controller
SCSI device	SCSI device

External

SCSI cable

External

SCSI device

External

SCSI device

Terminate

Figure 2. SCSI bus termination