Seagate ST19101N/W/WC/WD/DC manual Terminator power, Circuits and data path widths

Cheetah 9 Installation Guide, Rev. B 23

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	External
SCSI device	SCSI device

Terminate

Figure 2. SCSI bus termination

Terminator power

You usually will not need to change this option and can normally leave the drive configured as it was shipped from the factory. For information about how to change the terminator power option on your drive, refer to the appropriate drive-specific section.

I/O circuits and data path widths

•“WD” and “DC” models use differential I/O circuits. You cannot mix these models with single-ended models (“N,” “W,” “WC”) on the same SCSI bus. The circuits are incompatible with each other.

•“W,” “WD,” and “WC” models have a “wide” (16-bit) SCSI data bus rather than the standard (non-wide) 8-bit SCSI data bus; however, you can use these wide drives on a standard (non- wide) 8-bit data bus.