ST11950 and ST12550 Installation Guide, Rev. D 23

Terminating the drive

If you are installing the drive in a system that has other SCSI devices installed, terminate only the end devices on the SCSI chain. A SCSI “device” is any disc drive, scanner, tape backup unit, or other piece of hardware connected to your system using the SCSI bus.

The top example in Figure 5 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 exter- nally—this means the SCSI controller is no longer on the end of the SCSI chain and should not be terminated.

Internal SCSI cable

 

 

 

 

 

 

 

 

Internal

 

Internal

 

Controller

SCSI device

 

SCSI device

 

 

 

 

 

 

 

 

 

 

 

 

 

Terminate

Internal SCSI cable

 

 

 

 

 

 

 

 

Internal

 

Internal

 

Controller

SCSI device

 

SCSI device

 

 

 

 

 

 

 

 

 

 

 

 

 

External

SCSI cable

External

SCSI device

External

SCSI device

Terminate

Figure 5. SCSI bus termination

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Seagate ST12550N/ND/W/WD, ST11950N/ND/W/WD manual Terminating the drive, Scsi bus termination