Seagate ST11950N/ND/W/WD, ST12550N/ND/W/WD manual 32 ST11950 and ST12550 Installation Guide, Rev. D

32 ST11950 and ST12550 Installation Guide, Rev. D

Synchronizing spindles

If you are installing two or more Barracuda drives, you may (optionally) want to synchronize their spindles to reduce the latency associated with switching from one drive to another. Spindle sync cables are used to con- nect the drives.

For N- and ND-type drives, use pins 1 and 2 on the J4 connector to attach the spindle sync cable. Pin 1 provides the reference index signal (REFSIG+) and pin 2 provides ground (GND). See Figure 11.

SCSI
Connector
DC Power	J01
Connector
	Pin 1
	Pin 2
J4	SSC

Spindle Sync Cable Connector (SSC). These pins are used to J4 connect a spindle sync cable.

Spindle sync reference index signal (REFSIG+).

Ground (GND).

Figure 11. Spindle sync jumpers and connectors for ST11950N/ND and ST12550N/ND drives