Synchronized Spindle Operation; Figure 4. Synchronized Drive Interconnect Diagram - Seagate Elite 9 Product Manual

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5.7

Synchronized spindle operation

The synchronized spindle operation allows several drives operating from
the same host to operate their spindles at the same synchronized rotational
rate. Drives operating in a system in synchronized mode increase the
system's capacity and transfer rate in a cost-effective manner.
The interface consists of a twisted-pair cable, which connects the drives
in the synchronized system in a daisy-chain configuration as shown in
Figure 4.
Master Sync
Source
Host
(or other drive)
System
Interface

Figure 4. Synchronized drive interconnect diagram

The host can reconfigure the drive any time after power-up to be the
master or a slave by using the Mode Select command on the Rigid Disc
Drive Geometry page. The master provides the reference signal to which
all other drives phase-lock, including the master. There is only one master
per system, and that can be a drive or the host computer. All drives may
be configured as slaves allowing the host to provide the reference signal.
Each drive also can be configured for the non-synchronized mode in which
it ignores any reference signal that might be present—this is the default
mode as shipped from the factory. Connect the synchronized reference
signal to the host only if the host provides the reference signal. If the host
does not provide the reference signal, do not connect the host.
Elite 9 Product Manual, Rev. C
Sync Interface
J4A
24
Spindle
Control
23
+5V
R T
Drive 1
J4A
24
Spindle
Control
23
+5V
R T
Drive 2
J4A
24
Spindle
Control
23
+5V
R T
Drive n