Western Digital Purple PR1334M, Technical Reference Manual

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WD Purple PR1334M Product Features
2679-800084-A04 RELEASED 5/3/17 (WD CONFIDENTIAL) 21
retry procedure applies only to read data recovery. The Read/Write Retry procedure
performs the actual retry operation.
When an extended retry operation is successful, the controller continues with the
command. The controller clears any changes in track offset or data DAC settings
before the command continues.
3.15 Hot Plug Support
SATA supports hot plugging (also known as “hot swapping”), the ability to swap out a
failed hard drive without having to power down the system or reboot. This capability
contributes to both data availability and serviceability without any associated
downtime, making it a critical feature for extending SATA into enterprise applications.
These WD hard drives support SATA 2.5 hot plugging only in systems where a SATA
hard drive storage backplane is used.
The Serial ATA revision 2.5 specification requires staggered pins for both the hard
drive and drive receptacles. Staggered pins mate the power signals in the
appropriate sequences required for powering up the hot plugged device. These pins
are also specified to handle in excess of the maximum allowed inrush current that
occurs during drive insertion. SATA-compliant devices thus need no further
modification to be hot pluggable and provide the necessary building blocks for a
robust hot plug solution, which typically includes:
n
Device detection even with power downed receptacles (typical of server
applications).
n
Pre-charging resistors to passively limit inrush current during drive insertion.
n
Hot plug controllers to actively limit inrush current during drive insertion.
3.16 Active LED Status
The drive supports external LED requirements. It provides an activity LED output
which is ON during command execution and OFF otherwise.
The drive strength of this open Drain Drive Active signal is that it can sink 12mA to
0.4V Max. It is 5V tolerant, meaning that the external LED may be driven from +5V or
+3.3V so long as the Host system provides a series resistor to limit the LED current to
the lower of 12mA or the rated operating current of the LED. As an example with +5V
and a 2 volt forward drop across a 10mA LED, a 300 Ohm 5% 1/16W resistor would
be suitable. In the case of a 3.3V supply for the same LED, the resistor would be 130
Ohm 5% 1/16W.
The pin corresponding to P11 shall be used for Active LED (see “Device Plug
Connector Pin Definitions” on page 11).
3.17 Fluid Dynamic Bearings (FDB)
Bearing design that incorporates a layer of high-viscosity lubricant instead of ball
bearings in the hard drive spindle motor. As an alternative to conventional ball
bearing technology, FDB designs provide increased non-operational shock resistance,
speed control, and improved acoustics.
3.18 Staggered Spinup and Activity Indication (SATA Power Pin 11)
Note: This feature is available for specific OEM configurations.
SATA device power connector pin 11 is defined as a means by the host to DISABLE
staggered spinup and it may also be used by the device to provide the host with an