Information furnished by WD is believed to be accurate and reliable. No license is granted by
implication or otherwise under any patent or patent rights of WD. WD reserves the right to change
specifications at any time without notice.
Western Digital, WD, and the WD logo are registered trademarks in the U.S. and other countries;
and WD Purple, IntelliSeek, NoTouch, Data Lifeguard, CacheFlow, and FIT Lab are trademarks of
Western Digital Technologies, Inc. Other marks may be mentioned herein that belong to other
companies.
Western Digital
3355 Michelson Drive, Suite 100
Irvine, California 92612
2679-800084-A04
Document Control Number Definition:
2679-800xxx-Axx-PxNRD
Doc Control No.Doc Revision LevelNon-Released Document
2.9 Full Model Number Specification ....................................................................................................12
3. PRODUCT FEATURES ....................................................................................................... 13
3.1 SATA 6 Gb/s .....................................................................................................................................14
WD Purple Surveillance Storage is built for 24/7 always-on surveillance in highdefinition security systems that utilize higher hard drive bay counts and up to 64
cameras. Exclusive AllFrame 4K™ technology works with ATA streaming to reduce
error pixilation and video interruptions that occur when desktop hard drives are
incorrectly used as storage in security systems.
1.2Product Features
•Serial ATA (SATA) — Serial ATA (SATA) is the industry standard bus interface for
hard drives. It is designed to replace Parallel ATA, and has many advantages
including increased transfer rate, improved signal integrity, enhanced data protection, and hot plug support.
•AllFrame 4K™ — All WD Purple™ drives are equipped with AllFrame 4K™ tech-
nology, which improves ATA streaming to help reduce frame loss, improve overall
video playback, and increase the number of hard drive bays supported within a
NVR. Help make your surveillance solution future-ready knowing that WD Purple™
drives are ready for ultra high definition cameras.
•Premium Protection -- Designed with tarnish-resistant components, this WD Pur-
ple drive offers premium protection in harsh environments where surveillance systems may be installed.
•IntelliSeek™ — Calculates optimum seek speeds to lower power consumption,
noise, and vibration.
•Dynamic Fly Height Control — Designed to compensate for head/media separa-
tion changes due to temperature and altitude. This feature adds video quality
margins across temperature and altitude changes.
•Perpendicular Magnetic Recording (PMR) — With PMR technology the magneti-
zation of each data bit is aligned vertically to the spinning disk, rather than longitudinally as has been the case in hard drive technology for decades. This enables
more data on a given disk than is possible with conventional longitudinal recording, and provides a platform for future expansion of hard drive densities.
•NoTouch™ Ramp Load Technology — The recording head never touches the disk
media ensuring significantly less wear to the recording head and media as well as
better drive protection in transit.
•Dual Stage Actuator Technology — A head positioning system with dual-stage
actuators that improves positioning accuracy over the data track(s). The primary
stage provides course displacement; the secondary stage uses piezo electric
motion to fine tune the head positioning to a higher degree of precision.
•Advanced Format (AF) — Technology adopted by WD and other drive manufac-
turers as one of multiple ways to continue growing hard drive capacities. AF is a
more efficient media format that enables increased areal densities.
•Native Command Queuing (NCQ ) — Performance of a random I/O workload can
be improved through intelligent re-ordering of the I/O requests so they read/
write to and from the nearest available sectors and minimize the need for additional disk revolutions or head actuator movement. This improvement can be
achieved though Native Command Queuing (NCQ ), which is supported by these
hard drives.
2679-800084-A04RELEASED 5/3/17 (WD CONFIDENTIAL)1
Description and FeaturesWD Purple PR1334M
•Pre-emptive Wear Leveling (PWL) —This WD feature provides a solution for pro-
tecting the recording media against mechanical wear. In cases where the drive is
so busy with incoming commands that it is forced to stay in a same cylinder position for a long time, the PWL control engine initiates forced seeks so that disk
lubricant maintains an even distribution and does not become depleted. This feature ensures reliability for applications that perform a high incidence of read/
write operations at the same physical location on the disk.
•S.M.A.R.T. Command Transport (SCT) — The SCT Command Transport feature set
provides a method for a host to send commands and data to a device and for a
device to send data and status to a host using log pages.
•World Wide Name (WWN) — The World Wide Name (WWN) defined in ATA/
ATAPI-7 is a modification of the IEEE extended unique identifier 64 bit standard
(EUI-64) and is comprised of three major components: naming authority, organizationally unique identifier (OUI) and serial number. WD's OUI is 0014EEh.
•Reliability Features Set-Data Lifeguard™ — Representing WD's ongoing commit-
ment to data protection, Data Lifeguard includes features that enhance the drives
ability to prevent data loss. Data Lifeguard data protection utilities include thermal management, an environmental protection system, and embedded error
detection and repair features that automatically detect, isolate, and repair problem areas that may develop over the extended use of the hard drive. With these
enhanced data reliability features, the drive can perform more accurate monitoring, error repair, and deliver exceptional data security.
•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.
•Active LED Status — The drive supports external LED requirements. It provides an
activity LED output which is ON during command execution and OFF otherwise.
•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.
•Staggered Spin-Up — SATA 3 Gb/s feature that allows the system to control
whether the drive will spin up immediately or wait until the interface is fully ready
(available for specific OEM configurations).
•CacheFlow™ —WD’s unique, multi-generation caching algorithm evaluates the
way data is read from and written to the drive and adapts “on-the-fly” to the optimum read and write caching methods. CacheFlow minimizes disk seek operations
and overheads due to rotational latency. CacheFlow supports sequential and random write cache. With write cache and other CacheFlow features, the user can
cache both read and write data. The cache can hold multiple writes and collectively write them to the hard disk.
•48-bit Logical Block Addressing (LBA) — WD SATA drives support both 48-bit
and 28-bit LBA and CHS-based addressing. LBA is included in advanced BIOS and
operating system device drivers and ensures high capacity disk integration.
2RELEASED 5/3/17 (WD CONFIDENTIAL)2679-800084-A04
WD Purple PR1334M Description and Features
•Power Management — The drive supports the ATA and SATA power management
command set, allowing the host to reduce the power consumption of the drive
by issuing a variety of power management commands.
•Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.) — S.M.A.R.T.
enables a drives internal status to be monitored through diagnostic commands at
the host level and during offline activities. S.M.A.R.T. devices employ data analysis
algorithms that are used to predict the likelihood of some near-term degradation
or fault conditions. When used with a S.M.A.R.T. application, the drive can alert
the host system of a negative reliability status condition. The host system can
then warn the user of the impending risk of data loss and recommend an appropriate action.
•ATA Security — The drive supports the ATA Security Mode Feature set. The ATA
Security Mode feature set allows the user to create a device lock password that
prevents unauthorized hard disk access even if the drive is removed from the host
computer. The correct password must be supplied to the hard drive in order to
access user data. Both the User and Master Password features are supported,
along with the High and Maximum security modes. The Master Password Revision
code is also supported. This feature varies by drive configuration and may not be
available on all configurations.
2679-800084-A04RELEASED 5/3/17 (WD CONFIDENTIAL)3
SpecificationsWD Purple PR1334M
2.0SPECIFICATIONS
2.1Performance Specifications
Performance Class5400 RPM Class
Data Transfer Rate
- Buffer to Host
- Host to/from Disk
Buffer Size64 MB
Error Rate - Unrecoverable<1 in 10
Spindle Start Time
- From Power-on to Drive Ready
- From Power-on to Rotational Speed
Spindle Stop Time<15s average
Load/Unload Cycles (controlled unload at ambient
condition)
1
As used for buffer or cache, one megabyte (MB) = 1,048,576 bytes. As used for transfer rate or interface,
megabyte per second (MB/s) = one million bytes per second, and gigabit per second (Gb/s) = one billion bits
per second. Effective maximum SATA 6 Gb/s transfer rate calculated according to the Serial ATA specification
published by the SATA-IO organization as of the date of this document. Visit www.sata-io.org for details.
2.2Physical Specifications
Specifications represented are of a typical production drive and may be subject to
change or variation without notice.
Physical Specifications
Capacity
InterfaceSATA 6 Gb/s
Number of Disks3
Data Surfaces6
Number of Heads6
Physical bytes per sector4096
Host bytes per sector512
User Sectors per Drive7,814,037,168
Servo TypeEmbedded
Recording Method LDPC Target
2
1
Specifications represented are of a typical production drive and may be subject to change or variation without
notice.
2
As used for storage capacity, one megabyte (MB) = one million bytes, one gigabyte (GB) = one billion bytes,
and one terabyte (TB) = one trillion bytes. Total accessible capacity varies depending on operating
environment. As used for buffer or cache, one megabyte (MB) = 1,048,576 bytes. As used for transfer rate or
interface, megabyte per second (MB/s) = one million bytes per second, and gigabit per second (Gb/s) = one
billion bits per second. Effective maximum SATA 3 Gb/s transfer rate calculated according to the Serial ATA
specification published by the SATA-IO organization as of the date of this document. Visit www.sata-io.org for
details.
1
1
6 Gb/s maximum
175 MB/s sustained (typical)
14
bits read
14.5s average
9s average
300,000
WD40PURX/WD40PURZ/WD40EVRX
4 TB
2.2.1Physical Dimensions
EnglishMetric
DimensionToleranceDimensionTolerance
Height1.028 inchesMAX26.1 mmMAX
Length5.787 inchesMAX147.0 mmMAX
Width4.00 inches±0.01 inch101.6 mm±0.25 mm
Weight1.40 pounds±10%0.635kg±10%
4RELEASED 5/3/17 (WD CONFIDENTIAL)2679-800084-A04
WD Purple PR1334M Specifications
2.3Mechanical Specifications
Figure 2-1 shows the mounting dimensions and locations of the screw holes for the
drive.
All values are typical (25°C, 5.0V, and 12V input). 3.3V Serial ATA power not utilized in
this product.
Operating ModeMean CurrentPower, Average
12 VDC5 VDC
Spinup (max)1.75 A–24.5 W
Read/Write235 mA335 mA4.5 W
Seek260 mA300 mA4.6 W
POWER MANAGEMENT COMMANDS
Operating ModeMean CurrentPower, Average
12 VDC5 VDC
Idle
Standby7 mA70 mA0.4 W
Sleep7 mA70 mA0.4 W
230 mA260 mA4.1 W
2.4.2Input Voltage Requirements
The input voltage requirements are +5.0V ± 5% and +12.0V ± 10%.
2.4.3Ripple
+12 VDC+5 VDC
Maximum
Frequency
200 mV (peak-to-peak)
0-30 MHz
100 mV (peak-to-peak)
0-30 MHz
2.4.4Power Connectors and Cables
SATA Connectors
For information on SATA data connectors, refer to the Serial ATA 1.0 specification
available for download at www.serialata.org.
At the time of this printing, there are no published standards for SATA power/mating
connectors or power/data cable wire gauges.
Cabling Requirements for SATA
The SATA cable consists of four conductors in two differential pairs. The cable may
also include drain wires to be terminated to the ground pins in the SATA cable
receptacle connectors. See the SATA 1.0 specification for cable specifications. The
cable's maximum length is one meter.
6RELEASED 5/3/17 (WD CONFIDENTIAL)2679-800084-A04
WD Purple PR1334M Specifications
2.5Environmental Specifications
2.5.1Shock and Vibration
Table 1. Shock and Vibration
Shock
Operating30G, 2 ms (read/write)
65G, 2 ms (read)
Non-operating (2 ms)250G
Note: Half-sine wave, measured without shock isolation and without non-recoverable errors.
Vibration
OperatingLinear: 20-300 Hz, 0.75G (0 to peak)
Random: 0.004 g2 /Hz (10-300 Hz)
Non-operatingLinear: 20-500 Hz, 4.0G (0 to peak)
2
Random: 0.05 g
Sweep Rate0.5 octave/minute minimum
Rotational Vibration
12.5 rad/sec
Frequency (Hz) 2020030090014001500
(Rad/sec2)2/Hz
Drive Generated Vibration
Operating0.2 gm-mm average with the drive in an unconstrained condition
Rotational Shock Non-Operating
Amplitude20K rad/sec
Duration2 ms
2
based on the following PSD profile maintaining < 20% degradation:
0.0350.0350.20.20.0020.002
/Hz (10-300 Hz)
2
Operating Vibration
Drives are tested by applying a random excitation in each linear axis, one axis at a
time. The drive incurs no physical damage and no hard errors while subjected to
continuous vibration not exceeding the level listed in Table 1. Operating performance
may degrade during periods of exposure to continuous vibration.
Non-Operating Vibration
Note: This specification applies to handling and transportation of unmounted drives.
Drives are tested by applying a random excitation in each linear axis, one axis at a
time. The drive incurs no physical damage when subjected to continuous vibration
not exceeding the level listed in Table 1.
Packaged Shock and Vibration
The shipping packaging is designed to meet the National/International Safe Transit
Association (N/ISTA) standards for packaged products. The drive incurs no physical
damage when subjected to the N/ISTA standards.
2679-800084-A04RELEASED 5/3/17 (WD CONFIDENTIAL)7
SpecificationsWD Purple PR1334M
2.5.2Temperature and Humidity
The system environment must allow sufficient air flow to limit maximum surface
temperatures as defined. AFR can be affected by workload and operating
temperature. See Section 2.6 on page 11 for further details.
Operation
Min-Max Base Casting Temperature
Humidity5-95% RH non-condensing
Thermal Gradient20C/hour (maximum)
Humidity Gradient20%/hour (maximum)
Temperature-40°C to 70°C (-40°F to 158°F)
Humidity5-95% RH non-condensing
Thermal Gradient30C/hour (maximum)
Humidity Gradient20%/hour (maximum)
1
Operating at elevated base casting temperatures will result in a higher AFR.
See Section 2.6 on page 11 for further details.
1
Non-Operation
0C to 65C (32F to 149F)
37.7C (maximum wet bulb)
35C (maximum wet bulb)
8RELEASED 5/3/17 (WD CONFIDENTIAL)2679-800084-A04
WD Purple PR1334M Specifications
2.5.3Thermocouple Location
ComponentLocation
Drive base casting#1, Figure 2
The system environment must allow sufficient air flow to limit maximum base casting temperatures as defined
in Figure 2 below.
Figure 2. Drive Base Casting Thermocouple Location
2679-800084-A04RELEASED 5/3/17 (WD CONFIDENTIAL)9
SpecificationsWD Purple PR1334M
2.5.4Cooling
If forced air cooling is required, the drive must be positioned to receive airflow from
one or more fans as indicated in Figure 3.
Figure 3. Forced Airflow Direction
$%29('5,9(
%(/2:'5,9(
2.5.5Atmospheric Pressure
Altitude
Operating-1,000 feet to 10,000 feet (-305M to 3,050M)
Non-operating-1,000 feet to 40,000 feet (-305M to 12,200M)
2.5.6Acoustics
TYPICAL SOUND POWER LEVEL
Measured per ECMA-74/ISO 7779
Idle Mode (average dBA, no audible pure tones)23
Seek Mode (average dBA) 24
2.5.7RoHS (Restriction of Hazardous Substances)
WD complies with the Restriction of Hazardous Substances (RoHS) Directive 2011/
65/EU of the European Parliament, which is effective in the EU beginning July 8, 2011.
RoHS aims to protect human health and the environment by restricting the use of
certain hazardous substances in new equipment, and consists of restrictions on lead,
mercury, cadmium, and other substances.
The average Annualized Failure Rate (AFR) calculations assumes operation at
nominal voltages, a base casting temperature of 40°C, and the workload
usage of a typical surveillance environment. Workload is defined as the
number of bytes transferred by the user to/from the drive. If the system(s)
that the drive is installed in are not capable of meeting the characteristics
listed below, please use a WD drive that matches your system(s)' capability.
Operating drives outside any of the reliability characteristics listed below will
result in a higher AFR.
Reliability Specification
Average AFR over the Limited Warranty Period0.88%
Reliability Characteristics
Base Casting Temperature40 C
Annual Power on Hours (POH)<=8760
Annualized Workload Rate
1
Annualized Workload Rate = TB transferred x (8760/recorded power-on hours)
1
<=180 TB/Year
2.7Device Plug Connector Pin Definitions
For information on SATA data connectors, including the pin definitions of the SATA
connectors and
the corresponding signal names and signal functions, refer to the latest SATA
specification available for
download at www.serialata.org.
2.8Agency Approvals
PR1334M Regulatory Number (R/N): 800055
These drives meet the standards of the following regulatory agencies:
•Underwriters Laboratories: Bi-National UL Standard CAN/CSA-C22.2 No. 60950/
UL 60950-1. Standard for Safety of Information Technology Equipment, including
Electrical Business Equipment (File E101559).
•TUV NORD CERT GmbH: IEC 60950-1 per EN 60950-1, Standard for Safety of Infor-
mation Technology Equipment, including Electrical Business Equipment. IEC
60065. Standard of Safety for Audio, Video, and Similar Electronic Apparatus.
•CE Compliance for Europe: Complies with EN 55022: 2010 RF/ Conducted Emis-
sions and EN 55024: 2010 Immunity requirements. Including EU Directive 2011/
65/EU RoHS II requirements.
•RCM Compliance for Australia and New Zealand: Verified to comply with AS/NZS
CISPR 22 for RF Emissions as required by the Australian Communications Authority.
•Korean KC Mark: Registered as a Class-B product with the South Korean Ministry
of Information and Communication.
•Taiwan BSMI EMI Certification: Certified as a Class-B product with the Bureau of
SATA 6 Gb/s is the next generation interface for SATA hard drives. It adds to the
functionality of the SATA 1.5 Gb/s interface with the following features:
nNative Command Queuing (NCQ ) — server feature for performance in random I/
O transaction environments. It aggregates many small random data transfers and
allows the disk to reorder the commands in a sequential order for faster access.
nImproved Power Management— provides improved power management
features including Host Initiated SATA Power Management (HIPM) and Device
Initiated SATA Power Management (DIPM).
nStaggered Spin-up — allows the system to control whether the drive will spin up
immediately or wait until the interface is fully ready before spinning up.
nAsynchronous Signal Recovery (ASR) — robustness feature that improves signal
recovery.
nEnclosure Services — defines external enclosure management and support
features.
nBackplane Interconnect — defines how to lay out signal line traces in a
backplane.
nAuto-activate DMA — provides increased command efficiency through
automated activation of the DMA controller.
nDevice Configuration Overlay (DCO) — allows hiding of supported features via a
SATA feature mask.
3.2AllFrame 4K Technology
All WD Purple™ drives are equipped with AllFrame 4K™ technology, which improves
ATA streaming to help reduce frame loss, improve overall video playback, and
increase the number of hard drive bays supported within a NVR. Help make your
surveillance solution future-ready knowing that WD Purple™ drives are ready for ultra
high definition cameras.
3.3IntelliSeek
WD’s unique IntelliSeek technology proactively calculates an optimum seek speed to
eliminate hasty movement of the actuator that produces noise and requires power,
which is common in other drives. With IntelliSeek, the actuator’s movement is
controlled so the head reaches the next target sector just in time to read the next
piece of information, rather than rapidly accelerating and waiting for the drive
rotation to catch up. This smooth motion reduces power usage by more than 60
percent compared with standard drives, as well as quiets seek operation and lowers
vibration.
3.4Dynamic Fly Height Control
This feature is designed to compensate for head/media separation changes due to
temperature and altitude. It adds video quality margins across temperature and
altitude changes.
In perpendicular magnetic recording (PMR), the magnetization of each data bit is
aligned vertically to the spinning disk, rather than longitudinally as has been the case
in hard drive technology for decades. In longitudinal recording, as the bits become
smaller and closer together, they experience an increasing demagnetizing field, much
like two bar magnets that are placed end-to-end repel one another. A property of the
media called coercivity must be increased to counteract the demagnetization to keep
the bits stable under thermal fluctuations; otherwise data corruption may occur over
time. Higher media coercivity has pushed the recording head write field to the limit of
known materials.
In perpendicular recording, the adjacent bits attract instead of repel (as with bar
magnets placed side by side,) creating more thermally stable bits. In addition, the
media contains a magnetically soft underlayer (SUL) beneath the recording layer. This
SUL allows a larger effective write field, thus higher coercivity media, enabling further
increases in density. Lastly, because of the vertical orientation of the bits, the PMR
recording layer tends to be thicker than that used for longitudinal recording,
providing increased signal for the read heads. All of these benefits enable WD
engineers to reliably pack more data on a given disk than is possible with
conventional longitudinal recording.
3.6NoTouch Ramp Load Technology
Parks the recording heads off the disk surface during spin up, spin down and when
the drive is off. This ensures the recording head never touches the disk surface
resulting in improved long term reliability due to less head wear, and improved nonoperational shock tolerance.
3.7Dual Stage Actuator Technology
A head positioning system with dual-stage actuators that improves positioning
accuracy over the data track(s). The primary stage provides course displacement; the
secondary stage uses piezo electric motion to fine tune the head positioning to a
higher degree of precision.
3.8Advanced Format (AF)
Advanced Format (AF) technology is adopted by WD and other drive manufacturers
as one of multiple ways to continue growing hard drive capacities. AF is a more
efficient media format that enables increased areal densities.
In AF, each physical sector is composed of eight 512 byte logical sectors, totaling
4096 bytes. WD is shipping AF drives as 512 Byte Emulated Devices until full
operating system support for the AF host interface is available. 512 Byte Emulated
Device drives are backward compatible with 512 byte sector accesses.
WD AF hard drives may require you to run the WD Align software utility after you
install your operating system or partition and format the drive as a secondary drive.
WD Align software aligns partitions on the AF drive to ensure it provides full
performance for certain configurations. Go to www.wdc.com/advformat for important
configuration and installation guidelines.
These drives support Native Command Queuing. NCQ is a true Enterprise feature for
environments such as database, Web servers, and e-mail servers.
Performance of a random I/O workload can be improved through intelligent reordering of the I/O requests so they read/write to and from the nearest available
sectors and minimize the need for additional disk revolutions or head actuator
movement. This improvement is achieved though Native Command Queuing (NCQ ).
NCQ allows the drive to re-order read commands, thereby increasing random read
IOPs. Additional NCQ features that can prove beneficial include a Write Cache
disabled IOP increase and a queuing implementation built upon an existing, highly
automated cache architecture. Queued reads in NCQ leverage the same re-ordering
schemes used for write caching. The firmware design maintains the “order” of
overlapping/colliding queued commands. NCQ is designed to excel in multithreaded environments with high random I/O loads.
3.10Pre-emptive Wear Leveling (PWL)
This WD feature provides a solution for protecting the recording media against
mechanical wear. In cases where the drive is so busy with incoming commands that it
is forced to stay in a same cylinder position for a long time, the PWL control engine
initiates forced seeks so that disk lubricant maintains an even distribution and does
not become depleted. This feature ensures reliability for applications that perform a
high incidence of read/write operations at the same physical location on the disk.
3.11S.M.A.R.T. Command Transport (SCT)
The SCT Command Transport feature set provides a method for a host to send
commands and data to a device and for a device to send data and status to a host
using log pages. Standard ATA commands may be interspersed with SCT commands,
but SCT commands cannot be nested. SCT commands that do not require a
subsequent data transfer operation are not interspersed with any ATA commands or
each other.
The SCT Command Transport feature set provides a method for a host to send
commands and data to a device and for a device to send data and status to a host
using log pages. This capability is used to pass commands through a driver interface
or a bridge where new or unknown commands may be filtered and not passed to the
drive. SCT is also used for issuing commands that require more than 8 parameter
bytes. ATA8-ACS provides detailed information on the usage and capabilities of SCT.
The SCT feature set includes the following commands:
nWrite Same
nTemperature Reporting
3.11.1Write Same
The Write Same command allows the host to erase the media, or write a pattern
repeatedly across the media, with a minimum of data transfer from the host. The host
can clear the entire media to zeros or a specific pattern by sending this command
with the pattern as a parameter—no data transfer is necessary. Write Same can write
the entire media, or just a portion of the media. The host can monitor the progress of
the Write Same by issuing SCT Status requests. This frees the host system to do other
tasks while the media is being cleared.
3.11.2Temperature Reporting
The SCT Temperature Reporting (SCT TR) feature allows a host system to access
temperature information in the drive. The S.M.A.R.T. temperature value is reported
within ±3°C of the base casting temperature. This information can been used to
control fans or adjust the usage of various system components to keep the drive
within its normal operating temperature. Applications include Enterprise, Laptop,
Desktop and Consumer Electronics. SCT TR reports the maximum and minimum
sustained operating limits, warning level limits, and drive damage limits. In addition to
reporting the limits, SCT TR returns the current drive temperature (a temperature
history which the host can use to predict heating or cooling trends) and the maximum
temperature achieved during the lifetime of the drive as well as the highest
temperature achieved since the power was applied to the drive. Detailed information
on this capability can be found in ATA8-ACS.
3.12World Wide Name (WWN)
It has become a critical requirement that hard drives be uniquely identified by
computer systems. This allows a drive to maintain its identity as it is transported from
system to system or placed on a network. IEEE has defined a format for serial numbers
that is widely recognized in the computing industry by adding World Wide Name
(WWN) to ATA/ATAPI-7 in 2002.
The World Wide Name (WWN) defined in ATA/ATAPI-7 is a modification of the IEEE
Extended Unique Identifier 64 bit standard (EUI-64) and is comprised of three major
components: naming authority, organizationally unique identifier (OUI) and serial
number. WD's OUI is 0014EEh.
3.13Reliability Features Set
3.13.1Data Lifeguard™
Representing WD's ongoing commitment to data protection, Data Lifeguard includes
features that enhance the drives ability to prevent data loss. Data Lifeguard data
protection utilities include thermal management, an environmental protection
system, and embedded error detection and repair features that automatically detect,
isolate, and repair problem areas that may develop over the extended use of the hard
drive. With these enhanced data reliability features, the drive can perform more
accurate monitoring, error repair, and deliver exceptional data security.
All WD drives are defect-free and low-level formatted at the factory. After prolonged
use, any drive, including a WD drive, may develop defects. If you continue receiving
data errors in any given file, use the Data Lifeguard Diagnostics utility to recover,
relocate and rewrite the user data to the nearest spare sector and maintain a
secondary defect list.
CAUTION: As with all format utilities, some options in the Data Lifeguard Diagnostics
utility will overwrite user data.
Download the latest versions of the Data Lifeguard Diagnostic and Data Lifeguard
Tools programs at support.wdc.com.
The drive is designed with Thermal Management features for high reliability.
nState-of-the-art mechanical design—Mechanical design is optimized to reduce
the drives temperature. State-of-the-art thermal dissipation and windage design
is employed.
nClosed loop servo management—Thermal management monitors the drive
temperature and can control servo operations to maintain a stable operating
temperature under high temperature conditions. This is a closed loop servo and
thermal control system.
nS.M.A.R.T. HDA Temperature Attribute—The S.M.A.R.T. HDA Temperature
Attribute is supported. The S.M.A.R.T. temperature value is reported within ±3°C
of the base casting temperature.
nDucted airflow—Provides protection to the Read/Write element from heated air.
This dual filter system protects the inside environment of the drive from
contamination. System features include:
nDual Filtration System to ensure fast clean-up times
nDirected airflow to maximize mechanical cooling
nIncrease casting surface area to maximize cooling
nDucted air flow to protect Read Rite elements from heated air
nBreather filter located at low pressure area
nEnhanced heat dissipation
3.13.4Recoverable Errors
A sector marked for repair is written back to the same location. The sector is then
read several times to be sure that it was written correctly and that there is no media
damage at its location (sector test). If the sector does not easily and consistently read
correctly, the sector is then relocated with original data.
3.13.5Unrecoverable Errors
If an unrecoverable error is found during the offline scan, the sector is marked. Future
reads from this location will continue to perform full error recovery. However, the
next write to this location will perform a sector test to be sure the media is not
damaged, and the sector relocated if the sector test fails.
3.13.6Self Test
Self Test is a quick way to determine the operation status of a drive. The following
Self Tests are supported:
nQuick Test: Completes in less than two minutes.
nExtended Test: Tests all the critical subsystems of the drive.
nConveyance Test: Quickly identifies issues caused by handling damage.
nSelective Test: Scans host-defined sections of the drive.
The test may be run to completion or be performed as a background task as the drive
processes other commands from the host. The host may then poll the drive for
runtime status and test results. Since the test is embedded in the drives firmware, it is
always available, requires no installation and can be faster and more effective than a
software-based drive test.
3.13.7ATA Error Logging
ATA Error Logging provides an industry standard means to record error events and
supporting information that is then accessible by the host. The event record includes
the exact command that caused the failure, the response of the drive, the time of the
event and information about the four commands immediately prior to the errant
command. Error Logging can reliably and quickly determine whether a system
problem is the result of a hard drive failure or other component malfunction. Error
Logging retains total error count for the life of the drive and complete records for the
last five errors.
Every WD drive undergoes factory-level intelligent burn in, which thoroughly tests for
and maps out defective sectors on the media before the drive leaves the
manufacturing facility. Following the factory tests, a primary defect list is created. The
list contains the cylinder, head, and sector numbers for all defects.
Defects managed at the factory are sector slipped. Grown defects that can occur in
the field are mapped out by relocation to spare sectors on the inner cylinders of the
drive.
3.14Automatic Defect Retirement
The automatic defect retirement feature automatically maps out defective sectors
while reading or writing. If a defective sector appears, the drive finds a spare sector.
The following item is specific to automatic defect retirement on writes (write autorelocation):
nData is always written to disk (using automatic defect retirement if required) and
no error is reported.
The following item is specific to automatic defect retirement on reads (read autorelocation):
nWhen host retries are enabled, the drive will internally flag any unrecoverable
errors (DAMNF or ECC). This flagging allows subsequent write commands to this
location to relocate the sector only if the sector test fails.
ECC On-the-Fly – If an ECC error occurs, the drive attempts to correct it on-the-fly
without retries. Data can be corrected in this manner without performance penalty.
The details of the correction algorithm appear in the next section.
Preamp Thermal Asperity Compensation – A Thermal Asperity (TA) is a baseline shift in
the readback signal due to heating of the magnetoresistive stripe on the head as a
result of physical contact with the disk or a particle. The preamp circuit has the ability
to detect and compensate for thermal asperities. When an error cannot be corrected
by ECC On-the-Fly, another retry is performed, where the preamp with its thermal
asperity detection feature determines if the error is due to a thermal asperity. Once
the preamp determines that the error is due to thermal asperity, preamp
compensation is enabled. If preamp compensation alone is not enough to recover,
then the channel performs a series of TA-specific recoveries.
Read/Write Retry Procedure – This retry procedure is used by all disk controller error
types. If the procedure succeeds in reading or writing the sector being tried, then
recovery is complete and the controller continues with the command. Each retry
operation also checks for servo errors. The procedure ends when error recovery is
achieved or when all possible retries have been attempted.
Extended Read Retry Procedure – This retry procedure tries combinations of
positive/negative track offsets and data DAC manipulations to recover the data. This
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.
3.15Hot 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:
nDevice detection even with power downed receptacles (typical of server
applications).
nPre-charging resistors to passively limit inrush current during drive insertion.
nHot plug controllers to actively limit inrush current during drive insertion.
3.16Active 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).
3.17Fluid 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.
3.18Staggered 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
activity indication. According to the SATA spec, “Staggered Spin-up Disable and
Activity Signal shall not be enabled at the same time.”
3.18.1Staggered Spinup
When multiple disks are installed in an enclosure, it is desirable to provide a simple
mechanism by which a subsystem controller can sequence hard drive initialization to
minimize the current load presented during power up. Staggered spinup provides
this mechanism by preventing the hard drives from spinning up until after successful
PHY initialization (i.e., after PHY enters DP7:DR_Ready state).
Staggered spinup is only applicable during initial power-up. If a drive is spun down
using ATA commands—as a result of having been placed in Standby or Sleep power
modes, for example—the drive shall spin up following the rules that govern spinup
from low power modes described in ATA/ATAPI-6 or later.
3.18.2Activity Indication
The host controller through SATA power pin 11 may access storage device status and
activity. The signal provided by the device for activity indication is a low-voltage lowcurrent signal. It is not suitable for directly driving an LED. A buffer circuit external to
the device must be employed to drive the LED. The activity signal is based on an
open-collector or open-drain active low driver. The device shall tolerate the activity
signal being shorted to ground.
3.19CacheFlow™
CacheFlow is WD’s unique, multi-generation disk caching system. It incorporates read
cache with write cache.
WD designed CacheFlow to obtain maximum performance with today’s most popular
operating systems and applications. CacheFlow increases performance over prior
caching algorithms by increasing the number of times that requested data is in the
cache. This reduces the number of host commands that require actual media access
thereby improving overall drive performance.
Typical applications perform a variety of access patterns, such as random, sequential,
and repetitive. CacheFlow is designed to dynamically adapt to the changes in access
patterns that occur during the course of application execution.
Random mode is the default operational mode for CacheFlow. Once CacheFlow
detects a sequential access pattern, it leaves random mode. CacheFlow also
performs predictive read operations to increase the probability that data requested in
future commands already exists in the cache.
CacheFlow partitions the buffer into multiple segments to allow for the fact that
applications may access multiple non-contiguous areas on the disk. CacheFlow tracks
the amount of valid data in each segment and controls the deallocation of segments
to maximize drive performance.
3.19.1Write Cache
CacheFlow is designed to improve both single and multi-sector write performance by
reducing delays caused by seek time and rotational latency.
The write cache adaptively detects random and sequential access patterns during
application execution.
If a defective sector is found during a write cache operation, that sector is
automatically relocated before the write occurs.
3.19.2Read Cache
CacheFlow implements a multiple segment read cache. Cache segments are assigned
to read commands as they are received from the host.
Each read segment consists of pre and post read sectors in addition to the hostrequested sectors. This maximizes the amount of cache data in the drives buffer,
thereby increasing the likelihood of cache hits and improving overall performance.
3.2048-bit Logical Block Addressing (LBA)
The 48-bit Address feature set allows devices with capacities up to approximately 281
tera sectors or approximately 144 peta bytes. In addition, the number of sectors that
may be transferred by a single command are increased by increasing the allowable
sector count to 16 bits.
LBA High (exp)LBA Mid (exp)LBA Low (exp)LBA HighLBA MidLBA Low
16-bit Sector Count
Bits (15:8)Bits (7:0)
Sector Count
(exp)
Sector Count
3.21Power Management
This drive supports the ATA power management commands that lower the average
power consumption of the hard drives. For example, to take advantage of the lower
power consumption modes of the drive, an energy efficient host system could
implement a power management scheme that issues a Standby Immediate command
when a host resident disk inactivity timer expires. The Standby Immediate command
causes the drive to spin down and enter a low-power mode. Subsequent disk access
commands would cause the drive to spin up and execute the new command. To
avoid excessive wear on the drive due to the starting and stopping of the HDA, set
the host’s disk inactivity timer to no shorter than ten minutes.
The drive also supports the SATA power management feature that lowers the average
power consumption of the SATA interface.
3.22Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.)
S.M.A.R.T. helps you monitor a drives internal status through diagnostic commands at
the host level.
The drive monitors Read Error Rate, Start/Stop Count, Re-allocated Sector Count,
Seek Error Rate, Power-on Hours Count, Spin-up Retry Count, Drive Calibration Retry
Count, Drive Power Cycle Count, Offline Scan Uncorrectable Sector Count, CRC Error
Rate, Multi-zone Error Rate, Spin-up Time, Relocation Event Count, and Current
Pending Sector Count. The hard drive updates and stores these attributes in the
reserved area of the disk. The drive also stores a set of attribute thresholds that
correspond to the calculated attribute values. Each attribute threshold indicates the
point at which its corresponding attribute value achieves a negative reliability status.
The Security Mode feature set allows the user to create a device lock password that
prevents unauthorized hard drive access even if the drive is removed from the
computer. This feature varies by drive configuration and may not be available on all
configurations.
3.23.1Master and User Passwords
The manufacturer/dealer can set a master password using the Security Set Password
command, without enabling the device lock function. The user password should be
given or changed by a system user.
Master Password Identifier is supported and set to a default value of 00FE. If a Master
Password is set via a Security Set Password Command, a valid Master Password
Revision code value of 0001h – FFFEh must be used. A Master Password Identifier of
0000h is ignored.
When the master password is set, the drive does not enable the device lock function.
When the user password is set, the drive enables the device lock function, and the
drive is locked after the next power on reset or hard reset.
3.23.2Security Levels
High - If High level security is set and the user password is forgotten, the master
password can be used to unlock the drive and access the data.
Maximum - If Maximum level security is set and the user password is forgotten, data
access is impossible. Only the master password with a Security Erase Unit command
can unlock the drive when the device lock function is enabled and the user password
has been forgotten. When the Security Erase Unit command is used to unlock the
drive, all user data is erased.
Table 5 lists the hexadecimal codes specific to each ATA-8 command supported by
these hard drives. Refer to the D1699 ATA8-ACS specification for full details on each
command.
Table 6 lists the hexadecimal codes specific to each SATA command supported by
these hard drives. Refer to the SATA specification for full details on each command.
Table 6. SATA Command Opcodes
COMMANDHEX OPCODE
READ FPDMA QUEUED60
WRITE FPDMA QUEUED61
4.1.3Obsolete Commands
Table 7 lists the hexadecimal codes specific to each obsolete command supported by
these hard drives.
Table 7. Obsolete Command Opcodes
COMMANDHEX OPCODE
INITIALIZE DEVICE PARAMETERS91
READ LONG22
RECALIBRATE10
SEEK70
WRITE LONG32
4.1.4SCT Commands
SCT commands provide capabilities not covered in ATA/ATAPI-7 for commands that
do not fit the ATA command delivery model. Some SCT commands report completion
when the command begins execution. Execution progress for these commands may
be checked by requesting SCT status. For instance, the host can track the progress of
a Write Same command by issuing a status request once per minute. See ATA8-ACS
for a full description of SCT.
Table 8. SCT Action Codes
ACTION CODEDESCRIPTION
0000hRESERVED
0001hLong Sector Access
0002hWrite Same
0004hFeatures Control
0005hSCT Data Tables
0006hVendor specific
0007hSCT BIST
C000hFFFFh Vendor specific
4.2S.M.A.R.T. (B0h)
The S.M.A.R.T. command provides access to attribute values, S.M.A.R.T. status, and
other S.M.A.R.T. information. These commands can be used for logging and reporting
purposes, and for accommodating special user needs.
Prior to writing the S.M.A.R.T. command to the Command Register, the host must
write key values into the LBA Mid and LBA High Registers (4Fh, C2h) or the command
will be aborted and an error will be reported.
The S.M.A.R.T. command has several sub-commands that are selectable via the
Features Register when the host issues the S.M.A.R.T. command. To select a subcommand, the host must write the appropriate sub-command code to the Features
Register before issuing the S.M.A.R.T. command. The sub-commands and their
respective codes are listed below. For more detailed information on executing
S.M.A.R.T. commands, see the ATA-7 specification.
4.2.1Read Attribute Values Sub-Command
This command returns a sector of data with the drives S.M.A.R.T. data structure.
Table 9. Definitions for the 512 Bytes.
BYTEVALUEDESCRIPTION
0 - 10001hS.M.A.R.T. Data Structure Revision
2 -361XXS.M.A.R.T. Attribute Data
135 - 361XXS.M.A.R.T. Attribute Data
362XXOffline data collection status
0Xh OL disabled
8Xh OL enabled
X0h scan not run
X2h scan complete
X4h scan suspended
363XXSelf-Test execution status byte.
364 - 365XX
366XX
36707Bh
368 - 3690003h
37001h
371XX
372XX
373XX
374XX
375 - 510XX
511XX
X5h scan aborted
00hThe previous self-test routine completed without error or no
01hThe self-test routine was aborted by the host
02hThe self-test routine was interrupted by the host with a hard
03hA fatal error or unknown test error occurred while the device
04hThe previous self-test completed having a test element that
05hThe previous self-test completed having a test element that
06hThe previous self-test completed having a test element that
07hThe previous self-test completed having a test element that
08hThe previous self-test completed having a test element that
09-0Eh Reserved
0FhSelf-test routine in progress
Total time in seconds to complete offline data collection activity
Reserved
Offline data collection capability. Bits are as follows:
S.M.A.R.T. Capability. Bits are as follows:
Error logging capability. Bits are as follows:
Reserved
Short self-test routine completion time in minutes
Extended self-test routine completion time in minutes
Conveyance self-test routine completion time in minutes
Reserved
Checksum
self-test has ever been run
or soft reset
was executing its self-test routine. The device was unable to
complete the self-test routine.
failed. The test element that failed is not known.
failed. The electrical element of the test failed.
failed. The servo (and/or seek) test element of the test failed.
failed. The read element of the test failed.
failed. The element damage is suspected to be caused by
handling.
Attributes that use the Pre-Failure/Advisory Bit Set can predict potential future
degrading or faulty conditions. Attributes with the Failure/Advisory Bit Clear are used
for informational purposes only, they do not indicate impending drive failure.
The S.M.A.R.T. data saving process is a background task. After a pre-determined idle
period, the self-monitoring data is automatically saved to the disk.
Bit 15-8: 80h
Bit 7-0: 00h: Reserved
01h-FFh = Maximum number of logical sectors that shall be
transferred per DRQ data block on READ/WRITE
MULTIPLE commands
48Trusted Computing feature set options
Bit 15: Shall be cleared to zero
Bit 14: Shall be set to one
Bit 13-1: Reserved for the Trusted Computing Group
Bit 0: If set, Trusted Computing feature set is supported
49Capabilities
Bit 15-14: Reserved for the IDENTIFY PACKET DEVICE
command.
Bit 13: If set, Standby timer values as specified in this
standard are supported.
0 = Standby timer values shall be managed by the device
Bit 12: Reserved for the IDENTIFY PACKET DEVICE
command
Bit 11: If set, IORDY supported
Bit 10: If set, IORDY may be disabled
Bit 9: If set, LBA supported
Bit 8: If set, DMA supported
Bit 7-2: Reserved
Bit 1: Current Long Physical Alignment Setting
50Capabilities
Bit 15: Shall be cleared to zero.
Bit 14: Shall be set to one.
Bit 13-2: Reserved.
Bit 1: Obsolete
Bit 0: Shall be set to one to indicate a device specific
Standby timer value minimum
51-52Obsolete0
53Additional Words Valid
Bit 8-15: Free-fall Control Sensitivity
00h = Vendor’s recommended setting
01h-FFh = Sensitivity level. A larger number is a
more sensitive setting.
Bit 7-3: Reserved
Bit 2: If set, the fields reported in word 88 are valid
Bit 1: If set, the fields reported in words 70-64 are valid
Bit 0: Obsolete
Bit 15: 1=The BLOCK ERASE EXT command is supported
Bit 14: 1= The OVERWRITE EXT command is supported
Bit 13: 1=The CRYPTO Scramble EXT command is
supported
Bit 12: 1=The Sanitize feature set is supported
Bit 9-11 Reserved
Bit 8: 1=Multiple local sector setting is valid
Bit 0-7: Current setting for number of logical sectors that
shall be transferred per DRQ data block on READ/WRITE
Multiple commands
60-61Total number of user addressable logical sectors for 28 bit
commands (DWord)
62Obsolete0
63Multi-Word DMA Transfer Mode Supported
Bit 15-11: Reserved
Bit 10: If set, Multiword DMA mode 2 is selected
Bit 9: If set, Multiword DMA mode 1 is selected
Bit 8: If set, Multiword DMA mode 0 is selected
Bit 7-3: Reserved
Bit 2: If set, Multiword DMA mode 2
Bit 1: If set, Multiword DMA mode 1
Bit 0: If set, Multiword DMA mode 0
64Advanced PIO Modes Supported
Bits 0-7: PIO Modes supported
65Min. Multi-Word DMA Transfer Cycle Time (ns)
Bit 15-0: Cycle time in nanoseconds
66Manufacturer Recommended Multi-Word DMA Cycle Time
Bit 15-0: Cycle time in nanoseconds
67Min. PIO Transfer Cycle Time without flow control
Bit 15-0: Cycle time in nanoseconds
68Min. PIO Transfer Cycle Time with IORDY flow control
Bit 15-0: Cycle time in nanoseconds
69Additional Supported
Bit 15: If set, CFast Specification Support
Bit 14: If set, Deterministic data in trimmed LBA range(s) is
supported
Bit 13: If set, Long Physical Sector Alignment Error
Reporting Control is supported
Bit 12: If set, DEVICE CONFIGURATION IDENTIFY DMA
and DEVICE CONFIGURATION SET DMA are supported
Bit 11: If set, READ BUFFER DMA is supported
Bit 10: If set, WRITE BUFFER DMA is supported
Bit 9: If set, SET MAX SET PASSWORD DMA and SET
MAX UNLOCK DMA are supported
Bit 8: If set, DOWNLOAD MICROC
Bit 6: If set, Optional ATA device 28-bit commands
supportedODE DMA is supported
Bit 7: If set, Reserved for IEEE 1667
Bit 5: If set, Trimmed LBA range(s) returning zeroed data is
supported
Bit 4: If set, Device Encrypts All User Data
Bit 3: If set, Extended Number of User Addressable Sectors
is supported
Bit 2-0: Reserved
70Reserved0
71-74Reserved for the Identify Packet Device command0
75Queue Depth
Bit 15-5: Reserved
Bit 4-0: Maximum queue depth - 1
Bit 15-13: Reserved
Bit 12: Supports Native Command Queuing priority
information
Bit 11: Supports Unload while NCQ commands
outstanding
Bit 10: Supports Phy event counters
Bit 9: Supports receipt of host-initiated interface power
management requests
Bit 8: Supports Native Command Queuing (NCQ)
Bit 7-3: Reserved for future Serial ATA signaling speed
grades
Bit 7-4: Reserved for future Serial ATA signaling speed
grades
Bit 3: If set, Supports Serial ATA Gen3 signaling speed (6
Gb/s)
Bit 2: 1= Supports Serial ATA Gen2 signaling speed
(3 Gb/s)
Bit 1: 1= Supports Serial ATA Gen1 signaling speed
(1.5 Gb/s)
Bit 0: Shall be cleared to zero
77Reserved for Serial ATA0006h
78Serial ATA Features Supported
Bit 7-15: Reserved for Serial ATA
Bit 6: If set, device supports software settings preservation
Bit 5: Reserved for Serial ATA
Bit 4: If set, device supports in-order data delivery
Bit 3: If set, device supports initiating power management
Bit 2: If set, device supports DMA Setup Auto-activation
Bit 1: If set, device supports non-zero buffer offsets
Bit 0: Cleared to zero
79Serial ATA Features Enabled
Bits 7-15: Reserved for Serial ATA
Bit 6: If set, software settings preservation enabled
Bit 5: Reserved for Serial ATA
Bit 4: If set, In-order data delivery enabled
Bit 3: If set, device initiated power management enabled
Bit 2: If set, DMA Setup Auto-activation enabled
Bit 1: If set, non-zero buffer offsets enabled
Bit 0: Cleared to zero
80Major Version Number
Bit 15-10: Reserved
Bit 9: if set, supports ACS-2
Bit 8: if set, supports ATA8-ACS
Bit 7: if set, supports ATA/ATAPI-7
Bit 6: if set, supports ATA/ATAPI-6
Bit 5: if set, supports ATA/ATAPI-5
Bit 4 –1: Obsolete
Bit 0: Reserved
81Minor Version Number006Dh
82Command and feature sets supported
Bit 14: If set, NOP command supported
Bit 13: If set, Read buffer command supported
Bit 12: If set, Write buffer command supported
Bit 11: Obsolete
Bit 10: If set, Host Protected Area Feature Set supported
Bit 9: If set, Device Reset command supported
Bit 8: If set, Service interrupt supported
Bit 7: If set, Release interrupt supported
Bit 6: If set, look-ahead supported
Bit 5: If set, Write Cache supported
Bit 4: Cleared to 0 to indicate that the PACKET feature set
is not supported.
Bit 3: If set, mandatory Power Management Feature Set
supported
Bit 2: Obsolete
Bit 1: If set, Security Feature Set supported
Bit 0: If set, SMART Feature Set supported
Bit 15: Shall be cleared to 0
Bit 14: Shall be set to 1
Bit 13: If set, Flush Cache EXT command supported
Bit 12: If set, mandatory Flush Cache command supported
Bit 11: If set, DCO feature set supported
Bit 10: If set, 48-bit Address Feature Set supported
Bit 9: Not supported
Bit 8: If set, Set Max Security Extension supported
Bit 7: Reserved
Bit 6: If set, Set Features subcommand required to spin-up
after power-up
Bit 5: If set, Power-Up In Standby feature set supported
Bit 4: Obsolete
Bit 3: If set, Advanced Power Management feature set
supported
Bit 2: If set, CFA feature set supported
Bit 1: If set, Read/Write DMA Queued supported
Bit 0: If set, Download Microcode command supported
84Command and feature sets supported
Bit 15: Shall be cleared to zero
Bit 14: Shall be set to one
Bit 13: If set, Idle Immediate with Unload Feature supported
Bit 12: Reserved
Bit 11: Reserved
Bit 9-10: Obsolete
Bit 8: If set, 64-bit World wide name supported
Bit 7: If set, Write DMA Queued FUA EXT command
supported
Bit 6: If set, Write DMA FUA EXT and Write Multiple FUA
EXT commands supported
Bit 5: If set, General Purpose Logging feature set supported
Bit 4: If set, Streaming Feature Set supported
Bit 3: Obsolete
Bit 2: If set, Media serial number supported
Bit 1: If set, SMART Self-Test supported
Bit 0: If set, SMART Error Logging supported
85Command and feature sets supported or enabled
Bit 15: Obsolete
Bit 14: If set, NOP command supported
Bit 13: If set, Read Buffer command supported
Bit 12: If set, Write Buffer command supported
Bit 11: Obsolete
Bit 10: If set, Host Protected Area has been established
Bit 9: If set, DEVICE RESET command supported
Bit 8: If set, SERVICE interrupt enabled
Bit 7: If set, Release Interrupt enabled
Bit 6: If set, Read look-ahead enabled
Bit 5: If set, Volatile Write cache enabled
Bit 4: Cleared to 0 to indicate that the PACKET feature set
is not supported
Bit 3: Set to 1 to indicate that the Mandatory Power
Management feature set is supported
Bit 2: Obsolete
Bit 1: If set, Security Feature Set enabled
Bit 0: If set, SMART Feature Set enabled
86Commands and feature sets supported or enabled
Bit 15: If set, Words 119-120 are valid
Bit 14: Reserved
Bit 13: If set, Flush Cache EXT command supported
Bit 12: If set, Flush Cache command supported
Bit 11: If set, Device Configuration Overlay supported
Bit 10: If set, 48-bit Address Feature Set supported
Bit 9: Not supported
Bit 8: If set, Set Max Security Extension enabled by Set Max
Set Password
Bit 7: Reserved
Bit 6: If set, Set Features subcommand required to spin-up
after power-up
Bit 5: If set, Power-Up In Standby feature set enabled
Bit 4: Obsolete
Bit 3: If set, Advanced Power Management feature set
enabled
Bit 2: If set, CFA Feature Set enabled
Bit 1: If set, Read/Write DMA Queued command supported
Bit 0: If set, Download Microcode command supported
Bit 15: Shall be cleared to zero
Bit 14: Shall be set to 1
Bit 13: If set, Idle Immediate with Unload Feature supported
Bit 12: Reserved
Bit 11: Reserved
Bit 9-10: Obsolete
Bit 8: If set, 64-bit World wide name supported
Bit 7: If set, Write DMA Queued FUA EXT command
supported
Bit 6: If set, Write DMA FUA EXT and Write Multiple FUA
EXT commands supported
Bit 5: If set, General Purpose Logging Feature Set
supported
Bit 4: Obsolete
Bit 3: If set, Media Card Pass Through Command feature
set supported
Bit 2: If set, Media serial number is valid
Bit 1: If set, SMART Self-Test supported
Bit 0: If set, SMART Error Logging supported
88Ultra DMA modes
Bit 15: Reserved
Bit 14: If set, Ultra DMA Mode 6 is selected
Bit 13: If set, Ultra DMA Mode 5 is selected
Bit 12: If set, Ultra DMA Mode 4 is selected
Bit 11: If set, Ultra DMA Mode 3 is selected
Bit 10: If set, Ultra DMA Mode 2 is selected
Bit 9: If set, Ultra DMA Mode 1 is selected
Bit 8: If set, Ultra DMA Mode 0 is selected
Bit 7: Reserved
Bit 6: Ultra DMA mode 6 supported
Bit 5: Ultra DMA mode 5 supported
Bit 4: Ultra DMA mode 4 supported
Bit 3: Ultra DMA mode 3 supported
Bit 2: Ultra DMA mode 2 supported
Bit 1: Ultra DMA mode 1 supported
Bit 0: Ultra DMA mode 0 supported
89Bit 15-8: Reserved
Bit 7-0: Time required for Normal Erase mode SECURITY
ERASE UNIT command
90Bit 15-8: Reserved
Bit 7-0: Time required for Normal Erase mode SECURITY
ERASE UNIT command
100-103Total number of User Addressable Logical Sectors (QWord)WD40PURX (7,814,037,168)
104Streaming Transfer Time - PIO0
105Maximum number of 512 byte blocks per Data Set
Management command
106Physical sector size / logical sector size
Bit 15 Shall be cleared to zero
Bit 14 Shall be set to one
Bit 13 if set, Device has multiple logical sectors per physical sector.
Bit 12 if set, Device Logical Sector longer than 256 Words
Bits 11-4 Reserved
Bits 3-0 2X logical sectors per physical sector
107Inter-seek delay for ISO 7779 standard acoustic testing0
119Commands and feature sets supported (Continued from
120Commands and feature sets supported (Continued from
121-126Reserved0
127Obsolete0
128Security Status
129-159Vendor Specific0
160CFA power mode
161-167Reserved for the CompactFlash™ Association0
168Device Nominal Form Factor
169Data Set Management Command
170-173Additional Product Identifier0
174-175Reserved0
176-205Current Media Serial number0
words 82-84)
Bit 15: Cleared to zero
Bit 14: Shall be set to one
Bit 13-8: Reserved
Bit 7: If set, Extended Power Conditions feature set
supported
Bit 6: If set, Sense Data Reporting supported
Bit 5: If set, Free-fall Control feature set is supported
Bit 4: If set, DOWNLOAD MICROCODE with offsets is
supported
Bit 3: If set, READ and WRITE DMA EXT GPL optional
commands are supported
Bit 2: If set, WRITE UNCORRECTABLE EXT is supported
Bit 1: If set, Write-Read-Verify feature set is supported
Bit 0: Reserved for DDT
words 85-87)
Bit 15: Cleared to zero
Bit 14: Shall be set to one
Bit 13-8: Reserved
Bit 7: If set, Extended Power Conditions feature set
supported
Bit 6: If set, Sense Data Reporting supported
Bit 5: If set, Free-fall Control feature set is supported
Bit 4: If set, DOWNLOAD MICROCODE with offsets is
supported
Bit 3: If set, READ and WRITE DMA EXT GPL optional
commands are supported
Bit 2: If set, WRITE UNCORRECTABLE EXT is supported
Bit 1: If set, Write-Read-Verify feature set is supported
Bit 0: Reserved for DDT
0000 000X 001X XXX1b
Bit 15-9: Reserved
Bit 8: Security level (0 = High, 1 = Maximum)
Bit 7-6: Reserved
Bit 5: If set, Enhanced Security Erase supported
Bit 4: If set, Security count expired
Bit 3: If set, Security Frozen
Bit 2: If set, Security Locked
Bit 1: If set, Security enabled
Bit 0: If set, Security supported
Bit 15: Word 160 supported
Bit 14: Reserved
Bit 13: CFA power mode
Bit 12: CFA power mode 1 disable
Bit 11-0: Maximum current in ma
Bit 15-4: Reserved
Bit 3-0: Device Nominal Form Factor
Bit 15-1: Reserved
Bit 0: if set, the Trim bit in the Data Set Management
command supported
Bit 15-12: Vendor Specific
Bit 11-6: Reserved
Bit 5: If set, SCT Data tables command supported
Bit 4: If set, SCT Features Control command supported
Bit 3: If set, SCT Error Recovery Control command
supported
Bit 2: If set, SCT Write Same command supported
Bit 1: If set, Obsolete
Bit 0: If set, SCT Command Transport supported
207-208Reserved0
209Alignment of logical blocks within a physical block
Bit 15: Shall be cleared to zero
Bit 14: Shall be set to one
Bits 13-0: Logical sector offset within the first physical
sector where the first logical sector is placed.
210-211Write-Read-Verify Sector Count Mode 30
212-213Write-Read-Verify Sector Count Mode 20
214NV Cache Capabilities
Bit 15-12: NV Cache feature set version
Bit 11-8: NV Cache Power Mode feature set version
Bit 7-5: Reserved
Bit 4: If set, NV Cache feature set enable
Bit 3-2: Reserved
Bit 1: If set, NV Cache Power Mode feature set enable
Bit 0: if set, NV Cache Power Mode feature set supported
215-216NV Cache Size in Logical Blocks0
217Nominal media rotation rate1518h
218Reserved0
219NV Cache Options
Bit 15-8: Reserved
Bit 7-0: Device Estimate Time to spin up in seconds
220Bit 15-8: Reserved
Bit 7-0: Write-Read-Verify feature set current mode
221Reserved0
222Transport major version number
0000h or FFFFh=device does not report version
Bit 12-15: Transport Type (0h=Parallel 1h=Serial 2hFh=Reserved)
Bit 6-11: Reserved (Parallel, Serial)
Bit 5: Reserved SATA Rev. 3.0
Bit 4: Reserved SATA Rev. 2.6
Bit 3: Reserved SATA Rev. 2.5
Bit 2: Reserved SATA II: Extensions
Bit 1: ATA/ATAPI-7 SATA 1.0a
Bit 0: ATA8-APT ATA8-AST
223Transport minor version number0
224-229Reserved0
230-233Extended Number of User Addressable Sectors (Qword)0
234Minimum number of 512-byte data blocks per DOWNLOAD
MICROCODE command for mode 03h
235Maximum number of 512-byte data blocks per DOWNLOAD
WD Purple PR1334M Installation and Setup Procedures
5.0INSTALLATION AND SETUP PROCEDURES
Hard drives are precision instruments that must be handled with care to prevent damage. It is
important to understand that drives are typically damaged because of Electrostatic Discharge (ESD), rough handling, or shock and vibration. Refer to the WD 3.5-inch Hard Drive Han-
dling poster (part number 2378-701046) for details on drive handling.
Refer to http://support.wd.com/warranty for detailed instructions on all phases of repackaging the
drive.
Important: If your system does not support hot plugging (see “Hot Plug Support” on page 21), it
must be turned off and unplugged before installing your hard drive.
5.1Unpacking
5.1.1Handling Precautions
WD products are designed to withstand normal handling during unpacking and
installation. Take care to avoid excessive mechanical shock or electrostatic discharge
(ESD), which can permanently damage the hard drive and void the warranty. Hard
drives are typically damaged because of ESD, rough handling, or shock and vibration.
To avoid ESD problems, wear a properly grounded wrist strap when handling the
hard drive. Articles of clothing generate static electricity. Do not allow clothing to
come in direct contact with the hard drive or circuit board components.
When the WD drive is not in its shipping container or installed in its proper host
enclosure, it must remain in the anti-static bag. To prevent damage, do not unpack
your WD drive until you are ready to install it.
5.1.2Inspection of Shipping Container
Carefully examine the container for obvious shipping damage, such as: holes, signs of
crushing, or stains. Notify the carrier and your WD representative if you observe any
shipment damage. Always move the shipping container in the upright position
indicated by the arrows on the container.
5.1.3Removal From Shipping Container
Remove the WD drive from the shipping container only for inspection or installation.
Carefully open the box. When removing the WD drive from the box, follow these
precautions:
nGrasp the drive by the sides only; avoid touching the circuit board components.
nGently place the drive on its anti-static bag on a clean, level, grounded work area.
nDo not stack drives or stand the WD drive on its edge.
CAUTION: When removing the drive from the shipping container, be careful not to drop it.
Dropping the drive can severely damage the head disk assembly or printed circuit board.
Installation and Setup ProceduresWD Purple PR1334M
5.1.4Removal From Static Shielding Bag
Before removing the drive from its static shielding bag:
nMake sure that your work station is properly grounded.
nWear a properly grounded wrist strap with good skin contact.
nAvoid contact with any component on the printed circuit board.
After attaching your wrist strap, gently remove the drive from the static shielding
bag.
nHandle the drive by the sides only; avoid touching the printed circuit board.
nDo not open the drives sealed compartment or remove the seals or any labels
from the drive; this will void the warranty.
5.1.5Moving Precautions
If you need to move your computer, turn off the power to automatically unload the
heads. This helps protect the media and the heads from accidental damage due to
vibration, moving, or shipping.
5.2Mounting
Use either the four bottom screws or at least four of the side mounting screws to
rigidly support the drive and prevent vibration. Some adapter frames may not have
the mechanical design structure capable of mounting the drive to meet the specified
shock and vibration requirements.
The hard drive itself does not provide electrical isolation between mounting locations
and drive ground connection. If electrical isolation is required, the system designer or
integrator would be responsible for providing a solution.
5.2.1Mounting Restrictions
If your system does not support hot plugging (see “Hot Plug Support” on page 21), it
must be turned off and unplugged before installing your hard drive.
5.2.2Orientation
You can mount the hard drive in the X, Y, or Z axis, depending upon the physical
design of your system. For best results, mount the drive with all four screws grounded
to the chassis. If all four screws are not used, see "Grounding" on page 40.
5.2.3Screw Size Limitations
The hard drive should be mounted to the chassis using four 6-32 screws.
Recommended screw torque is 5 in-lb. Maximum screw torque is 10 in-lb.
CAUTION: Screws that are too long can damage the hard drive. Hard drive screw
penetration can differ between products depending upon hard drive design.
WD’s minimum design criteria is to always meet the SFF 8301 industry standard
specification. The industry standard as defined in the SFF 8301 specifies a
maximum of 3 mm screw penetration, and for a minimum of 2.4 mm of thread
engagement from both the screw and the hard drive.
See Figure 2-1 for allowable fastener penetration for this product family.
5.2.4Grounding
The PCBA and HDA grounds are always connected together in the drive and cannot
be disconnected. The drive mounting screws, unless intentionally isolated, will
WD Purple PR1334M Installation and Setup Procedures
provide additional ground connections between the HDA and the system chassis. If
the drive isn't grounded via mounting screws as described under “Mounting” on
page 40, there may be increased electrical emissions (EMI).
5.3Hard Drive Installation
If your system does not support hot plugging (see “Hot Plug Support” on page 21), it
must be turned off and unplugged before installing your hard drive.
5.3.1Jumper Settings
It is not necessary to place a jumper shunt on the drive for workstation/desktop use.
For enterprise storage environments, the advanced settings are as follows:
SSC Mode – Spread spectrum clocking feature enabled or disabled (jumper on pins 1-
2). Default setting is disabled.
PUIS Enabled Mode – To designate the drive as power-up in standby (power
management 2 or PM2) enabled, place a jumper on pins 3-4 (default setting is
disabled). This mode enables controlled spinup via spinup command per ATA
standard. It is mainly used for server/workstation environments operating in multiple
drive configurations.
Important: PUIS mode requires a compatible BIOS that supports this feature. If PUIS is enabled
and not supported by BIOS, the drive will not spin up and therefore will not be detected by the
system.
Native Gen2 Enabled Mode – To revert to the SATA 3 Gb/s data transfer speed, place a
jumper on pins 5-6.
Force Gen1 Enabled Mode – To revert to the SATA 1.5 Gb/s data transfer speed, place
jumpers on pins 5-6 and 7-8.
WD Purple PR1334M Installation and Setup Procedures
5.3.2Attach the Power Supply Cable
If your system does not support hot plugging (see “Hot Plug Support” on page 21), it
must be turned off and unplugged before installing your hard drive. This avoids the
possibility of reversing the polarity of the power connections and eliminating current
surges that can damage either the drive or computer.
Attach the SATA power supply cable to the SATA device plug power connector. The
SATA power connector is keyed to ensure proper insertion.
Figure 13. Connector Locations
5.3.3Attach SATA Interface Cable
You can configure the hard drive two ways:
1.Cable the drive directly to a SATA connector on the motherboard, or
2.Cable the drive to a host adapter card mounted in one of the expansion slots in the computer.
Both configurations use a SATA interface cable.
Make sure the SATA interface cable is no longer than 1 meter (39.37 inches) to
minimize noise that is induced on the data and control buses.
Figure 14. SATA Interface Cable
5.4Serial ATA Latching Connector
This hard drive also allows Serial ATA latching cable connections. The latching
connector provides a secure connection between the drive and the cable connector
via a locking latch mechanism. The new latching connector design has two channels,
one above the power connection and one above the data connection. Latch
alignment with these channels forms an interlock when the latching cable is inserted
into the drive. This latching feature makes the SATA connector more robust and
ensures a click-lock connection which is verifiable even in noisy environments.
The hard drive requires no preventative maintenance and contains no user-serviceable parts.
The service and repair of drives can only be performed at a WD Service Center. Please contact your WD representative for warranty information and service/return procedures.
Observe the following precautions to prolong the life of the drive:
nDo not attempt to open the sealed compartment of the drive as this will void the war-
ranty.
nDo not lift a drive by the printed circuit board.
nAvoid static discharge when handling a drive.
nAvoid harsh shocks or vibrations.
nDo not touch the components on the printed circuit board.
nObserve the environmental limits specified for this product.
nIf it becomes necessary to move your computer system, turn off the power to automati-
cally unload the heads. This helps protect the media and the heads from accidental damage due to vibration while moving or shipping.
nTo protect your data, back it up regularly. WD assumes no responsibility for loss of data.
For information about back-up and restore procedures, consult your operating system
manual. There are also a number of utility programs available that you can use to back up
your data.
Active LED Status — The WD drive supports external LED requirements. It provides an activity LED
output which is ON during command execution and OFF otherwise.
Annualized Failure Rate (AFR) — A method of measuring failure rates or trends for a group of
units at a site. The rates are based on the monthly total number of returned field failure units
divided by the total cumulative installed base and multiplied by 12 (to annualize the failure
rate).
Advanced Format (AF) — Technology adopted by WD and other drive manufacturers as one
of multiple ways to continue growing hard drive capacities. AF is a more efficient media format that enables increased areal densities.
AllFrame 4K — AllFrame 4K™ technology improves ATA streaming to help reduce frame loss,
improve overall video playback, and increase the number of hard drive bays supported within
a NVR.
Automatic Defect Retirement — If defective sectors are found during a read or write, they
are automatically mapped out and relocated.
Block — A group of bytes handled, stored, and accessed as a logical data unit.
Buffer — A temporary data storage area that compensates for a difference in data transfer
rates and/or data processing rates between sender and receiver.
Command Queuing — See Native Command Queuing (NCQ)
Data Lifeguard™ — Representing WD's ongoing commitment to data protection, Data Life-
guard data protection utilities include thermal management, an environmental protection
system, and embedded error detection and repair features that automatically detect, isolate,
and repair problem areas that may develop over the extended use of the hard drive.
Data Transfer Rate — The rate that digital data is transferred from one point to another,
expressed in bits per second or bytes per second.
Defect Management — A general methodology of eliminating data errors on a recording surface by mapping out known bad areas of the media.
Dual Stage Actuator Technology — A head positioning system with dual-stage actuators that
improves positioning accuracy over the data track(s). The primary stage provides course displacement; the secondary stage uses piezo electric motion to fine tune the head positioning
to a higher degree of precision.
Dynamic Fly Height Control — This feature is designed to compensate for head/media separation changes due to temperature and altitude. It adds margins across temperature and altitude changes.
Error Correction Code (ECC) — A mathematical algorithm that can detect and correct errors
in a data field by adding check bits to the original data.
F.I.T. (Functional Integrity Testing) — A suite of tests WD performs on all its drive products
to ensure compatibility with different hosts, operating systems, application programs, and
peripherals. This testing must be performed before the product can be released to manufacturing.
Fluid Dynamic Bearings (FDB) — Bearing design that incorporates a layer of high-viscosity
lubricant instead of ball bearings in the hard drive spindle motor. FDB designs provide
increased non-operational shock resistance, speed control, and improved acoustics.
Formatted Capacity — The actual capacity available to store data in a mass storage device.
The formatted capacity is the gross capacity minus the capacity taken up by the overhead
data required for formatting the media.
Hot Plugging — The ability to swap out a failed hard drive without having to power down the
system or reboot.
Latency — The period of time that the read/write heads wait for the disk to rotate the data
to an accessible position. For a disk rotating at 10,000 RPM, the average latency is 3 milliseconds.
IntelliSeek — WD technology that proactively calculates an optimum seek speed to eliminate hasty movement
of the actuator that produces noise and requires power.
Logical Block Address — An alternative addressing methodology of identifying a given location on a SATA drive that permits disk sizes greater than 528 MB.
Native Command Queuing (NCQ ) — NCQ allows the drive to re-order read commands, thereby
increasing random read IOPs. NCQ is a true Enterprise feature for environments such as database,
Web servers, and e-mail servers.
NoTouch™ Ramp Load Technology — The recording head never touches the disk media ensuring
significantly less wear to the recording head and media as well as better drive protection in
transit.
Preemptive Wear Leveling (PWL) — WD feature that provides a solution for protecting the
recording media against mechanical wear.
PRML (Partial Response Maximum Likelihood) — A read channel using sampled data, active
equalization and Veterbi detection to accurately retrieve the user data off the disk.
RoHS (Restriction of Hazardous Substances) — WD hard drive products manufactured and sold
worldwide after June 8, 2011, meet or exceed Restriction of Hazardous Substances (RoHS) compliance requirements as mandated by the RoHS Directive 2011/65/EU.
Rotational Latency — The amount of delay in obtaining information from a disk drive that can
be attributed to the rotation of the disk. For a disk rotating at 10,000 RPM, the average
latency is 3 milliseconds.
RPM (Revolutions per Minute) — Rotational speed of the media (disk), also known as the spindle speed. Hard drives spin at one constant speed. The slower the RPM, the higher the
mechanical latencies. Disk RPM is a critical component of hard drive performance because it
directly impacts the rotational latency and the disk transfer rate.
Seek Time — The time it takes for the read/write head to move to a specific block of data on
the hard drive. The average seek time is computed by dividing the time it takes to complete
a large number of random seeks by the number of seeks performed.
Data Sector — A 512-byte packet of data.
Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.) — A technology to assist
the user in preventing possible system down time due to hard drive failure.
Serial ATA (SATA) — SATA is the industry standard bus interface for hard drives. It is designed
to replace Parallel ATA, and has many advantages including increased transfer rate, improved
signal integrity, enhanced data protection, and hot plugging.
S.M.A.R.T. Command Transport (SCT) — The SCT Command Transport feature set provides a
method for a host to send commands and data to a device and for a device to send data and
status to a host using log pages.
Staggered Spinup — SATA feature that allows the system to control whether the drive will
spin up immediately or wait until the interface is fully ready.
Unrecoverable Error — A read error that cannot be overcome by an ECC scheme or by
rereading the data when host retries are enabled.
World Wide Name (WWN) — The World Wide Name (WWN) defined in ATA/ATAPI-7 is a
modification of the IEEE extended unique identifier 64 bit standard (EUI-64) and is comprised
of three major components: naming authority, organizationally unique identifier (OUI) and
serial number. WD's OUI is 0014EEh.
Write Cache — A feature in CacheFlow that posts “command complete” prior to completing
the actual write.