HGST low RPM.pdf

Power and Acoustic Management

Quietly Cool

Hitachi’s Deskstar drives can be conﬁ gured to reduce

audible noise and minimize power consumption—making

your organization a cooler, quieter place to work.

Deskstar drives have four stages of readiness and each

level offers power and cooling beneﬁ ts. Figure 1 shows the

percentage savings and recovery times associated with

each mode.

Here is a summary of how each mode can offer you

these valuable power savings, again referencing the

Deskstar 7K400.

Low power, high priority

Deskstar drives enable very desirable attributes for both

hard drives and the systems that use them. The Deskstars

can be conﬁ gured to reduce both audible noise and

reduce power demands. Whenever the system is located

near the user, low acoustics are important. Low noise

levels can also be important in audio/video production

environments.

Power savings are important in all applications.

Reducing drive power requirements beneﬁ ts the

system in several ways.

• Less cooling is required

• Less costly power supplies are needed

• Greater reliability for all components can be realized

The follow details describe Hitachi’s Deskstar 7K400,

5 platter model. Other Deskstar models also enable

reduced acoustics and power. Speciﬁ cations may vary

with each model.

Figure 1: Deskstar 7K400 (PATA) Power savings and recovery times

in four modes

Normal

In the normal ready mode, the drives respond immediately

to system requests for data. The Deskstar drives, in the

standard conﬁ guration, lead the industry for low power

requirements. This, leading low power enables lower cost

power supplies and less cooling than required for other ATA

drives. Deskstar drives achieve these integration beneﬁ ts

(lower power) while providing industry-leading performance.

Acoustics management

The Deskstar drives can be conﬁ gured to the silent seek

mode. When this mode is enabled, drive acoustics during

seeking drops from 3.5 bels to 3.3 bels. This improvement

not only makes for a quieter environment for the user,

there is also a power beneﬁ t. The drive’s power require-

ment drops signiﬁ cantly during seeking, from 13 watts

to 11 watts.

Unload

The heads can be sent to the ramp if the drive is idle for

several minute intervals. This mode reduces power, since

the servo circuit is disabled. 24% less power is required

than in the online mode. With a request for data, the drive

quickly returns to the online mode for rapid access.

Power management

PC system and other single-drive conﬁ gurations will realize

beneﬁ ts by utilizing the Deskstar power management

capabilities. The hard drive can be under utilized in many

single user applications. In these cases, the system can

switch the drive to one or more of the power saving modes

described below.

Low RPM

When longer periods of non use occur, additional power

savings is possible. In this mode, in addition to head

unload from the media, the spindle motor can be slowed to

a lower spin rate (approximately 60% of normal). This ac-

tion further reduces the power needed for the drive, 27%

less than the unload mode. In less than seven seconds,

the drive can be restored to ready mode for data access.

Power with control

In addition, ATA 3.5-inch drives are increasingly being

used in multi-drive conﬁ gurations. One typical application

is nearline storage, where the drives may remain idle for

extended periods. In such an environment, the Deskstar

drives’ multiple power modes can prove a real advantage.

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Power and Acoustic Management

Standby

One ﬁ nal mode enables the greatest power saving state.

In this case, as above, the heads are moved to the ramp.

In standby mode, power is removed from the disks. Stop-

ping the disks results in 38% savings over the Low RPM

mode, or a huge 87% less than when online.

The standby drive can be quickly brought to the online

mode, if for example, one of the active drives is removed

from the system. This mode is especially useful in RAID

environments where one drive serves as a spare.

Each of the four modes can be enabled via the Set Feature

commands. They are described in more detail in the

Advanced Power Management section of the Deskstar

Hard Disk Drive Speciﬁ cation.

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References in this publication to Hitachi Global Storage Technologies’ products, programs or services

do not imply that Hitachi Global Storage Technologies intends to make these available in all

countries in which it operates.

Product speciﬁ cations provided are sample speciﬁ cations and do not constitute a warranty. Informa-

tion is true as of the date of publication and is subject to change. Actual speciﬁ cations for unique

part numbers may vary. Please visit the Support section of our website, www.hitachigst.com/support,

for additional information on product speciﬁ cations. Photographs may show design models.

Hitachi Global Storage Technologies

3403 Yerba Buena Road

San Jose, CA 95135 USA

Produced in the United States 11/07.

Microdrive ® , Deskstar ® , Travelstar ® and Ultrastar ® are

registered trademarks of Hitachi Global Storage Technologies.

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