Hitachi 100GB 7200 RPM HTE721010G9SA00 Benutzerhandbuch

Travelstar E7K100 (Serial ATA) Hard Disk Drive Specification

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ing of the heads is invoked by the commands: 

UL = unload

Comp. = complete

Load/unload is also invoked as one of the idle modes of the drive. 

The specified start/stop life of the product assumes that load/unload is operated normally, NOT in emergency mode.

When HDD power is interrupted while the heads are still loaded, the microcode cannot operate and the normal 5V 
power is unavailable to unload the heads. In this case, normal unload is not possible, so the heads are unloaded by 
routing the back-EMF of the spinning motor to the voice coil. The actuator velocity is greater than the normal case, 
and the unload process is inherently less controllable without a normal seek current profile. 

Emergency unload is intended to be invoked in rare situations. Because this operation is inherently uncontrolled, it 
is more mechanically stressful than a normal unload. 

A single emergency unload operation is more stressful than 100 normal unloads. Use of emergency unload reduces 
the start/stop life of the HDD at a rate at least 100X faster than that of normal unload, and may damage the HDD.

Problems can occur on most HDDs when power is removed at an arbitrary time. For example:

•

Data loss from the write buffer

•

If the drive is writing a sector, a partially written sector with an incorrect ECC block results. The sector 
contents are destroyed and reading that sector results in a hard error. 

•

Heads possibly land in the data zone instead of the landing zone, depending on the design of the HDD. 

You may then turn off the HDD in the following order:

•

Issue Standby Immediate or sleep command.

•

Wait until COMMAND COMPLETE STATUS is returned. (It may take up to 350ms in typical case).

•

Terminate power to HDD.

This power-down sequence should be followed for entry into any system power-down state, or system suspend 
state, or system hibernation state. In a robustly designed system, emergency unload is limited to rare scenarios such 
as battery removal during operation.

All addressing of data sectors recorded on the device's media is by a logical sector address. The logical CHS address 
for HTE7210XXG9SA00 is different from the actual physical CHS location of the data sector on the disk media. 

HTE7210XXG9SA00 support both Logical CHS Addressing Mode and LBA Addressing Mode as the sector 
addressing mode. 

Command

Response

Standby

UL -> Comp.

Standby immediate

UL -> Comp.

Sleep

UL -> Comp.