K6610007
Rev.5
02.14.’03 - 17 -
3.4 Load/Unload Specifications
Load /Unload is a mechanism to load/unload the heads on the disk surfaces.
3.4.1 Normal Load/Unload
Normal load/unload operations are limited to maximum 300,000 times during HDD life. The normal unload
operation is performed by the following commands.
-
Standby
-
Standby Immediate
-
Sleep
Also, the normal unload is automatically performed by control software, during Idle mode. The above normal
unload time does not include an emergency unload as explained in Sec. 3.4.2.
3.4.2 Emergency Unload
The emergency unload is occurred by unexpected power down, and is limited to maximum 20,000 times
during HDD life. Since normal unload can not be performed by the software control after power off, the
heads are unloaded by a hardware control. The maximum number of emergency unload is defined
separately.
3.4.3 Required Power Off Sequence
To operate the load/unload normally, the following BIOS sequence is required by Host system before power
off.
[Sequence #1]: Execute one of following commands.
-
Standby
-
Standby Immediate
-
Sleep
Note:
Such as Soft Reset, Flush Cache command or Check Power Mode command does not
unload the heads.
[Sequence #2]: Check the Status Register, and wait the command complete.
Note:
The head is unload by the sequence #1 command, and the command completion
normally takes about 1sec. Considering the error retries, BIOS timer should be set to
over 30 sec by the Host side.
[Sequence #3]: Power off the drive
Above sequence is required for the Host system at Power off, Suspend and Hibernation operations.
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