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Hi, i mailed fujitsu support asking about how the drive behaves with differents values of -B, because i didnt have a pattern.... after a few mails i got some technical info, a chapter un a PDF:
1.11 Advanced Power Management (APM)
Emergency Unload other than Unload is performed when the power is shut down
while the heads are still loaded on the disk.
The product supports the Emergency Unload a minimum of 20,000 times.
When the power is shut down, the controlled Unload cannot be executed.
Therefore, the number of Emergency other than Unload is specified.
1.10.1 Recommended power-off sequence
We recommend cutting the power supply of the HDD for this device after the
Head Unload operation completes. The recommended power supply cutting
sequence for this device is as follows:
1) Disk Flush
Flush Cache command execution.
2) Head Unload
Standby Immediate command execution.
3) Wait Status
Checking whether bit 7 of the status register was set to '0'.
(wait to complete STANDBY IMMEDIATE command)
4) HDD power supply cutting
The disk drive automatically shifts to the power saving mode according to the
setting of the APM mode under the idle condition.
The APM mode can be chosen with a Sector Count register of the SET
FEATURES (EF) command.
The disk drive complies with the three kinds of APM modes that a command from
the host is required.
FR = 05h : Enable APM
SC = C0h - FEh : Mode-0 Active Idle Low Power Idle
SC = 80h - BFh : Mode-1 Active Idle Low Power Idle (Default)
SC = 01h - 7Fh : Mode-2 Active Idle Low Power Idle Standby
FR = 85h : Disable APM (Set Mode-0)
The head is in a position of extreme inner in disk medium. (VCM Lock)
Low Power Idle:
The head is unloaded from disk. The spindle motor rotates.
Standby: The spindle motor stops.
In APM Mode-1, which is the APM default mode, the operation status shifts till it finally reaches "Low Power Idle."
Table 1.7 Advanced Power Management
APM Mode | Active Idle (VCM Lock) Low Power Idle (Unload) Standby (Spin Off)
Mode-0 0.2-1.2 sec 15 min. N/A
Mode-1 0.1-0.2 sec 10.0-27.5 sec N/A
Mode-2 0.1-0.2 sec 10.0-27.5 sec 10.0-40.0 sec
When the maximum time that the HDD is waiting for commands has been
Mode-0: Mode shifts from Active condition to Active Idle in 0.2-1.2, and to Low Power Idle in 15 minutes.
Mode-1: Mode shifts from Active condition to Active Idle in 0.1-0.2 seconds and to Low Power Idle in 10.0-27.5 seconds.
Mode-2: Mode shifts from Active condition to Active Idle in 0.1-0.2 seconds and to Low Power Idle in 10.0-27.5 seconds. After 10.0-40.0 seconds in Low Power Idle, the mode shifts to standby.
The default values of these settings are reflected in the WORD 91 values of the IDENTIFY DEVICE command. Also, the APM mode is initialized to Mode-1 (default value) at power-off.
The above mentioned is time until shifting to each power mode based on point that the drive becomes a command waiting state.
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anyone has an idea on how this is implemented on hdparm????