Fujitsu MHS2020AT, Product Manual

Page: 32 / 254

Device Overview
1-12 C141-E171-03EN
Emergency Unload other than Normal 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 Normal Unload cannot be executed.
Therefore, the number of Emergency other than Normal Unload is specified.
Remark:
This device is recommended to cut the power supply of HDD after head Unload
operates. We will inform of the power supply cutting sequence which this device
recommends as follows.
1) Disk Flush
Flush Cache command execution.
2) Head Unload
Standby Immediate command execution.
3) Wait Status
Please wait to complete the command by Status Register.
4) HDD power supply cutting
1.11Advanced Power Management
The disk drive shifts to the three kinds of APM modes automatically under the
Idle condition.
The APM mode can be chosen with a Sector Count register of the
SETFEATURES(EF) command.
The default mode of APM shifts to Low power idle(Mode-1).
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
SC = 80h - BFh : Mode-1 Low power Idle (Default)
SC = 01h - 7Fh : Mode-2 Standby
FR = 85h : Reset APM (return to Default.)