Fujitsu MPD3XXXAT Product Manual page 176

(1) Active mode
In this mode, all the electric circuit in the device are active or the device is under seek, read or
write operation.
A device enters the active mode under the following conditions:
Power-on sequence is completed.
A command other than power commands is issued.
Reset (hardware or software)
(2) Idle mode
In this mode, circuits on the device is set to power save mode.
The device enters the Idle mode under the following conditions:
After completion of power-on sequence.
After completion of the command execution other than SLEEP and STANDBY
commands.
Reset (hardware or software)
(3) Standby mode
In this mode, the VCM circuit is turned off and the spindle motor is stopped.
The device can receive commands through the interface. However if a command with disk
access is issued, response time to the command under the standby mode takes longer than the
active or Idle mode because the access to the disk medium cannot be made immediately.
The drive enters the standby mode under the following conditions:
A STANDBY or STANDBY IMMEDIATE command is issued in the active or idle mode.
When automatic power down sequence is enabled, the timer has elapsed.
A reset is issued in the sleep mode.
When one of following commands is issued, the command is executed normally and the
device is still stayed in the standby mode.
Reset (hardware or software)
STANDBY command
STANDBY IMMEDIATE command
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