FUJITSU MCM3064AP - Manual (Page 89)

4.4 Various Processes
C156-E227-01EN 4-19
4.4.7.1 Power mode
The ODD supports power modes shown below. The ODD uses a power mode
equivalent to standby mode, except that the DRDY bit is 0 while media is not
mounted.
• Active mode
• Pre-idle mode
• Idle mode
• Standby mode
• Sleep mode
4.4.7.2 Active mode
In active mode, all circuits are enabled. The ODD requires the shortest time to
start processing a command.
4.4.7.3 Pre-idle mode
In pre-idle mode, the read/write circuits stop. The ODD can receive a command
from the host, but since some circuits stop, the command requires 20 ms to access
media.
The ODD automatically enters pre-idle mode if no command is issued within a
specified time (0.5 second) in active mode. When it receives an access command,
the ODD automatically enters active mode. The pre-idle mode cannot be
controlled from the host computer.
4.4.7.4 Idle mode
In idle mode, the servo and read/write circuits stop. The ODD can receive a
command from the host, but because some circuits stop, the ODD takes 1 s
seconds (standard) to access media.
If no command is issued within a specified time (180 s) in active mode, the ODD
automatically enters pre-idle mode, then enters idle mode. When it receives an
access command, the ODD automatically returns active mode. The Idle
Immediate command can shift the ODD from active mode or standby mode to idle
mode.