The PowerBook (FireWire) supports hibernation. Hibernation is activated when you select "Preserve memory contents on sleep." in the Energy Saver control panel shown in Figure 1. In this mode, the computer saves the entire contents of RAM to an invisible file on the hard disk before going to sleep. When the computer comes out of sleep, the file is read back into RAM. If for some reason the computer loses power and shuts off, it can still start up to the exact state it was in before sleeping and not lose any data stored in RAM.
Hibernation requires that Virtual Memory be turned on.
When you press the Power key, the computer starts up and automatically reloads the RAM contents from the hard disk.
The computer goes through a process similar to a normal startup, but it does not display the startup screen or the extension icons; instead, it displays a progress bar. After it restores the prior state, the computer resumes execution of whatever application was executing at the time the power was lost.
Figure 1 Energy Saver Control Panel
Additional Features of Energy Saver Control Panel
Wake options
Wake when the modem detects a ring - If the internal modem is connected and this option is selected, then the PowerBook awakens. This allows any software which needs to answer the call (such as fax software) to answer the call.
Wake when the computer is opened - This awakens the PowerBook whenever the lid is opened. Combined with preserve memory contents on sleep, this option provides instant access to applications whenever needed.
Other Options
Reconnect to servers on wakeup - When selected, the PowerBook tries to connect to any AppleShare servers that you were logged into before going into sleep. With just this option selected, and not remember my passwords, you are prompted to reenter your password for all the servers being remounted. This option can also cause the PowerBook to take longer to come out of sleep since it is remounting all the servers.
Remember my passwords - This option when selected allows the servers to be remounted without requiring you to reenter the password for the server.
Allow processor cycling - When selected, this option causes the PowerPC processor to go into low power mode after a few seconds of computer inactivity . When the processor goes into low power mode, it runs at 20 percent of normal speed, saving power.