Does Mac OS X support hibernation?
Is it possible to hibernate a Mac? And if so is it safe to remove the power from the computer when it is hibernated?
Apple prefers using a power-efficient sleep state rather than hibernating.
When you close the lid of an Apple laptop, press the power button and choose Sleep, or use "Sleep" from the Apple menu, it enters a sleep state that is very power efficient. I can leave my laptop in sleep mode for days without losing a significant amount of battery. It also turns back on ready to work in about 1 second.
Macs newer than about October 2005 use Safe Sleep, which saves data stored in RAM to the hard disk as well. This is what happens when you hibernate a PC. If your computer loses power while it is sleeping, it will restore RAM contents from disk.