Andrew Escobar writes about the new SafeSleep mode on the PowerBooks (and possibly the whole Mac line-up). Apple talks about SafeSleep in a docs article and shows a sample photo of a waking PB G4. 
To make a long story short, there is a software based SafeSleep mode, somewhat like hibernate on Windows that is now possible. Your PowerBook will (when enabled) write out it’s state to a swapfile, making battery changes possible without shutting down a 12″ G4 PB. Yippie!
So far I’ve tested this successfully on a:
- 17″ iMac (1GHz USB1.0)
- 12″ PowerBook G4 (1.5 GHz)
- Power Mac G5 Dual 1.8 GHz (Q77)
I have access to an older 12″ PB G4 with the 867 MHz processor, but I haven’t had a chance to try it there yet.
NB: If you have the security features enabled that require you to unlock the screen when waking from sleep, you will not see the ‘greyscale blurred’ effect that the articles describe; your restoration will be on a black screen.
