Strange loading screen when MBP battery dies and reboots

Question

I have a 2007 Macbook Pro and for nearly two years, the battery has been toast. In April, Apple replaced the logic board. Since the repair, whenever the power cable comes loose, the MBP shuts off as expected.

Before the repair, when the power cable was unplugged, the MBP simply shut off. Now, when I plug it back in and turn it on, it boots back up in the previous state, but has a white screen with loading bars at the bottom.

I haven't found anything related to this on the web. Is this related to the new logic board, or is there something else I should be concerned about? The MBP is running Leopard and is up to date.

Answer 1

This feature is called Safe Sleep. Apple notebooks will keep the RAM contents alive (sleep in PC jargon), but write a copy to the disk (hibernate, in PC jargon) at the same time.

If the battery runs out while the computer is sleeping, when it wakes up, it needs to read the RAM contents from disk, and thus you get the progress bar you are seeing.

Apple doc about it is here

Answer 2

This is so called "Hibernation" (my first met in windows). When battery dies, the OS dumps whole RAM into HDD (sort of swapping) so that no information is lost. When it's being booted back up, it loads the information back from HDD to RAM (hence you see the progress with those white bars).