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G2244 G2244 is offline
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Question Sleep And Hibernate on Type11 Explained (for Newbs) - 01-29-2009, 02:37 PM

I am posting this separately so hopefully its gets put into the FAQ section.

Being new to OS X as I am, I was very confused about all the discussion relating to sleep, hibernate, and how they interact in OS X. This was posted in another thread by AlecEdworthy and did a great job of explaining it. I hope others find it useful as well. Feel free to correct or add on if anything isn't quite right.

Originally Posted by AlecEdworthy
...Normally a Mac laptop uses Safe Sleep where it writes the contents of the RAM to a hibernate file but also keeps the RAM powered (almost instant power on, with a pretty low power use but a slightly longer time to enter sleep mode). When the power drops below a certain level the Mac will momentarily power up and go into full hibernation mode (i.e. power down the RAM too) to make sure that when the power goes completely it can recover from the copy of the RAM in the hibernation file. If the power is lost before this happens (e.g. the battery on a laptop is removed) all is still OK as the hibernation file was written when the device first went to sleep.

You can disable Safe Sleep and delete the hibernation file and thus recover a large chunk of disk space (roughly equal to the amount of RAM you have, so 1Gb or 2Gb normally).

The Dell Mini 9 running the current Type11/bmaltais EFI does not support hibernate, it attempts to write the hibernation file, fails and so just enters sleep mode. Re-enabling Safe Sleep at a later date (e.g. when bmaltais fixes it, a feat I'm sure he'll achieve in the not too distant future ) is as simple as executing one command so it is safe to disable it now, recover the disk space and then re-enable it later on.

Regards, Alec

Former owner of... (sold through this site)
Dell Mini 9
Other Mods - 2Gb RAM, RunCore "64"Gb SSD, Dell Wireless 1505 b/g/n, Dell Bluetooth, US "Int'l" Keyboard
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