Safe Sleep comes to OS X 10.4.3

A couple of years ago, I read something that detailed a new sleep feature coming to Mac OS X.  The idea was that when you put your PowerBook to sleep, the entire contents of RAM would be stored to an image on the hard drive as backup.  This way, if the battery died while the PowerBook was in sleep mode, once the power is restored the system could load the data from disk, restore it to RAM, and no data would be lost.

Now, admittedly, what I read so long ago offered little more info than I just explained.  Since that time, the feature has been notably absent… Until now.  With the release of OS X 10.4.3, and Apple’s latest update to the PowerBook line, it seems the feature had finally been introduced.

Apple calls this new feature Safe Sleep, and one day it will save your data.  The problem is that Apple has only enabled the feature on the latest line of PowerBooks.  Fear not, if you want to enable the feature on your system you still have a chance. has a great tutorial on how to enable the feature on other Mac systems.  Just be sure you are running 10.4.3 or later.

The tutorial details the changes that must be made via command line in OS X.  If you are intimidated by the command line, don’t worry.  Simply follow the instructions and simply copy and paste the commands from your browser into the terminal.  Be sure to reboot when instructed, and you will be all set.

Calling this a hack might be a little misleading.  While it is technically a hack, it is only enabling a feature that is currently built into the OS.  In fact, it seems only a matter of time before Apple allows older systems to use this feature without resorting to command line.  For now, give it a try.  I have a 1.25GHz PowerBook 15″, and this hacked worked brilliantly.  I even went to far as to put my machine to sleep and remove the battery for 30 min.  Then I put the battery back in and woke the machine up.  Sure enough, the machine picked right up where I left off.

Checkout Andrew Escobar’s tutorial at  It’s only a matter of time until this feature saves your data!


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