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Sleeping on the edge

Sleeping on the edge

I’ve decided to disable the “Safe Sleep” option on Mallory (my MacBook Pro). Safe Sleep is the newish feature on mac laptops that suspends the contents of RAM to the hard disk so that it can recover if the battery is removed during sleep. While this is great for swapping batteries on a flight, I only have one battery at the moment. I think I’ve made use of the feature all of twice, and I wouldn’t have done that other than to test it out or simply be lazy because I knew I could.

On the other hand, I’m annoyed by it every single day. Not only can it potentially be a security risk, but it can sometimes take a very long time to write 2 GB to disk. Especially when you realize that you are about to miss your bus. And you know what isn’t a good idea? Grabbing your computer and running with it when the disk is busy. I have my computer set to automatically go to sleep when running off of battery power (though not when plugged in) so I think it would be far more likely that my desktop machine would die in it’s sleep due to a power outage than my laptop.

So the solution turns out to be easy. Detailed (and overly cautious) instructions are at Macworld.

In short, simply open up a terminal window and first verify what your current sleep mode setting is, then change it to 0, plain vanilla sleep. The command pmset -g or, to zero in on the sleep setting, pmset -g | grep hibernatemode will take care of the first order of business. To change the mode, type:

sudo pmset -a hibernatemode 0

That’s it. Apparently the system may reset to the default if you open up the Energy Saver preferences, so if you see it going back to default behavior just repeat the above steps. And if you are going on a trip and think you might be swapping batteries you can always change the setting back (usually 3 — 7 if use secure virtual memory — but you should check what your setting is and remember it). Also there’s a Dashboard widget linked to in the Macworld article to automate the process of putting your computer directly into hibernation then resetting things back to normal when it wakes.

By the way, another place where Safe Sleep can save your ass is when you are having battery problems and your power cuts out before you think it will. However this only works if it actually cuts out while the computer is asleep. Usually the computer won’t even have time to sleep. And, please, if you are experiencing battery problems take your battery in to be replaced immediately. Malfunctioning batteries can be a very bad thing.

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