Hibernate on OSX

As on Tiger, we have already had the hibernate functionality. Apple call it "Safe Sleep". Some people might use "Deep Sleep" for it.

Safe Sleep is to use /var/vm/sleepimage for saving data in the RAM to disk (by default). And once you lost your power of Mac, Tiger will read the sleepimage and restore your working stage. But in Energy Saver, there's no option about this Safe Sleep functionality. Many people said that you can input root#pmset hibernatemode 3/0  to switch safe sleep on/off. What if I want to safe sleep then power off ( just like Linux and MS' system doing ) ? The answer is unclear. Until....

I saw the article about new options of Leopard's Hibernate and a "Hibernate Bear".

Now I understand, the Evil Apple just hide the power manager's functions again.

So, if you aren't interested in HOW TO CUSTOMIZE YOUR SLEEP MODE. Just try the Bear above first. The bear support 3 sleep modes. That may satisfy your need.

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For further tuning about energy saving, I tried to man pmset. 

It said that 

• hibernate mode=0: This mode is to perform normal sleep. NOT safe sleep.
  
• hibernate mode=1: This mode is to save data to sleepimage then shutdown.
• hibernate mode=2: This mode is a SMART one. It will perform normal sleep when the battery is full. And when battery level is under "Hibernate Free Ratio"( Integer percentage ),  it will change to perform safe sleep. 
• hibernate mode=3: This mode is to save data to sleepimage then sleep. If you lost power supply, OS X will use sleepimage to recover working state.

Because I use Macbook pro, and the energy saving is important for a notebook. So, I tuned as follows.pmset -b hibernatemode 2 hibernatefreeratio 5 

pmset -c hibernatemode 0