MBP and losing power

I was taking a look at a MBP today in CDW's warehouse business tech center, and accidentally unplugged it (that magnetic power cord is a nice thing, but it does unplug easily). The odd thing is that I could have sworn the battery wasn't in the unit (at least, there was a big gaping hole in the bottom of the unit), and yet when I replugged the power, I returned back to where I was when the system was unplugged.

My question is: does the MBP have some sort of bridge battery that retains RAM in the event of such a power loss? Or, was the battery still plugged in, and I was looking at the wrong hole?

 

Most notebooks have a small internal watch battery to keep the time and date, but I don't think this small battery would be able to sustain the notebook. Usually most notebooks store information, such as Word Documents, in the RAM banks and then re-access them once the notebook has been properly booted again and is running. However, I don't think that large files, such as TV recordings and your status in a game will be saved.

 

it prolly has the five minute ram back up battery that apple has put in the power books. its meant to maintain the ram in sleep for 5 min so you could change the battery without turning off the notebook.

 

That must be it... Nifty, I must admit. Unplug my 8204 without a battery, and it's good night work...