Apple has released updates for the MacBook Air preparing the ultraportable for the new Power Nap feature of Mountain Lion, with the promise of a MacBook Pro Retina update in the pipeline. The System Management Controller (SMC) updates tweak the mid-2011 and 2012 MacBook Airs to support the new functionality, which allows them to silently power on while not in use and update software, check for new mail, synchronize media and make Time Machine backups, among other things.
Power Nap also supports calendar and contacts synchronization, along with reminders and notes, and makes sure your Mac has the latest content from your Documents in the Cloud account. It will also grab updates for your Mac App Store apps. If you've lost your notebook, you can use Find My Mac to locate it even if it's sleeping.
Not all of the functionality is enabled every time your Mac is sleeping, however. Only when there's a mains connection will Power Nap download software updates, makes Time Machine backups, run through Spotlight indexing, complete Mac App Store downloads and update Help Center.
Unfortunately, the 2010 MacBook Air isn't supported by Power Nap, and neither are any MacBook Pro models beyond the Retina Display toting model from this year. That's apparently due to a flash memory issue. The
More on Power Nap - and OS X 10.8 in general - in our full Mountain Lion review.