You may know that I do all my work using MacBook Pro. Like other notebooks, the MacBook goes into sleep mode when you close the lid/display or tap the power button and choose the Sleep option. Apple likes to make things seamless for its users - this is the main reason I switched from Windows as my day-to-day operating system (I use Windows for all of my other work, but the split between the time in Windows versus using MacOS directly is actually about 50/50!).

Apple setup Sleep such that the computer can run out of battery power when it is in Sleep mode and still be able to recover. It does this by writing the contents of RAM into a file before it goes into Sleep mode. The MacBook Pro is a fast computer, so it takes about 10 seconds to write out the contents of RAM to a file.

While this is a nice feature, the 4Gb of disk space this uses comes in handy, especially since I have a few virtual machine images ranging between 5 and 60 Gb - I can use all the disk space I have.

SmartSleep is an application that allows you to set the Sleep mode such that the Mac does not write the contents of RAM to a file before going to sleep - saving time and disk space. SmartSleep also provides a Sleep mode called SmartSleep that lets you set a number (interpreted as percent of charge left or run time on battery remaining) - once the batter hits this value, SmartSleep writes the contents of RAM out to a file to avoid loss of data! Cool.

Granted, you have to be careful about using SmartSleep in SmartSleep mode since it's possible that you MacBook can run out of battery power when it's in a nicely padded laptop bag, or being bounced around in the trunk of your car - but this is a small consideration when you think of the amount of time and disk space you'll save each time you put your MacBook to sleep (in my case, I restart my MacBook every few months, so this is really handy).