One of the "under the hood" improvements that Apple might be planning for Mac OS X Snow Leopard might involve a crash diet for key Mac applications.
Roughly Drafted reports, in a long list of features expected to appear in Snow Leopard, that Apple is working on reducing the footprint required by many of its key applications, such as iCal, Mail, and Preview. The report also says the size of the Utilities applications could be dramatically reduced, from 468MB to 111.6MB.
Smaller applications could make Snow Leopard more snappy and more stable, as Apple prunes out unnecessary code and features. This would also make Snow Leopard more friendly for computers with solid-state drives, like the one found in the MacBook Air, Roughly Drafted suggests.
Snow Leopard is expected next year, and 64GB flash memory drives like those found in the MacBook Air will be still very expensive at that point. And flash drives north of 100GB, as most hard drives are these days, are out of reach for just about everyone.
This could also make Mac OS more mobile-friendly. Apple's operating system development is headed down two paths at the moment, for the Mac and the iPhone. However, we know OS X iPhone and OS X Leopard have an awful lot in common, and if Snow Leopard has a smaller footprint it could extend battery life in a mobile device.
Apple discussed Snow Leopard in front of its developers two weeks ago at the Worldwide Developers Conference, but hasn't said all that much about the next operating system in public. The company has said it plans to focus on improving the internal structure of the operating system rather than focusing on new features, specifically revealing plans to improve support for multicore processors and graphics chips.