In the latest blog in Microsoft's excellent series on Windows 8 development, the company goes into detail on its new operating system's power management practices. There's an intense amount of detail, but Microsoft focused on the concept of "focus on the foreground" — Metro apps will act much like modern smartphone apps, with background apps using minimal resources based on a specific set of background capabilities. Microsoft goes on to outline the three possible states of apps: actively running in the foreground, suspended in the background, and performing a defined activity in the background.
While each scenario is fairly self-explanatory, Microsoft goes into detail on each one, outlining situations in which they occur and in which they might not behave as expected. For example, in some cases Windows 8 will remove an app from its suspended state and terminate it to free up memory for other active processes, a process that bears a lot of similarities to how OS X Lion uses automatic termination on apps to free up memory if necessary. There's also a full, detailed list of the available background processes for Metro-style apps as well as scenarios in which they might be used. It's clear Microsoft is taking power management seriously in Windows 8 Metro, and we think a big part of that is Office 15 for ARM, which we know the company wants to run properly and efficiently in desktop mode.