Windows 8 strives for optimal battery life

Windows 8 is stingy doling out power to applications, particularly what Microsoft calls Metro-style applications written exactly for the operating system, all in an effort to prolong battery life.

According to the latest Building Windows 8 blog power efficiency is a priority feature in other words designed into the operating system however also supported in Metro-style applications via a set of APIs that allow background application activity without draining battery reserves.

The operating system itself

Power scrimping extends to the operating system itself, the company says, an effort it calls power hygiene. The goal is to balance this economy with functionality, so, for instance, applications finish tasks they have started even if users switch to something else.

Suspended apps do consume memory, nevertheless, and Windows 8 can shut down apps if system memory starts to run low. When that happens, apps that haven't been used recently are shut down. The system saves the state of the shut-down app so when it is switched to, it opens to the same point it was at previously it shut down. The user experience should be very similar to what it would be if the app had not been shut down, the blog says.

This requires developers of Metro apps to write to the background API to take advantage of the power savings. Traditional desktop apps run on Windows 8 nevertheless sap battery life the same way they do now. They are playing music, downloading/uploading files to Web sites, refreshing live tiles with content, printing, receiving VoIP (Voice over Internet Protocol) calls, instant messages and emails, sharing content and synching with tethered devices.

"Nevertheless over time, we're equipping Windows to get more done and use less power, with new applications that help you get that work done - from entertainment to professional tools and everything in between," the blog says.

For Metro apps, Windows 8 as well includes a feature called Desktop Activity Moderator in other words the mechanism for putting the apps into standby so they don't drain battery life.