Android and Windows are separate worlds, right? Not according to BlueStacks. The Campbell, Calif.-based company has released a beta of its App Player for PC, which uses patent-pending technology to allow Android apps to run on XP, Vista and Windows 7 PCs.

The patent-pending technology is called LayerCake, an appropriate label since Google has named versions of Android after desserts, such as Ice Cream Sandwich or Cupcake. It enables Android apps designed for ARM processors to run on PC x86 hardware, and to use hardware graphics acceleration.

'Disruptive Technology'

With the BlueStacks app, Android software written for smartphones and tablets can run full-screen on Windows machines. Smartphone features, such as pinch-to-zoom and accelerator-tracked tilting, can be used on the PC through the mouse and keyboard arrows. Users of BlueStacks on a PC can download Android apps directly, even if they don't own an Android device.

In its announcement, BlueStacks quoted AMD corporate vice president Manju Hegde, who called LayerCake "a disruptive technology" that leverages "the advanced graphics capabilities of AMD APU and GPU platforms."

BlueStacks' investors include AMD as well as Citrix Systems, Andreessen Horowitz, Ignition Ventures and others.

This beta follows an alpha test of a more limited version of the software that ended late last year. In the three months of its release, the alpha attracted more than a million users in over 100 countries, running more than 4 million Android apps.

BlueStacks CEO Rosen Sharma noted that the porting of the Angry Birds game to Chrome was considered "a big deal," as was Microsoft CEO Steve Ballmer's announcement at a trade show that "Cut the Rope had been ported to IE9." But with BlueStacks, he said, "it's 450,000 apps coming to Windows at once."

Supports 'Mobile First'

The makers of several leading Android apps are allowing their software to be pre-loaded into the beta version. The apps include Barnes & Noble's Nook, Townsmen, Evernote, Defender, StumbleUpon, Fruit Ninja, and SliceIt! One developer, HandyGames, said in a statement that its apps run without modification.

The app player also includes Cloud Connect, an online service that allows PCs to function as extensions of smartphones, such as sending a SMS to a PC.

Jeffrey Hammond, an analyst with industry research firm Forrester, said the BlueStacks app particularly "meets the needs of those developers who are moving toward a mobile-first" development path, where they first target tablets and smartphones, followed by laptops and desktops.

At the moment, he said, many of those developers are focusing first on iPad, but he predicted it would soon become more commonplace for Android devices to be targeted first.

Hammond pointed out that Research In Motion is similarly "embracing Android," so that Android apps can run on its mobile devices. He said he would be "shocked" to see the same technology available for Apple's iOS devices, although, "theoretically," iOS apps could be made to run on PCs.