Microsoft Details Windows-On-ARM Development Efforts

ARM-based PCs running Windows should be available at the same time x86-based PCs ship with Windows 8, a Microsoft executive said in a blog post Thursday.

And the first Windows-based ARM test devices will be offered to developers when the "consumer preview" of Windows is released February 29, said Steven Sinofsky, president of the Windows and Windows Live Division, in the lengthy, 8,000-word blog.

Windows on ARM PCs, "are still under development and our collective goal is for PC makers to ship them the same time as PCs designed for Windows 8 on x86/64," Sinofsky said in the blog. "We created WOA [Windows on ARM] to enable a new class of PC with unique capabilities and form factors, supported by a new set of partners that expand the ecosystem of which Windows is part."

While Microsoft is working closely with Intel and Microsoft to develop Windows 8 for the x86/64 architecture, it also has partnerships with Nvidia Corp., Qualcomm and Texas Instruments to port Windows to the ARM-based microprocessors they manufacture.

Those ARM chips are increasingly popular for tablet computers and other mobile devices. Microsoft is counting on those partnerships to help it break into the tablet market that's now dominated by Apple's iPad and devices running the Google Android mobile operating system.

"Windows 8 on ARM (WOA) is separate but equal. It is a different OS on its own schedule, but Microsoft is doing its best to deliver it at the same time," said Al Hilwa, IDC program director of applications development software, in an e-mailed commentary on Sinofsky's blog post.

Sinofsky said "a limited number" of ARM-based PCs running Windows will be made available to developers and hardware partners "in a closed, invitation-only program" at the same time the Windows 8 consumer preview is made available. But he cautioned that these test devices "are not samples or hints of forthcoming PCs, but tools for hardware and software engineers running WOA-specific hardware.

Last September, at its Build conference, Microsoft provided some 5,000 attendees with "technical preview" releases of Windows 8 running on x86-based tablet devices.

Microsoft, Nvidia, Qualcomm and Texas Instruments have not disclosed details about the kinds of Windows-based ARM devices they or their manufacturing partners are developing. "We created WOA to enable a new class of PC with unique capabilities and form factors, supported by a new set of partners that expand the ecosystem of which Windows is part," Sinofsky said.

Next: Microsoft Promises Windows-On-ARM Will Support Metro-Style Apps Developed For Windows 8

Windows 8 will sport a new look-and-feel with its "Metro-style" user interface and Sinofsky disclosed that WOA would support the same Metro applications as Windows 8, including Microsoft mail, calendaring, contacts, photos and storage software. Metro-style applications sold through the Windows Store will support both WOA and Windows 8 on x86/64.

WOA "has a very high degree of commonality and very significant shared code with Windows 8," Sinofsky said.

"Using WOA 'out of the box' will feel just like using Windows 8 on x86/64," Sinofsky wrote. "You will sign in the same way. You will start and launch apps the same way. You will use the new Windows Store the same way. You will have access to the intrinsic capabilities of Windows, from the new Start screen and Metro style apps and Internet Explorer, to peripherals, and if you wish, the Windows desktop with tools like Windows File Explorer and desktop Internet Explorer. It will have the same fast and fluid experience. In other words, we’ve designed WOA to look and feel just like you would expect."

WOA will support the next release of Microsoft Office, code-named Office 15, and also will support "hardware-accelerated HTML5" with Internet Explorer 10.

"Windows 8 on ARM will not run old apps even if they are recompiled," Hilwa said in his commentary. "Microsoft will control both Metro-style and desktop apps for WOA through its app store and will require developers to rewrite existing apps to the new APIs for the desktop as well."

While the blog post focused on Microsoft's WOA development work with the ARM chip manufacturers, Sinfosky said Microsoft's Windows 8 development efforts for x86/64 processors has resulted in "a deeper level of collaboration with Intel and AMD on the full breadth of PC offerings than in any past release."

"We could not be more excited or supportive of the new products from Intel and AMD that will be part of Windows 8 – across a full spectrum of PC form factors including tablet, notebook, Ultrabook, all-in-one, desktop, and more that all take advantage of the new capabilities of Windows 8 while Windows 8 takes advantage of new features in hardware," Sinofsky said.