Microsoft Corp. has finally revealed official details about Windows 8 operating system for ARM-based system-on-chips (SoCs). The software giant clearly wants end-users to have fully-fledged Windows experience on devices - primarily tablets at first - running ARM chips, but at the same time imposes restrictions that substantially limit third-party applications on Windows-on-ARM (WOA) platform.

"Using WOA 'out of the box' will feel just like using Windows 8 on x86/64. 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," wrote Steven Sinofsky, the president of the Windows division at Microsoft, in a blog post dedicated to the new Windows platform.

Windows on ARM can support all new Metro style apps, including apps from Microsoft for mail, calendaring, contacts, photos, and storage. WOA also includes support for hardware-accelerated HTML5 with Internet Explorer 10. WOA also includes desktop versions of the new "Office 15" Microsoft Word, Excel, PowerPoint, and OneNote, the applications which have  have been significantly architected for both touch and minimized power/resource consumption, while also being fully-featured for consumers and providing complete document compatibility. Moreover, WOA fully supports the Windows desktop experience, File Explorer, Internet Explorer 10, Windows desktop features and so on.

But while end-users will get everything that Microsoft has to offer with WOA, all the other programs will need to be redesigned for both ARM chips as well as touchscreen interface. Generally, it means that none of today's Windows programs will run on Windows 8 on ARM platform. At the same time, Microsoft is glad to announce that Metro style apps in the Windows Store can support both WOA and Windows 8 on x86/64, but does not indicate that Metro style apps will hardly look good on large screens.

What is even more important is that WOA will not support any type of virtualization or emulation approach, and will not enable existing x86/64 applications to be ported or run since Microsoft believes that supporting various forms of emulation "runs counter to the goal of delivering a product that takes a modern approach to system reliability and predictability".

Even though Windows 8 on ARM will "feel" and "look" like fully-fledged Windows, it will clearly be a different platform and as so, Microsoft wants WOA PCs to be "clearly labeled and branded so as to avoid potential confusion with Windows 8 on x86/64". Still, since those systems will be considered as "Windows-based", many customers will inevitably expect compatibility with older apps and therefore a lot will be disappointed.

Tags: Microsoft, Windows, Windows 8, ARM