As reported by Andrew Cunningham for Anandtech: Weve known that Microsoft has been planning an ARM-compatible version of Windows since well before we knew anything else about Windows 8, but the particulars have often been obscured both by unclear signals from Microsoft itself and subsequent coverage of those unclear signals by journalists. Steven Sinofsky has taken to the Building Windows blog today to clear up some of this ambiguity, and in doing so has drawn a clearer line between the version of Windows that will run on ARM, and the version of Windows that will run on x86 processors.
That’s right ARM cpus are in the news again this time info for the planned version of Windows 8 for the mobile CPU. And it is a separate version of Windows OS not unlike Windows CE or Windows Mobile or Windows Embedded. They are all called Windows, but are very different operating systems. The product will be called Windows on ARM (WOA) and is only just now being tested internally at Microsoft with a substantial development and release to developers still to be announced.
One upshot of this briefing from Sinofsky was the mobile-centric Metro interface will not be the only desktop available on WOA devices. You will also be able to use the traditional looking Windows desktop and not incur a big battery power performance hit. Which makes it a little more palatable to a wider range of users no doubt who might consider buying a phone or tablet or Ultrabook running an ARM cpu running the new Windows 8 OS. Along the same lines there will be a version of Office apps that will also run on WOA devices including the big three Word, Excel and Powerpoint. These versions will be optimized for mobile devices with touch interfaces which means you should buy the right version of Office for your device (if it doesn’t come pre-installed).
Lastly the optimization and linking to specially built Windows on ARM devices means you won’t be able to install the OS on just ‘any’ hardware you like. Similar to Windows Mobile, you will need to purchase a device designed for the OS and most likely with a version pre-installed from the factory. This isn’t like a desktop OS built to run on many combos of hardware with random devices installed, it’s going to be much more specific and refined than that. Microsoft wants to really constrain and coordinate the look and feel of the OS on many mobile devices so that an average person can expect it to work similarly and look similar no matter who the manufacturer of the device will be. One engineering choice that is going to assist with this goal is an attempt to address the variations in devices by using so-called “Class Drivers” to support the chipsets and interfaces in a WOA device. This is a less device specific way of support say a display panel, keyboard without having to know every detail. A WOA device will have to be designed and built to a spec provided by Microsoft for which then it will provide a generic ‘class driver’ for that keyboard, display panel, USB 3.0 port, etc. So unlike Apple it won’t just be a limited set of hardware components necessarily, but they will have to meet the specs to be supported by the Windows on ARM OS. This no doubt will make it much easier for Microsoft to keep it’s OS up to date as compared to say in the Google Android universe where the device manufacturers have to provide the OS updates (which in fact is not often as they prefer people to upgrade their device to get the new OS releases).
- Building Windows for the ARM processor architecture (Steven Sinofsky @ MSDN)
- Microsoft Unveils Its Next-Generation OS, Windows 8 (bits.blogs.nytimes.com)
- Microsoft plans Windows 8 ARM presentation at Mobile World Congress (slashgear.com)
- Live from the Windows 8 on ARM Preview event! (armdevices.net)