Microsoft has taken the somewhat radical decision to split its next Windows into two wholly different versions – one an updated version of the current system, the other a lot more like Apple’s iOS.

By the end of this year Windows 8 should be out. After the long-awaited Windows Vista was greeted by tech people and the public with a mighty “meh,” Microsoft shook up the leadership of its Windows group and they pretty quickly came up with the vastly superior Windows 7 – an OS that, to my mind at least, does many important things like window management and task switching significantly better than Apple’s OSX. However, the arrival of mass market tablet computing in the form of the iPad and its many competitors has forced Microsoft to rethink everything again, and Windows 8 will have a completely revamped user interface based on the much-praised Windows Phone 7/7.5 (used, for example, on Nokia’s newish Lumia 800).

This new UI is called Metro and its main feature is that rather than having icons that represent your device’s applications and files and so on, it uses “live tiles” that update themselves with relevant information without you needing to activate them. It also has a completely different look to previous iterations of Windows and to Apple’s iOS and Google’s Android. Here’s a picture.

Windows 8 tiles, from

But what I wanted to talk about was this forking of Windows into two different streams, which is not something you actually see as a user but which rather fundamentally changes the computer. It is a technical thing that I am not sure I can adequately explain, but broadly, there will be a version of Windows 8 that works on ARM processors – which are the type used in most mobiles phones and tablets – and another that works on x86 processors – which run most desktop and laptop PCs. The crucial issue is that applications written for one version will not work on the other, so if you have a Windows 8 laptop that uses the x86 version and a Windows 8 tablet that uses the ARM version, you won’t be running the same stuff. They will also be different in the manner in which iOS differs from OSX or Windows: the ARM Windows 8 will only be able to install and run applications that are acquired through Microsoft’s version of the App Store – i.e. Microsoft will control distribution and will have to approve all the apps. This is a radical departure from the current PC landscape, in which anyone can write an application and throw it up on the internet for anyone else to install. In fact to some extent this openness is what defines the PC: it is a set of open standards that allow anyone to get involved by producing their own hardware and/or software, and it’s all interoperable.

There’s a discussion of this forking in this rather good article by someone who knows what they’re talking about. My brief comment is that Microsoft are risking creating a lot of confusion among users about what they can and can’t do with their computer. It will be possible to own three devices all running “Windows” (i.e. a Windows phone, a Windows ARM tablet and a Windows x86 PC) – with an interface that looks just about identical, but which are all capable of running a different library of programs. Microsoft seems to want to have what Apple currently has – i.e. complete control over an entire software ecosystem (iOS), but not give up on what it already has (the biggest open computing platform). You can sort of see the outlines of a master strategy, a sort of One Windows to Rule them All, but they will need to be extremely clever with their branding, marketing and communications around these new Windows devices if it’s all going to work.