Steven Sinofsky, president of the Microsoft Windows and Windows Live division, revealed the first details about Windows 8 on ARM (WOA) recently in the Building Windows 8 blog. Microsoft CEO Steve Ballmer got a lot of attention (not all positive) when he said, "There's nothing more important at Microsoft than Windows" earlier this year during his final keynote presentation at CES. However, with Windows 8 (currently in a pre-beta release phase) being split into versions for the x86/x64 desktop (Windows 8), phone (Windows Phone 8), and now ARM-based tablets (WOA), the question is: What exactly is Windows? Will Windows 8 (x86/x64, ARM, phone) fragmentation make Google's Android fragmentation look insignificant by comparison?
Most importantly, however, it does not run the same instructions as x86 processors from Intel and AMD, used by PCs running Microsoft Windows today. Microsoft supported multiple-processor architectures, up to and including, Windows NT 4 (prior to Windows XP). For example, some will remember that there were versions of NT 4 for the DEC Alpha, MIPS, and PowerPC processor architectures. Even today, Microsoft provides server versions of Windows for Intel's Itanium architecture, although it has announced that the current versions will be the last to support it.
The showstopper sentence in Sinofsky's blog item is this: "WOA does not support running, emulating, or porting existing x86/64 desktop apps." In other words: Microsoft Windows on ARM will not run any of the software currently running on Windows XP, Vista, or 7 today. This, in my opinion, removes much of the incentive to buy a tablet or other ARM-based computer running Windows 8. WOA tablets and ultrabooks will be no more compatible with your current Windows 7 desktop or notebook than the iPad; and, while Metro-style apps (Metro is the tiled, graphical user interface used in Windows Phone 7.5 and Windows 8) will run on both Windows 8 and WOA, they will not run on PCs running older Windows versions. So, while having a WOA tablet might an be incentive to run Windows 8 on a legacy desktop, there is not much incentive to have a WOA tablet just because you have Windows 7 (or even XP) on your desktop.
I installed Windows 8 Developer Preview the day it was released on September 13, 2011. It is running on a netbook with a multi-touch display that can be used in either a tablet or notebook configuration, and, while the Metro interface is nice to use with touch in a tablet form, I can see no compelling reason to move from Windows 7 to Windows 8 for all other software. In fact, the changes to the Windows desktop actually reduces some functionality for those of us who have used the current interface since the introduction of Windows 95. Large businesses, who are only now migrating from Windows XP to Windows 7, will have even less incentive than consumers because of the potential costs and productivity losses associated with the update process and with training.
There is, however, one possible big incentive for people to use WOA devices. Later in the same blog entry, Sinofsky announced that: "WOA includes desktop versions of the new Microsoft Word, Excel, PowerPoint, and OneNote." This will be a WOA version of the next version of Microsoft Office, code name Office 15. Presumably, this means that this version of Microsoft Office will be bundled with WOA like Microsoft Office for Windows Phone 7.5. However, the mobile version of Office for Windows Phone 7.5 consists of extremely scaled down versions of Word, Excel, PowerPoint, and OneNote. If this is the case with Office for WOA, then power Office users will have little incentive to use this version of Office. If this is the case, we will see fragmentation not only in Windows but also in Microsoft Office with separate versions with different capabilities for x86/x64 Windows, WOA, and Windows Phone. Although fragmentation might be mainly a concern for technologists, there will definitely be confusion for the general public if Microsoft says that PCs running Windows 8, tablets running WOA, and Windows Phone 8 smartphones are all based on the same platform. Many people will assume this means that the same software will run on all three platforms, and that simply is not the case.
Microsoft's Windows Vista provided little incentive for Windows XP users to upgrade. As it turned out, many Windows XP PC's could not run Windows Vista well. Windows 7 effectively addressed many of Vista's problem and has been considered successful by reviewers. Windows 8 might not have the performance issues Vista had, but it does not provide legitimate reasons to upgrade from Windows 7 unless you use a touch device.