Microsoft splits Windows 8 into Windows 8 (x86) and Windows RT (ARM)

In a blessed moment of clarity, Microsoft has announced that there will be just three flavors of Windows 8 for consumers: Windows 8, Windows 8 Pro, and Windows RT. This is in stark contrast to Windows 7 and Vista, which were split into more SKUs than there are days in the week.
The default version — 32- and 64-bit Windows 8 for x86 PCs and tablets — replaces Windows 7 Home Basic and Home Premium. Windows 8 Pro, with features like BitLocker and Remote Desktop, replaces Windows 7 Professional and Ultimate (for a full breakdown of the features in each SKU, see the table at the end of this story). There will also be an Enterprise edition of Windows 8, for enterprise customers.
But let’s talk about the black sheep: Windows RT. It’s not Windows 8 RT, or Windows 8 for ARM, or Windows on ARM — it’s Windows RT. Microsoft doesn’t state what the “RT” moniker means, but it’s almost certainly short for WinRT, the new runtime library that underpins the new tile-based Metro interface. Windows RT has a feature set similar to normal Windows 8, but it lacks Storage Spaces, Windows Media Player, and it can’t install x86/64 software (obviously). Windows RT comes with a free copy of Microsoft Word, Excel, PowerPoint, and OneNote, while Windows 8 and Pro do not.
There are a few possible reasons for the name change. First, because it isn’t a direct upgrade from Windows 7, it probably prevents Microsoft Volume Licensing partners from gaining free access to Windows RT. More importantly, though, Windows RT will only be available as a pre-installed OS. You will not see a Windows RT box on a shelf at Best Buy — there won’t be any confusion about whether the version of Windows 8 you are buying will work on your PC or not.
This also means that you won’t be installing Windows 8 on your ARM Android/iOS/Palm tablet — at least not legitimately. I would be surprised if there isn’t an enterprise version of Windows RT that IT admins can use to bulk provision ARM tablets.
It will be very interesting to see if tablets are advertised as running Windows 8 or Windows RT. Windows 8 has a huge amount of cachet attached to its name, while Windows RT means virtually nothing to consumers. Will Microsoft water down its impending advertising blitz by drawing a line between its x86 and ARM ecosystems, and with repeated mentions of Windows RT? In my opinion, Microsoft’s success on the tablet hinges almost entirely on leveraging the success of Windows 7 — though, who knows, maybe Windows RT will have enough third-party app support that it can stand on its own. Irrespective of nomenclature, Microsoft will have a unified UI across smartphones, tablets, laptops, desktops, and game consoles — and that alone should be enough to drive a lot of consumer interest in all five platforms.