Microsoft announces the full selection of Windows 8 editions-- Windows 8, Windows 8 Pro, Windows 8 Enterprise and, perhaps most interesting of all, Windows RT (aka Windows on ARM or WOA).
Windows 8 is the generic consumer edition, for use in 32- and 64-bit x86 machines (both PCs and tablets, Microsoft says), while Windows 8 Pro is the enhanced enthusiast/professional/business edition.
Enterprise customers get Windows 8 Enterprise (obviously), with features such as PC management and deployment, advanced security, virtualisation and mobility scenarios.
The most interesting edition, however, remains Windows RT-- Windows ARM machines. In a drastic change, Microsoft will not be selling Windows RT separately, instead only pre-installing it in devices.
Windows RT includes a stripped-down version of the Office suite, but cannot handle desktop apps-- it even lacks Windows Media Player and most enterprise features from Windows 8 Pro and Enterprise.
Further separating Windows on ARM from other Windows editions is WinRT-- a new Windows runtime making "the foundation of a new generation of cloud-enabled, touch-enabled, web-connected apps of all kinds."
Microsoft insists "all editions of Windows 8 offer a no-compromise experience," even if the ARM edition appears to be something of a different beast from the rest of the OS family. We will know more once Windows 8 hits the market (once that actually happens).