bill - 1:18 am on Apr 17, 2012 (gmt 0)

Announcing the Windows 8 Editions [windowsteamblog.com] First, Windows 8 is the official product name for the next x86/64 editions of Windows. For PCs and tablets powered by x86 processors (both 32 and 64 bit), we will have two editions: Windows 8 and Windows 8 Pro. ... Windows RT is the newest member of the Windows family – also known as Windows on ARM or WOA

This is a much smaller number of versions that they usually issue for a major release of Windows.