Among the details still missing about Windows 8 is the price of the operating system. Microsoft has not revealed pricing for "System Builder," the license required for home-built PCs and Macs adding a new virtual machine running Windows 8.

OEMs will have 10 fewer days to get Windows 8 on new hardware than they did three years ago when . Windows 7 hit retail on Oct. 25 of that year.

Beginning Aug. 15, when MSDN and TechNet subscribers can get their hands on Windows 8 RTM, developers will be able to upload their apps to the Windows Store, Microsoft's electronic market for Metro-style software that will run on both Windows 8 and its offshoot, Windows RT.

But while RTM is a crucial milestone, analysts still have concerns.

"At launch, the store needs at least 5,000 very-high-quality Metro apps," said Patrick Moorhead, principal analyst at Moor Insights & Strategy. "Otherwise, Microsoft will have an extremely hard time, if not an impossible time, selling a Windows 8- or Windows RT-based tablet."