Enterprise customers who participate in the Software Assurance program will get access to Windows 8 as early as August via download, according to Microsoft.

The RTM and shipping dates didn't come as a surprise to at least two analysts.

"The dates are where we would expect them to be," said IDC analyst Al Gillen. "Microsoft had to hit an August RTM for Windows 8 devices to be ready for the holiday shopping season."

Gillen doesn't expect enterprises to rush to adopt Windows 8, primarily because most enterprises have either recently migrated or are in the midst of migrating to Windows 7.

It will be a different story in the consumer market, where makers of PCs, laptops and tablets will quickly adopt Windows 8, making it difficult for individual buyers to find a Windows 7 machine in a matter of months after the new OS becomes available, he said.