"A short while ago we started releasing Windows 8 to PC OEM and manufacturing partners," said Stephen Sinofsky, the president of Microsoft's Windows group, in a Wednesday.

"Kudos to them for managing the process," said Michael Cherry, an analyst with Directions on Microsoft. "It's an important milestone, so congratulations. But it's just the first step."

As Cherry noted, RTM is a major mark in Microsoft's development process. It signals that the completed code is ready to send to computer makers, other hardware partners who need to test their device drivers and software, and to outside developers working on compatible programs.

The news was not unexpected: Two weeks ago when , it said that it would reach RTM the first week of August.

Some users will have access to the Windows 8 final code months before October. Developers and IT professionals who subscribe to MSDN (Microsoft Developers Network) will be able to download the new operating system starting Aug. 15. TechNet subscribers can download a trial of Windows 8 RTM that same day.