Microsoft will issue a "release preview" of Windows 8 to consumers the first week in June, meaning the new operating system is nearly finished three to four months ahead of its expected release.

Stephen Sinofsky, Windows president, made the announcement at a developers meeting in Tokyo Tuesday, and Microsoft shared the news on Twitter.

In past years, when Microsoft has worked up to final releases of its operating system, it has called such versions "release candidates."

"The Windows Team appears to be not only reimagining Windows for Windows 8, but also reimagining the names of all their development process milestones," Michael Cherry of Directions on Microsoft, an independent firm that analyzes Microsoft's technologies and strategies, told

"The current release, which is referred to as a Customer Preview, would have in the past been called a beta. The next release, which now appears to be scheduled for June, is apparently being called a release preview. Formerly this would likely have been simply called a release candidate."

Microsoft started offering a free consumer preview of Windows 8 in late February. While the company isn't sharing specifics on how many people are taste-testing Windows 8, it said earlier this month, also on Twitter, that so far "Windows 8 consumer preview usage (is) more than twice Windows 7 beta at the same point in time. Millions of people using everyday."

The significance of the "release preview" means that "for all intents and purposes, they are done," with Windows 8, Cherry said.

"They have established some form of internal test criteria, such as no new bugs found for a period of time, and they want to run a final set of tests run before releasing to manufacturing. They want to make sure there is nothing they have missed, and that the code is both stable and performing (speed of processing and battery life) the way they want it to prior to release to manufacturing."