And as I’ve been saying all along, the past (i.e. Windows 7 and its schedule) is a great indicator of what will happen this time.

Speaking at the start-up LAUNCH event at the Microsoft Silicon Valley campus this week, Microsoft Corporate VP Dan'l Lewin had the following to say about the schedule for Windows 8:

“We will be in market … if you look at the crystal ball and just say what happened in the past is a reasonable indicator of what our forward looking timelines will be and just speculate, we've made the point about having a developer conference later this year, and then typically we enter a beta phase, and then in 12 months we're in the market, so let's make that assumption.”

That developer conference, BUILD, happens in September. So September 2011 + 12 months is of course September 2012. Microsoft previously RTM’d Windows 7 in September 2009, exactly three years before that date.