Microsoft has a long history of selling its business-oriented OSs well past the time they've been replaced by a new version. But with the ill-received Windows Vista, the software giant might pursue a different tactic and stop selling Vista as soon as Windows 7 emerges in final form. Even more remarkable—if this is true—is that Microsoft has already committed to continuing selling Vista's predecessor, Windows XP, after Windows 7 is finalized.

"We are still not sure if \[PC makers\] will be able to ship Vista once Windows 7 is made available," Microsoft General Manager Richard Francis said. "Having said that, an enterprise customer that purchases a PC with Windows 7 pre-installed is allowed to downgrade to Vista should they desire, similar to what we have today on Vista to XP."

If Microsoft does effectively stop offering Vista when Windows 7 appears, that won't change the Vista support picture at all, of course. Microsoft will continue to support Vista through April 2012, according to the current schedule.

And to be fair to Vista, Windows 7 is simply an evolution of that OS and arguably just a fairly minor upgrade, one that runs faster than its predecessor and offers some interesting usability improvements. It's hard to imagine many customers wanting Vista after Windows 7 ships, even if the older OS is still made available for sale.

"It's been a long time since we've had a version of Windows that will actually run better \[than its predecessor\] on the hardware that most customers \[already\] have," Microsoft Corporate Vice President Mike Nash said last week, hinting at Vista's fate