Ever since the last quarter of 2006, when a survey was held on a Microsoft web site, where one of the questions towards the end of the survey was "Have you ever heard of Windows Mesa?", the question itself and the answer to it, has foxed many!
But it appears that codename "Vienna" (Blackcomb/Windows7) will be/has been re-codenamed as Windows MESA in its 5th phase of development. Is this true ? Your guess is as good as mine; but searching carefully...very carefuly can give one that impression. But then, whats in a name !? First Blackcomb; then Vienna, then Windows7 & now (?)Mesa(?).
Microsoft has officially said that the code name for this Vista follow-up is Vienna, but Microsoft Development VP Ben Fathi said he could not disclose the current name. "We've been told not to use it publicly" he said.
source :
http://www.winvistaclub.com