Now that Microsoft has freed Windows Vista from the shackles of a five year development process, the company is attempting to the wow starts now us by revealing that it plans to have its next major operating system ready within the next two-and-a-half years, giving Vista's successor an expected release date of late 2009. Speaking to PC World, Ben Fathi, the executive in charge of the OS's core components, made it clear that he was referring to a whole new OS -- known to have the codename "Vienna" -- and not the upcoming Vista service pack, codenamed "Fiji." Other than this tentative release date, Ben didn't have much new information on the future for Windows: in response to the question of what Vienna's killer feature will be, he said "I don't know what it is" and then proceeded to suggest that full virtualization and a radical new user interface will be the aim. Both of these suggestions lend credence to previous reports that a break in compatiblity with older applications and a new user interface would be Vienna's flagship features. Now all we've got to do is wait (and hope that the changes aren't too radical.)