Now that Windows XP has reached its official end of life, we can start talking about the OS in past tense (sort of). The same applies to Bill Gates, the Harvard dropout gone billionaire, who recently relinquished the reigns and stepped foot into semi-retirement. The former CEO's passing of the guard might have left many wondering what Microsoft's future will look like in life after Gates, but what about life after Windows?

It might sound preposterous, but don't tell that to the Microsoft Research team who, for the past several years, has been working on Singularity, an entirely new system-architecture and operating system built from the ground up. Comprised of only a few hundred-thousand lines of code, not only is Singularity entirely different from Windows, but the source code, build tools, test suites, design notes, and other background materials are all readily available, provided you're able to sign a non-commercial, academic Shared Source license. And that's not the end of it - Singularity Version 2 will bring multi-core computing into the mix.

But it's not what we know about Singularity that's so interesting, it's what we don't know about a Singularlity-derivative, code named Midori, that's sparking questions about the future of Windows. According to Mary Jo Foley, ZDNet blogger and author of Microsoft 2.0: How Microsoft Plans to Stay Relevant in the Post-Gates Era, Midori is a new operating system platform that supposedly supersedes Windows. Adding to the shroud of mystery, Foley reports that Eric Rudder, senior VP and one-time Gates heir-apparent, is spearheading the project. She goes on to cite an anonymous Microsoft tipster who claims, "everyone under him is a multi-year vet, has a super fancy title, and is going back to their roots and writing code like they probably did in the old days." If true, that would certainly seem to indicate that there's something much larger brewing than an academic OS, but will it supplant Windows? If Rudder knows what Microsoft has planned for Midori, he isn't saying, nor is anyone else at Redmond. And with Windows 7 already slated for 2010, don't expect to solve this one anytime soon.