The operating system was unveiled at the TechFest 2008 research event in Redmond, and will be made available at no charge for academic and non-commercial use.
Microsoft said that Singularity will help to improve software dependability, and foster inventive research in systems, programming languages and tools.
Rick Rashid, senior vice president of Microsoft Research, told the TechFest audience of customers, academics, dignitaries and media representatives: "Computing impacts every facet of our lives, from the way we work to the way we learn and live.
"Our job in research is to continuously advance technology to make our lives better in tangible ways.
"Singularity is not the next Windows. Think of it as a concept car: a prototype operating system designed from the ground up to test-drive a new paradigm for how operating systems and applications interact with one another.
"We are making it available to the community in the hope that it will enable researchers to try out new ideas quickly."
Singularity can be downloaded from CodePlex, an online Microsoft portal created in 2006 to foster collaborative software development projects and host shared source code.
Rashid also showed off a project called BEE3, a hardware platform that lets researchers experiment with different computer architectures without using costly custom chips.
He also highlighted multiple projects aimed at advancing the understanding of natural ecosystems.
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