[kaushiks]

Microsoft's research OS was called Singularity [1] and the C# compiler (that compiled to native code) Bartok [2].

[1] http://research.microsoft.com/en-us/projects/singularity/ [2] https://en.wikipedia.org/wiki/Bartok_(compiler)

[michel-slm]

Singularity was later extended by the joint MS-MSR project Midori, which sadly was discontinued last year. Apparently some features are being incorporated into C#.

Joe Duffy is blogging about his experience: http://joeduffyblog.com/2015/11/03/blogging-about-midori/