Holy shit
"Second, Microsoft has developed Azure Stack OS, the #Linux-based operating system that will run on those chips — Smith says that while Microsoft is a "Windows company," a full-fledged version of its flagship operating system was too big and too unwieldy for what it had in mind."
http://www.businessinsider.com/microsoft-azure-sphere-is-powered-by-linux-2018-4?r=US&IR=T&IR=T