The beauty of Inferno is that one of the incarnations happens to be an operating system that runs on bare metal. But the very same code can be run as a command line program in Windows / OpenBSD / OSX / Linux. Or as a multi-windowed program like an MDI or a single window, or a full screen window in kiosk mode, or as a network service on IBM's Blue Gene.
Inferno is used by IBM, NASA, Alcatel-Lucent, the US DoD.
Bruce Ellis (one of the people who created Mark V Shaney) and one of the original Inferno developers until it was sold, has been working on a Verilog cpu to execute DIS natively but still no prototype.
One of the beauties of Inferno is it will run on a platform with no hardware MMU.
And the Styx protocol means it can do great things easily. It has even had servers running on Logo Mindstorm.
Inferno is used by IBM, NASA, Alcatel-Lucent, the US DoD.