[klodolph]

I’ve had coworkers who were on the original Xbox team and they told me that the OS was not Windows. One of the things about the Xbox OS is that the OS itself gets a fixed timeslice each frame to do whatever it needs while the game is running, in order to make it so the game can get the rest of the frame to run. This sounds to me like a decision that has far-reaching consequences.

I’m sure that it shares plenty code with Windows. You might say that the OS is based on Windows. But it’s definitely not Windows.

[est31]

Hmmm. So I estimated too much Windows in Xbox's OS. Thanks for your anecdotes.

[yjftsjthsd-h]

By that standard, is a Hyper-V server running Windows? AFAIK, that's also just running NT as a guest.

[numpad0]

I too remember the "Xbox kernel is not Windows" narratives in 2000s-2010s. Clearly Microsoft then considered it "not Windows", IIRC especially on Xbox 360. It's not that a VMM that reside parallel to the Xbox kernel makes it not Windows or not. Sometimes they said it's "built with technologies from Windows" or sometimes it was "built specifically for Xbox" but they maintained it's not Windows.

[pjmlp]

Yes, Hyper-V is a type 1 hypervisor, Windows is just another guest OS.