I just realized that “another operating system” can mean so many things that aren’t Windows.

We need to be patient and wait until some crazy people defile their Steam Machine for Internet points.

I found an answer on the Steam Machine page: Yes, Steam Machine is optimized for gaming, but it’s still your PC. Install your own apps, or even another operating system. Who are we to tell you how to use your computer?

Was it confirmed that you can install Windows? The video said software, I don’t remember that you could install any operating system. It comes with an Arch Linux.