[zokier]

From technical standpoint I'd guess that separating the game and "everything else" to different OSs allows tighter control of resources, ensuring that games run with consistent performance. It might not be completely unlike the approach taken by RTLinux <http://en.wikipedia.org/wiki/RTLinux>;

[fmstephe]

That does seem like a reasonable explanation. It would be great to hear from someone in the know though.

Couldn't follow that link, due to the '>'

http://en.wikipedia.org/wiki/RTLinux