I know that two operating systems can share the same computer through hosting. For example, WINE can host Windows, or vice versa, Virtual Box can host a Linux system on a Windows box, but in both cases only one operating system is actually controlling the motherboard and is providing interfaces to the hosted OS.
Is it possible to configure a system to actually share a motherboard between two operating systems?
For this to work, the motherboard would probably have to have two CPUs and also some way to split the memory. Also, you would probably need two video cards and a way of dedicating peripheral slots to one OS or the other.