I'm pretty sure the "2 OS'es" term is not correct. If the device is WinCE, it's ONE OS and it's WinCE. However, manufacturers may choose to run a "shell" that is locked and has to be modded to run other external proggy such as Nav. "Unlocking" is the term widely used. Cheap chinese made "clones" shouldn't have to be "unlocked" WinCE has ability to switch between different tasks (proggies running or pausing in background); perhaps that is what you mean.