from Scott on the mailing list :
Well, what can we reuse from CP/M?
None of the devices in our hardware are compatible with CP/M, the file system is probally too limited for something that large, so we would have to graft new drivers on to it.
All the programs expect completely different hardware for display, keyboard input and sound, we would have to recompile/port/modify every app you want to run or write wrappers.
As far as I can tell, only the 16bit version gained multitasking support, so its a single task kernel. Even worse there is no such thing as a single task kernel, its probably more like a library of function calls, none of which can do anything much without new drivers.
The interface is text based, so we can't use it.
So all we will be doing is dragging around a huge chunk of legacy code, which is next to useless. its way faster just to write our own kernel (its actually surprisingly easy if you know assembly)