Generalities:

Need to clear up the '_set_' versus 'into action' timing so that _get_
always returns the currently functioning value ...

Specifics:

DOS   : seems fine.
Linux : rts twiddling for users and lsr/msr handling
        space and mark parity not implemented properly
	not sure if either flow control works
Unix  : As linux, also no IRQ/io address control.
Others: everything
