The system call interface to perform I/O cannot be described as "memory mapped"; the read/write system calls are programmed I/O. The opposite of memory mapped. You're letting terminology get you into trouble. You should just let go of your definitions and make the broader point you're trying to make, which might still be salvageable.
I agree, "memory mapped" is the wrong term. I was just letting the original poster who called it this way keep that as a concession or a mental model. That was my mistake as it just confuses everyone even more.
