Comment by joelangeway

The original machine that influenced C's model of computers was the PDP-11 (http://en.wikipedia.org/wiki/PDP-11). It had a mov instruction instead of load/store. It had no dedicated IO instructions. It could be treated as a sort of generic random access machine (http://en.wikipedia.org/wiki/Random-access_machine) and that is what C did and still does. So there was a reality that C simply modeled, and it was copied (with all sorts of modifications) many times.