"Datum processing," "digital datum transmission," and "automaton theory\´\´

The terms "datum processing," "digital datum transmission," and "automaton theory" may seem awkward to persons who are accustomed to the more common "data processing," "digital data transmission," and "automata theory" (this last term being used, for example, in Part A of the Reviews Section of the IEEE Transactions on Electronic Computers). The author discusses if it would not really be more appropriate to use the the singular forms.