Humble with regard to virtual storage.

Looking back at the late 1960s, Dijkstra mentioned that progress had been made in processor allocation, mainly due to the work of his students Bomhoff and Feijen. With respect to virtual storage implementations, however, Dijkstra humbly admitted that much had still to be done on this subject. Even though he had spent months trying to do so, he was stil not able to find the right abstractions. [EWD300]