Priority paging algorithms and the extension problem

Given a particular computer system the extension problem concerns the prediction of performance when the size of main memory is increased. In this paper a specific approach to this problem is formulated for demand paging systems. A necessary and sufficient condition on the nature of page replacement rules which leads to solutions of the extension problem is a major result of the paper. As the other principal result we show that the class of replacement rules so defined is precisely that class of rules having the wellknown inclusion property. The paper concludes with a general discussion of topics related to the extension problem.