An important resource allocation mechanism in virtual storage operating systems is the maintainence of the multiprogramming level in main storage, especially when some form of working-set storage management strategy is employed. Swapping of programs in and out of main memory occurs when sufficient storage becomes available and when total storage demand exceeds capacity. In this paper, we propose a class of swapping algorithms that couples storage management parameters with swapping decisions. An analytic model is developed and numerical results are presented to compare the performance of these algorithms. Copyright © 1977 by The Institute of Electrical and Electronics Engineers, Inc.