3067	 Generalized Working Sets for Segment Reference Strings	 The working-set concept is extended for programs that reference segments of different sizes. The generalized working-set policy GWS keeps as its resident set those segments whose retention costs do not exceed their retrieval costs. The GWS is a model for the entire class of demand-fetching memory policies that satisfy a resident-set inclusion property. A generalized optimal policy GOPT is also defined at its operating points it minimizes aggregated retention and swapping costs. Special cases of the cost structure allow GWS and GOPT to simulate any known stack algorithm the working set and VMIN. Efficient procedures for computing demand curves showing swapping load as a function of memory usage are developed for GWS and GOPT policies. Empirical data from an actual system are included. Database referencing memory management optimal memory policies paging program behavior program measurement segmentation working sets
