Untersuchungen über Seitenaustauschverfahren unter besonderer Berücksichtigung von Prepaging Konzepten und der Bewertung ihrer Leistungsfähigkeit

Paged virtual memory is a commonly realized concept of storage organization in existing operating systems; therefore paging algorithms which control the flow ofinformation between memory and secondary storage are major components of these systems. In almost all existing systems page transport from secondary storage to main memory is realized on a demand basis; prepaging is an alternative which has not yet received too much attention. In addition to investigations of general properties (absence of abnormal behavior, implementation overhead, etc.) the relative performance of demand paging algorithms and prepaging algorithms is focussed in this report. Several optimal prepaging algorithms are defined and proved to outperform comparable optimal demand paging algorithms with regard to the selected performance criteria. In the class of non-optimal (realizable) paging algorithms a set of prepaging algorithms is introduced which consist of a combination of one of the well-known replacement policies with a prepaging fetch policy based on information which can be extracted from the program reference behavior observed during prior execution. In extensive simulations the performance of these algorithms is shown to be superior to that of the basic demand paging algorithms for a wide range of program behavior