2669	 A Simple Linear Model of Demand Paging Performance	 Predicting the performance of a proposed automatically managed multilevel memory system requires a model of the patterns by which programs refer to the information stored in the memory. Some recent experimental measurements on the Multics virtual memory suggest that for rough approximations a remarkably simple program reference model will suffice. The simple model combines the effect of the information reference pattern with the effect of the automatic management algorithm to produce a single composite statement the mean number of memory references between paging exceptions increases linearly with the size of the paging memory. The resulting model is easy to manipulate and is applicable to such diverse problems as choosing an optimum size for a paging memory arranging for reproducible memory usage charges and estimating the amount of core memory sharing. paging demand paging memory models program models performance measurement multilevel memory systems virtual memory associative memory memory usage accounting Multics
