3052	 Cold-Start vs. Warm-Start Miss Ratios	 In a two-level computer storage hierarchy miss ratio measurements are often made from a cold start that is made with the first-level store initially empty. For large capacities the effect on the measured miss ratio of the misses incurred while filling the first-level store can be significant even for long reference strings. Use of warm-start rather than cold-start miss ratios cast doubt on the widespread belief that the observed S-shape of lifetime reciprocal of miss ratio versus capacity curve indicates a property of behavior of programs that maintain a constant number of pages in main storage. On the other hand if cold-start miss ratios are measured as a function of capacity and measurement length then they are useful in studying systems in which operation of a program is periodically interrupted by task switches. It is shown how to obtain under simple assumptions the cache miss ratio for multiprogramming from cold-start miss ratio values and how to obtain approximate cold-start miss ratios from warm-start miss ratios. Miss ratio cold start warm start storage hierarchy lifetime function multiprogramming S-shape
