1. A method of determining cache memory, comprising the steps of: writing a replacement data pattern to a first addressable location of a cacheable portion of addressable space, thereby placing said replacement data pattern into a corresponding first addressable location in said cache memory and tagging said corresponding first addressable location in said cache memory; accessing a first predetermined number of remaining addressable locations in said cacheable portion of addressable space, thereby tagging corresponding remaining addressable locations in said cache memory; and reading said corresponding first addressable location in said cache memory to determine whether said replacement data pattern remains in said corresponding first addressable location in said cache memory, said chache memory being of a first perdetermined size if said replacement data pattern is not in said corresponding first addressable location in said cache memory.