Abstract: As copies of data from a main memory are stored in a cache memory of a processor of a computer system as original data, the addresses of those copies are stored successively in a queue. Once the depth of the queue is reached, the storage of each new address in the queue causes a previously stored address to be output from the queue. For each address output from the queue, the corresponding original data in the cache is returned to the main memory. The amount of original data stored in the cache is therefore limited. Preferably, the queue comprises a first-in, first-out queue, and the depth of the queue is programmable.