Abstract text

Apparatus, methods, and program products for storing data address a first cache and a second cache. The second cache is capable of operating in a first mode wherein data read for storage in the first cache is also stored in the second cache, and is capable of operating in a second mode wherein the data stored in the second cache does not include at least some of the data read for storage in the first cache. The data stored in the second cache includes data that has been removed from the first cache. Thus the contents of the second cache are at least partially exclusive of the contents of the first cache. The described apparatus, methods, and program products are advantageously employed in multi-level caching systems wherein the caches may be approximately the same size.