Title: Cache management using historical access information
Type: issued patent
Patent number: 7,177,984
Issue date: February 13, 2007
Filing date: April 16, 2004
Link to PDF: 
(9 pages)
AIPW Summary: A cache priority for an item is calculated based on access frequency, retrieval cost, and item size. The cache priority is dynamically updated as items are accessed. The cache priorities are used to determine which items remain in the cache when the cache is running low on space. The claims of this patent are fairly broad and follow the basic overview above.