Patent Number: 6,311,253

Title: Methods for caching cache tags

Abstract: A method for storing information in a computer memory system includes maintaining an M.sup.th level storage system including an M.sup.th level data store for storing data, an M.sup.th level full directory for storing a set of tags corresponding to the data, and an M.sup.th level partial directory for storing a subset of the tags. The partial directory is accessible faster than the full directory. Upon an M-1 level miss corresponding to a request for data, a congruence class corresponding to the request is fetched from the partial directory when it is present therein; otherwise, it is fetched from the full directory. The requested data is retrieved from the data store when it is present in the congruence class; otherwise, it is retrieved from a next level of the memory system. The tags in the partial directory may be full tags, partial tags, or a combination thereof.

Inventors: Chang; Albert (Yorktown Heights, NY), Charney; Mark (New York, NY), Montoye; Robert K. (New York, NY), Puzak; Thomas R. (Ridgefield, CT)

Assignee: International Business Machines Corporation

International Classification: G06F 12/08 (20060101); G06F 012/08 ()

Expiration Date: 10/30/2018