Patents by Inventor Michael P. Witt

Michael P. Witt has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Coherence control by data invalidation in selected processor caches without broadcasting to processor caches not having the data
    Patent number: 5265232
    Abstract: A coherence directory and its methods of operation are disclosed for private processor caches in a multiple processor system to control data coherence in the system. It provides cross-invalidate (XI) controls for the assignment of exclusive and public ownership to data units in the processor caches, including required cross-invalidation of data units among the processor caches to obtain data coherence in the system in an efficient manner. The coherence directory can be used in a multiple processor system with or without any shared second level (L2) cache, shared or private. When a shared L2 cache is used to improve system access time, the coherence directory can also be used as the second level directory for the shared L2 cache and eliminate the need for any additional L2 directory(s).
    Type: Grant
    Filed: April 3, 1991
    Date of Patent: November 23, 1993
    Assignee: International Business Machines Corporation
    Inventors: Patrick M. Gannon, Michael Ignatowski, Matthew A. Krygowski, Lishing Liu, Donald W. Price, William K. Rodiger, Gregory Salyer, Yee-Ming Ting, Michael P. Witt