The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 23, 1993
Filed:
Apr. 03, 1991
Patrick M Gannon, Poughkeepsie, NY (US);
Michael Ignatowski, Red Hook, NY (US);
Matthew A Krygowski, Hopewell Junction, NY (US);
Lishing Liu, Pleasantville, NY (US);
Donald W Price, Lake Katrine, NY (US);
William K Rodiger, Sudbury, NY (US);
Gregory Salyer, Woodstock, NY (US);
Yee-Ming Ting, Cornwall, NY (US);
Michael P Witt, Fishkill, NY (US);
International Business Machines Corporation, , NY (US);
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).