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. 27, 2001
Filed:
Aug. 24, 1998
Alexander Edward Okpisz, Austin, TX (US);
Thomas Albert Petersen, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Data loaded from system memory to a cache within a multiprocessor system is set to the exclusive coherency state if no other cache or processor has a copy of that data. Subsequent accesses to the data by another processor or cache which are snooped by the data owner result in an exclusive intervention by the data owner. The data owner sources the data to and shares the data with the requesting device on a read and transfers exclusive ownership of the data to the requesting device on a read with intent to modify. Unmodified intervention with cache-to-cache transfers over possibly much slower accesses to memory is thus supported by the multiprocessor system without requiring additional tag or status bits in the cache directories, saving a significant area.