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:
Jul. 11, 2000
Filed:
Feb. 26, 1998
Toshiaki Tarui, Sagamihara, JP;
Koichi Okazawa, Ebina, JP;
Yasuyuki Okada, Yamato, JP;
Toru Shonai, Kodaira, JP;
Toshio Okochi, Kokubunji, JP;
Hideya Akashi, Hachiouji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A shared memory multiprocessor (SMP) has efficient access to a main memory included in a particular node and a management of partitions that include the nodes. In correspondence with each page of main memory included in a node, a bit stored in a register indicates if the page has been accessed from any other node. In a case where the bit is '0', a cache coherent command to be sent to the other nodes is not transmitted. The bit is reset by software at the time of initialization and memory allocation, and it is set by hardware when the page of the main memory is accessed from any other node. In a case where the interior of an SMP is divided into partitions, the main memory of each node is divided into local and shared areas, for which respectively separate addresses can be designated. In each node, the configuration information items of the shared area and the local area are stored in registers. The command of access to the shared area is multicast to all of the nodes, whereas the command is multicast only to the nodes within the corresponding partition when the local area is accessed.