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United States Patent  [\\] Patent Number: 5,247,673
Costa et al.  Date of Patent: Sep. 21,1993
 MULTIPROCESSOR SYSTEM HAVING
DISTRIBUTED SHARED RESOURCES AND
DYNAMIC GLOBAL DATA REPLICATION
 Inventors: Maria Costa, Buccinasco; Carlo
Leonardi, Legnano, both of Italy
 Assignee: Bull HN Information Systems Italia S.p.A., Italy
 Appl. No.: 614,804
 Filed: Nov. 16,1990
 Foreign Application Priority Data
Dec. 4, 1989 [IT] Italy 22593 A/89
 Int. CI.' GOoT 15/16
 U.S. CI 395/650; 364/DIG. 2;
364/974.7; 364/964.27; 364/946.6; 364/971.0;
364/DIG. 1; 364/228.1; 364/282.4; 364/254.3  Field of Search 395/650
 References Cited
U.S. PATENT DOCUMENTS
4,620,276 10/1986 Daniell et al 364/200
4,928,224 5/1990 Zulian 364/200
EP-A-081 056 (IBM) Abstract; p. 4, paragraph 2; claims 1-2.
Cern Conference Proceedings, Geneva, Oct. 7-8, 1985, pp. 283-290; J. Zalewsk, "An approach to program
ming multimicroprocessor bus systems", p. 285, Section 3, p. 286, Section 4.
GB-A-2 206 714 (Singer) Abstract; FIG. 1, Claims 1-4; p. 5, paragraph 1-p. 6, paragraph 2. AFIPS Conference Proceedings, Anaheim, Calif. May 16-19,1983, pp. 557-564; S. L. Lillevik, et al., "A multiprocessor with replicated shared memory", FIG. 15, p. 560, paragraph 2, line 20.
Primary Examiner—Gareth D. Shaw
Assistant Examiner—A. Katbab
Attorney, Agent, or Firm—Faith F. Driscoll; John S.
A multiprocessor system has distributed shared resources and dynamic global data replication in which a plurality of processors communicate each with the other through a system bus. Each CPU is provided with a local memory for storing data used locally and global data shareable by a plurality of processes operative in different CPUs and therefore replicated in the local memory of each CPU. Global data replication is performed at page level only when a global data page is effectively needed by a plurality of processes operative in different CPUs so that memory space required for replication is minimized as well as traffic on the system bus for global data replication and global data writes required for ensuring global data consistency.
7 Claims, 7 Drawing Sheets