Encore Computer Corporation

Steven J Frank

David J Schanin

Russel L Moore

John Reed Bartlett

Charles S Namias

Stephen S Corbin

David W Zopf

Brian D Gill

Mark J Matale

David F Ford

Andrew W Wilson, Jr

Trevor A Creary

Disclosed is a multiprocessor computer system including a plurality of processor modules with each of the processor modules including at least one processor and a cache memory which is shared by all of the processors of each processor module. The processor modules are connected to a system bus which comprises independent data, address, vectored interrupt, and control buses. A system memory which is shared by all the processor modules is also connected to the buses, and the cache memories in each processor module store those memory locations in the main memory most frequently accessed by the processors in its module. A system control module controls the operation and interaction of all of the modules and contains the bus arbiters for the vector, data and address buses. The system control module also controls the retrying of requests which are not completed and should any requester fail to obtain access to a bus, the system control module also unjams this deadlock. Each of these multiprocessor computer systems can be connected to another multiprocessor computer system through an interface which includes a cache for housing frequently accessed locations of the other multiprocessor system.

Multiprocessor computer system employing a plurality of tightly coupled

A caching system for a shared bus multiprocessor which includes several processors each having its own private cache memory. Each private cache is connected to a first bus to which a second, higher level cache memory is also connected. The second, higher level cache in turn is connected either to another bus and higher level cache memory or to main system memory through a global bus. Each higher level cache includes enough memory space so as to enable the higher level cache to have a copy of every memory location in the caches on the level immediately below it. In turn, main memory includes enough space for a copy of each memory location of the highest level of cache memories. The caching can be used with either write-through or write-deferred cache coherency management schemes.

Hierarchical cache memory system and method

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Westboro, MA, United States of America

Steven J Frank