Electrical computers and digital processing systems: memory – Storage accessing and control – Hierarchical memories
Reexamination Certificate
2004-03-25
2008-01-22
Bragdon, Reginald (Department: 2189)
Electrical computers and digital processing systems: memory
Storage accessing and control
Hierarchical memories
C711S137000, C711S141000, C711S147000
Reexamination Certificate
active
07321956
ABSTRACT:
A system for cache coherency comprises a memory. The memory comprises a plurality of data items and a plurality of directory information items, each data item uniquely associated with one of the plurality of directory information items. Each of the plurality of data items is configured in accordance with one of a plurality of access modes. Each of the plurality of directory information items comprises indicia of the access mode of its associated data item. A multiplexer couples to the memory and comprises a multiplex ratio. A plurality of buffers couple to the multiplexer and to the memory. The multiplex ratio is a function of the number of buffers in the plurality of buffers. A plurality of multiplexer/demultiplexers (MDMs) each uniquely couple to a different one of the plurality of buffers. A plurality of processing elements couple to the memory; each of the processing elements uniquely couples in a point-to-point connection to a different one of the plurality of MDMs. Each of the processing elements is configured to transmit a data request to its associated MDM, the data request identifying one of the plurality of data items and an access mode. Each of the processing elements further comprises a prefetch page cache, the prefetch page cache configured to store a subset of the plurality of data items and the plurality of directory information items. The memory is configured to transmit a data response to each of the processing elements in response to a data request, the data response comprising the identified data item and its associated directory information. Each of the processing elements is farther configured to receive the data response and to compare the associated directory information with the access mode of the data request and in the event that the associated directory information and the access mode of the data request are not compatible, to initiate coherence actions for the requested data item.
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Gschwind Michael Karl
Johns Charles Ray
Truong Thoung Quang
Bragdon Reginald
Carr LLP
Gu Shawn X.
Rifai D'Ann N.
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