Patent ID: 7093078
Filing Date: 2006-08-15
Classification: G06F

Abstract:
1. A data access method used in a network system having several node devices connected for communications configured so that each node device can execute certain processing by accessing memories in said several node devices or cache memories at a higher access speed, said method comprising: in each node device: wherein said tag information indicates a data storage status comprising one of three possible states, including: wherein said deciding whether or not to abolish the data acquired from said memories by said speculative access is based upon a logical combination of five bits of information defining a status of said speculative access, said five bits of information comprising: an “LV” bit that shows that reply data by a speculative read oath has been returned from a local memory; a “TV” bit that shows that a read type transaction has been received from a processor and issued; an “HV” bit that shows that reply data has been returned from a memory unit mounted on an other node; a “CV” bit that shows that modified data held in the cache of a remote node has been returned; and a “JV” bit that shows a snoop result being a “Modify found” bit that defines whether said data has been found to be currently in a cache memory in one of said node devices in said system, and wherein said cache data is abolished when one of said following conditions exist: