System for coordinating coherency of cache memories of multiple host computers of a distributed information system

摘要

Apparatus and method for coordinating cache coherency between host cache memories in a distributed information system in a system which comprises at least one main storage memory coupled to a plurality of host computers through controllers. Each host computer includes a host cache controller which maintains the state of the data stored in its associated memory and maintains communicating with a main memory controller for participating in the control of coordinated reading and writing of data between the host cache memories and the main storage memory. The system maintains cache coherency by the exchange of commands between the main memory controller and the hosts cache controllers each of which define the state of the blocks of data stored in the host cache memories.