Duplicated-memory synchronization arrangement

Abstract From the Canadian patent

16-, A shared-buffer-memory-based ATM switch module (1) is duplicated (2) and operates in active-standby mode for fault-tolerance. Following failure and repair of a module, buffer memory (12) contents of the two modules are resynchronized as follows. At the time of commencing the synchronizing contents of the memory of, the standby repaired, module are cleared, all writes to the active module's memory also commence to be made to the standby module's memory and track begins to be, kept of overwriting of the contents of the active module's memory that existed at the time of commencing the synchronizing. This is done by a function (FIG. 4) whichsets a flag (64) in a queue-length-counter …