Patent ID: 6389423
Filing Date: 2002-05-14
Classification: G06F,Y10S

Abstract:
A data communication device connected to a communication mechanism which connects to another data communication device, comprising:a shared data storing unit for storing a shared data replicated and managed by the data communication device and the another data communication device; a shared data updating unit for updating the shared data stored in the shared data storing unit; a version managing unit for storing and managing a version of the shared data; a version communication unit for communicating the version of the shared data by using the communication mechanism; an update data communication unit for communicating a update data which is a differential data between the shared data before updating and the shared data after updating by using the communication mechanism; wherein the data communication device executes a plurality of processes as a transmitting side data communication device when the shared data updating unit updates the shared data stored in the shared data storing unit (case (1)), the plurality of processes includes a process A by the version managing unit, for creating the version of the shared data updated by the shared data updating unit and storing the created version; a process B by the version communication unit, for transmitting the version stored in the version managing unit; and a process C by the update data communication unit, for transmitting the update data which is a differential data between the shared data before updating and the shared data after updating; wherein the data communication device executes a plurality of processes as a receiving side data communication device when the another data communication device updates the shared data stored in the another data communication device (case (2)), the plurality of processes includes: a process D by the version communication unit, for receiving the version transmitted from the another data communication device; a process E by the update data communication unit, for receiving the update data transmitted from the another data communication device; a process F by the version managing unit, for deciding whether to apply the update data based on the version stored in the version managing unit and the version received by the version communication unit, and for storing the received version when the version managing unit decides to apply the update data; a process G by the shared data storing unit, for storing the update received data when the version managing unit decides to apply the update data.