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US006202085B1
(12) United States Patent ao) Patent No.: us 6,202,085 Bi
Benson et al. (45) Date of Patent: *Mar. 13,2001
5,790,789 * 8/1998 Suarez 395/200.32
OTHER PUBLICATIONS
Martin, James, Design and Strategy for Distributed Data
Processing, Prentice Hall, Inc., pp. 272-306, 1981.*
* cited by examiner
Primary Examiner—Zarni Maung
Assistant Examiner—Gary Scott Fourson
(74) Attorney, Agent, or Firm—Workman, Nydegger &
Seeley
(57) ABSTRACT
A system and method for incremental change synchronization among multiple copies of data is disclosed. To achieve the synchronization a genera synchronization model is used. The synchronization model establishes a one-way data flow path to allow incremental changes to be transferred from a copy of data that incorporates the incremental changes to a copy of data that does not yet incorporate the incremental changes. To achieve this one-way data flow path, the synchronization model uses an agent, a data collector, and a data synchronizer. The data collector collects incremental changes transferred to it and applies the incremental changes to a copy of data. A data synchronizer transfers incremental changes to a data collector. An agent controls the synchronization process by making a connection between a data collector and a data synchronizer and then directing the data synchronizer to transfer data to the data collector. If bidirectional data flow is necessary to achieve synchronization between two copies of data, a one-way data flow path is established first in one direction and after all incremental changes have been passed in that direction, a data flow path is established in the opposite direction to pass incremental changes in the opposite direction.
18 Claims, 7 Drawing Sheets
