Conflict control locking in distributed cooperative graphics editors

Communication latency presents a major challenge to achieving high responsiveness for Internet based cooperative editing systems. The authors propose conflict control locking (post-locking) schemes for conflict resolution in real time object based cooperative graphics editors. With these schemes, no locking request is needed before applying an editing operation to an object, instead, a lock will automatically be generated by the system if a conflict occurs. Lock ownership assigning rules are devised for the schemes. With a specific post-locking approach, algorithms and implementation techniques such as lock synchronisation detection, voting, and group intention realisation, are discussed in detail.