Towards a New Approach to Tightly Coupled Document Collaboration

Currently document collaboration typically proceeds using tools such as CVS or vendor-specific Computer Supported Collaborative Work (CSCW) and Electronic Meeting (EM) messaging systems. Both regulate essentially asynchronous loosely coupled collaboration. The prime disadvantages of these technologies are that often documents are checked out or distributed in their entirety and that human interaction is needed in case of unresolvable conflicts. On the side of tightly coupled distributed collaborative work, emerging XML databases are employing database-type concurrency control techniques, but unfortunately tend to lock entire documents preventing simultaneous updates. XML-enabled relational databases have the same intrinsic problems, leading to the question if another way is possible. In this speculative short paper we describe a novel approach toward tightly coupled document collaboration, involving database-style synchronous client-server collaboration tailored to semi-structured documents. It is partly based on previous theoretic results which introduced path locks to control concurrency on semi-structured data. We also describe how clients may use a future communication protocol based on the path locks.