A Web Solution to Concurrency Awareness in Shared Data Spaces

Computer Supported Collaborative Work (CSCW) must present a shared workspace to co-operating users. This implies having a suitable engine at the client side which permits setting a focus on the shared data. Any concurrent activities of other users which happen to stretch into this viewport must also be made visible. Furthermore, the client must provide mechanisms for moving among the data (objects) and for making one’s presence known. On the server side, a globally consistent state of the data must be maintained through an extended transaction concept. Here we present a description of a very compact, yet extensible solution to this task. It involves a standard Web browser with a small applet (less than 3 KB) as interface generator, and an object-relational database engine as server. The server uses a Tcl-based navigational language and drives the interfaces for the clients via stream socket connections.