A distributed collaborative application (DCA) is a set of programs that communicate with each other to let users work together on shared information. Most often, the set of programs is multiple copies of the same code running on different machines. Each of these programs is called a DCA client. DCA clients accept user input to drive updates to shared state, then propagate updates to other collaborating clients.
A simple example of a distributed collaborative application is a shared whiteboard. Multiple users running client software contribute lines and shapes to form a single picture. In addition, users can make changes to the existing lines and shapes. In this simple example we see interaction between the user and the client application, and collaboration between users who can be located anywhere on the Web. Underlying the visuals of the shared whiteboard at each client application is some state representing that client's view of the picture. This thesis is concerned with the system infrastructure for managing and updating the shared state.