Flexible support for application-sharing architecture

Current application-sharing systems support a single architecture for all collaborations, though different systems support different architectures. We have developed a system that supports a wide range of architectural mappings, which include, to the best of our knowledge, all of the existing architectures defined So far including the centralized, replicated, and hybrid architectures. Instead of being bound to a specific I/O protocol such as the X protocol, it is based on a simple abstract I/O protocol to which specific I/O protocols must be mapped by client-supplied code. We have used the system to perform experiments that compare the performance of the centralized and replicated architectures. Our experiments show that the choice of the architecture depends on the computers used by the collaborators, the speed of the connections between the computers, and the cost of the operations performed by the shared application Under some conditions the centralized architecture gives better performance, while under others the replicated architecture gives better performance. Our results contradict the popular belief that the replicated architecture always gives better performance, and show the need for supporting both architectures in a system.