Group coordination in participant systems

Participant systems are computer systems that support persons working collaboratively. They must provide two classes of service, the first being protocols that coordinate the cohesive behaviour of individuals in a group, and the second being mechanisms for sharing applications among the group. Differences between participant systems can be found in a number of fundamental distinctions: the use of voice, support of face-to-face or physically distributed groups, asynchronous versus present-time communications, the support of shared applications, use by large or small groups, and central or distributed implementations. Cantata is a text and shared-whiteboard participant system for physically distributed groups that operates in the present-time. It shares applications among small groups in a distributed implementation on Macintosh computers in an Appletalk network. The features of Cantata that facilitate group coordination and applications sharing are described. These include: multiple scrollable windows, simultaneous broadcast of messages, explicit topic reference, time-synchronized playback of interactions, a focus of attention mechanism, and a built-in dedicated applications, the participant construct system PCS, used for knowledge elicitation and consensus achieving in groups