Architectures for Synchronous Groupware

Synchronous groupware systems allow physically separated users to interact with one another and with shared computational objects in real time. Such systems are problematic to build since their user interfaces must support multiple, concurrent users, and both their application logic and their user interfaces must be distributed across multiple platforms. This survey explores the range of software architectures that have been proposed to solve this problem. The presentation includes three distinct architectural views: reference models, which divide complete systems into named functional elements and specify data ow between those elements; architectural styles, which prescribe component and connector types and their allowed patterns of interaction; and distribution architectures, which represent the distribution of system functionality across connected computing platforms. The distribution architectures are presented using a new descriptive framework called Interlace. The architectural presentation is complemented by a brief overview of consistency maintenance mechanisms for groupware.