Notes on Concurrency Control in Groupware

These brief notes explore the requirements and design issues surrounding concurrency control in groupware – software with which several users, often geographically separated, collaborate on a shared task such as document writing. The next section gives an overview of groupware. We then give requirements and design issues, and go on to discuss how traditional concurrency control techniques such as database transactions are usually inappropriate for groupware, and describe and discuss alternatives. Finally, we suggest some categorisations of the ways in which users receive information about shared objects and the ways in which they interact in shared tasks.