Implementations and extensions of the conversation concept

Conversations were proposed as a means of organizing fault tolerance by coordinated backward recovery in a set of communicating processes, avoiding the domino effect and allowing diversity in the retries. The general concept of conversations is susceptible to many different detailed implementations. We review and discuss the problems of implementation and of practical use of conversations, comparing and generalizing the solutions offered in the different existing proposals, and suggesting some useful extensions. We discuss limits to the complexity of implementations that can be exploited in practice, and to the applications that can be programmed using the conversation scheme.