For Asynchronous Systems R.J.A. Macedo University of Newcastle upon Tyne.
Further complications arise if processes belong to multiple groups.
We show that Causal Blocks provide a consise method for deducing ordering relationships between messages exchanged by processes of a group, resulting in simple methods for dealing with multiple groups. We also present causal order protocols with different trade-offs between message space overhead and speed of message delivery. Furthermore, we show how the Causal Blocks representation can be used to easily deduce and maintain reliability information. The total order protocol, together with a novel flow control mechanism, has been implemented over a set of networked Unix workstations, and experiments carried out to analyse its performance in varied group configurations.