https://www.ccs.neu.edu/home/turon/reagents.pdf Turon, "Reagents: Expressing and Composing Fine-grained Concurrency"
Underlying the shared state/message passing duality is a deeper one: Isolation versus Interaction. Operations on shared state are generally required to be atomic, which means in particular that they are isolated from one another; concurrent shared-state operations appear to be linearizable into a series of nonoverlapping, sequential operations. Synchronous message passing is just the opposite: rather than appearing to not overlap, sends and receives are required to overlap. Fine-grained concurrent operations straddle these two extremes, appearing to be isolated while internally tolerating (or exploiting) interaction.
Underlying the shared state/message passing duality is a deeper one: Isolation versus Interaction. Operations on shared state are generally required to be atomic, which means in particular that they are isolated from one another; concurrent shared-state operations appear to be linearizable into a series of nonoverlapping, sequential operations. Synchronous message passing is just the opposite: rather than appearing to not overlap, sends and receives are required to overlap. Fine-grained concurrent operations straddle these two extremes, appearing to be isolated while internally tolerating (or exploiting) interaction.