A Short Introduction to Synchronous Communication

The advent of multicore architectures is a good incentive to better understand base synchronization mechanisms. This paper, which can be considered as a simple introduction to the topic, presents (with a pedagogical flavor) the concept of rendezvous (also called interaction, synchronous communication, or logically instantaneous communication) and several implementations of it. This abstraction adds synchronization to communication, namely, it requires that, for a message to be sent by a process, the receiver has to be ready to receive it. From an external observer point view, the message transmission looks like instantaneous: the sending and the reception of a message appear as being a single event (and the sense of the communication could have been in the other direction). From an operational point of view, we have the following: for each pair of processes, the first process that wants to communicate - be it the sender or the receiver - has to. wait until the other process is ready to communicate.