Message passing in Erlang is asynchronous in the sense that messages can be queued, but from the point of view of the process receiving message is synchronous f

Message passing in Erlang is asynchronous in the sense that messages can be queued, but from the point of view of the process receiving message is synchronous function call that happens on well defined place in the process, in contrast to truly asynchronous message receipt which would interrupt the process/start new thread at arbitrary places in code, which is the model used by some microkernels and similar systems (this can be emulated in userspace by starting background thread which runs some event loop, for example SDL, and optionally ALSA, uses this pattern for audio I/O).