Issues of synchrony, asynchrony, and synchronization, arise frequently in designing embedded systems from
components, like everyone I knew this for quite a long time. But it is only recently that it went aware of the diversity of such issues, depending on the context. The aim of this paper is to show and explain this diversity by looking at three areas where systems design is of interest, namely: 1/ building software or hardware architectures composed of
components interacting asynchronously, 2/ synchronous hardware design from IP's, and 3/ designing distributed real-time control systems. A large part of this paper relies on other people's work, I indicate appropriate references in
each case.