Modeling of distributed real-time systems in DisCo

We describe adding of metric real time to joint actions, and to the Disco specifcation language and toot that are based on them. No new concepts or constructs are needed: time is represented by variables in objects, and action durations are given by action parameters. Thus, we can reason about real-time properties in the same way as about other properties. The scheduling model is unrestricted in the sense that every logically possible computation gets some scheduling. This is more general than maximal parallelism, and the properties proved under it are less sensitive to small changes in timing. Since real time is handled by existing Disco constructs, the tool with its execution capabilities can be used to simulate and animate also realtime properties of specifications.