Abstract
RealSpec is a declarative executable language for the prototyping of concurrent and real-time systems based on a dataflow functional model. RealSpec is developed on top of Lucid dataflow programming language by enhancing Lucid with features for real-time systems. This paper provides basic RealSpec language constructs for modeling concurrent processes, multithreading, and resource modeling. The producer consumer example is used to demonstrate the applicability of these language features.