Abstract: The disclosure describes a system that allows a system designer to build a virtual prototype before development of the actual components of a hardware/software system begins. The virtual prototype includes both the software and hardware components of the system being designed. The components are created from a limited set of design symbols. The symbols are placed in a design window and connected. In determining what symbols and connections to use, the designer obtains the functional requirements for the system being designed. The designer then generates environment components and boundary components that describe the interfaces to the system. Using active signal processing threads, the designer generates control components and entity components, and defines their interaction. The prototype is then simulated and the results of the simulation analyzed. The process is iterated with components added, deleted and connected until the design meets system behavior expectations.