Teaching graduate students how to develop hard real-time Ada software for embedded systems is a challenging task. We successfully used Ada in a series of software engineering courses to teach graduate students the charac of hard real-time software and fundamental skills to develop and validate complex systems and timing re through software prototypes of the systems. A research tool, called CAPS (Computer Aided Prototype System), was used by the student software designers to construct software prototypes based on the require of the system as well as to automatically generate Ada code interconnecting reusable modules. The approach greatly stimulated the students' interest and helped them to gain first hand experiences in developing hard real-time systems.