Statecharts supervision models for soft real-time systems

Developing a reliable software system is a major requirement today as it is mainly used for critical applications. Applications such as automatic flight control, banking, and telephone switching demand safety and real-time features. In such an environment, the occurrence of a failure may result in damage to the company´s reputation, and even catastrophic economic consequences. Another issue that must be addressed is low cost development. This paper presents the software supervision paradigm as a means to improve software reliability during the operational stage of a real-time system, specifically a PBX (Private Branch eXchange). As well, the use of Statecharts for specifying the realtime supervisor is advocated, and the supervision model for the PBX is given. Benefits of this approach are discussed throughout the paper