The rationale of an environment for real-time software

Some core ideas that lead to the definition of an environment for real-time systems are discussed. It is explained how integration, flexibility, and validation support can be achieved by using a suitable formalism as a hidden underlying kernel for the environment. The kernel formal notation proposed (called environment relationship nets, or ER nets) is an extension of Petri nets where tokens are not anonymous. Rather, they are environments, i.e. mappings between variables and values. The use of the kernel model for supporting the development cycle is described, and the flexibility of the model which can support a wide set of views at different levels of abstraction and for different kinds of users at the same level is shown. The problems connected with the quality assurances of the system being developed are also discussed