The Hamlet design entry system: an overview of ADL and its environment

Exploiting parallelism for industrial real-time applications has not received much attention compared to scientific applications. The available real-time design methods do not adequately address the issue of parallelism, resulting still in a strong need for low-level tools such as debuggers and monitors. This need illustrates that developing parallel real-time applications is indeed a difficult and tedious task. In this paper we show how problems can be alleviated if an approach is followed that allows for experimentation with designs and implementations. In particular, we discuss a development system that integrates design, implementation, execution, and analysis of real-time applications, putting emphasis on exploitation of parallelism. In the paper we primarily concentrate on the support for application *design*, as we feel that parallelism should essentially be addressed at this level

Prototyping real-time systems

The traditional software development paradigm, the waterfall life cycle model, is defective when used for developing real-time systems. This thesis puts forward an executable prototyping approach for the development of real-time systems. A prototyping system is proposed which uses ESML (Extended Systems Modelling Language) as a prototype specification language. The prototyping system advocates the translation of non-executable ESML specifications into executable LOOPN (Language of Object Oriented Petn Net) specifications so that ESML can be used as a graphical executable specification language for the prototyping of real-time systems. If the translation process is automatic then the user need not be aware of LOOPN. The ESML/LOOPN prototyping system defines an execution semantics for the ESML language in terms of LOOPN nets, a set of translation templates are supplied for the translation of ESML language specifications into LOOPN language specifications. The execution semantics are based on a set of execution rules (guidelines) which have been defined for ESML to allow prediction of the behaviour of ESML specifications over time. A C language program which can be run by the user as a prototype of the modelled system is generated automatically from the LOOPN specification. The ESML/LOOPN prototyping system has been applied to build an exploratory prototype of a typical real-time system, 1e the Fuel Subsystem of the Auxiliary Power Unit (APU), an avionic system used on the Boeing-737 airplane series