ADL: A Graphical Design Language
for Real-time Parallel Applications
Maarten R. van Steen1;2
Armand ten Dam2
1 Erasmus University Rotterdam
Department of Computer Science
POB 1738, 3000 DR, Rotterdam
2 TNO Institute of Applied Physics
POB 155, 2600 AD, Delft
Designing parallel applications is generally experienced as a tedious and difficult task, especially when hard real-time performance requirements have to be met. This paper discusses on-going work concerning the construction of a Design Entry System which supports the design phase of parallel real-time industrial application development. In particular, in this paper we pay attention to the development and implementation of a graphical Application Design Language. The work is part of the ESPRIT project Hamlet which focuses on industrial application of transputer-based systems for commercially strategic real-time applications.
Over the last twenty-five years concurrency has become one of the most active areas of research in computer science. Concurrent models have been widely applied in the design of operating systems and databases, and as efficient implementations of high-level concurrent languages became available, software that was originally coded in an assembly language could now be developed using high-level language constructs yielding well-structured, efficient, and portable implementations.
As insight in the behavior of concurrent models grew, focus has gradually shifted from the problem of developing programs that behave in a well-defined manner to that of developing programs that exploit parallelism to improve overall efficiency. This shift of focus has brought us, somewhat surprisingly, to a stage comparable to the first stages of research in concurrency issues. At the moment, parallel applications are generally written in a highly machine-dependent manner and often violate basic rules of well-structured software in order to retain efficiency .