Communication between Ada programs in DIADEM
Colin Atkinson, Stephen J. Goldsack · 1988
It has been recognized for some time that Ada is not well designed for the purpose of programming networks of loosely-coupled processors, and numerous projects have been set up to find a solution. The DIADEM project had the particular goal of constructing flexible Ada programs that could be executed in a range of distributed systems, including, as a limiting case, a centralized uniprocessor. To this end a technique was developed by which the Ada rendezvous could be used as a remote communication mechanism, supported in a highly portable way on a range of different network architectures and communication systems. This was achieved by the definition of a special package providing a “standard interface” to the transport layer services of the host communication system. After outlining the basic principles of the DIADEM approach, and describing the first prototype implementation of the communication mechanism, this paper discusses how a standard interface similar to that used in DIADEM could provide an efficient, yet portable, technique for supporting remote communication in time-critical (hard) real-time, distributed systems.