Object-oriented real-time system analysis and design issues

Abstract

The organizers were successful in enlisting participants from a number of organizations around the world. Participants were selected based on a position paper related to the issues listed in the OOPSLA'93 Advance Program. Those submitting papers which were not selected for discussion during the workshop were invited to be observers during the workshop. There were nine participants, which made presentations related to their position papers, and 18 observers present at the workshop. Activities The agenda for this workshop was designed to allow position presentations to be followed by a discussion period related to the presentation. A transcript of the workshop is being developed and should be available in the not-too-distant future. The first two papers were presented by John Gilbert and Bob Wilhelm of Objective Software. John Gilbert's presentation discussed many of the historical aspects of real-time systems. He also discussed the various types of real-time systems: hard real-time, continuous stream, distributed real-time, and deadline driven real-time. There was a challenge from another participant over a comment in his paper stating that, " All but truly hard real-time systems benefit from the object-oriented approach. " He indicated that objects can play a significant role in the organization and structuring of real-time systems. Objects do not liberate machine cycles. On the contrary, they consume them. Bob Wilhelm discussed the structural and architectural implications of object-oriented systems. Much of his presentation dealt with concurrent objects with multiple threads of execution and various models for synchronizing message passing. He indicated the need for concurrency arises in 00 systems in order to effectively model the real world. l Inter-object concurrency represents the natural ability of real-world entities to act independently and concurrently with each other. l Intra-object concurrency represents the natural ability of real-world entities to exhibit multiple behaviors simultaneously. The next three papers were presented by Paul Ward of Software Development Concepts, Bo Sanden from George Mason University, and Francois Terrier of the French Atomic Energy Commission. They presented three development notions. Paul Ward made a brief comment about the need for effective handling of the complexity of real-time systems and led a discussion for the remainder of his time. He suggested that developers should not worry about active or passive objects and discussed a virtual device object which interacts with other objects via a highly abstracted, standardized interface. Such an object encapsulates two component objects: the first is an interface to the …