OBJECT-ORIENTED AND FUNCTIONAL SOFTWARE-DESIGN FOR DISTRIBUTED REAL-TIME SYSTEMS

Real-time systems in applications like command, control, communication s and intelligence require complex distributed systems with many inter acting software components, heterogeneous processing systems and shari ng resources. These systems should satisfy not only the functional req uirements of application software, but also the specified timing const raints on the execution of the software, despite faults and failures. In addition, parallelism needs to be expressed in the design of such s ystems and exploited on the target distributed computing systems. In t his paper, an approach to software design for distributed real-time co mputing systems, based on the PROOF computation model which integrates object-oriented and functional paradigms, is presented. To support ad aptability of the software system to a predictably changing environmen t, our approach supports multi-versions of a method definition, synchr onous communication within objects, asynchronous communication among o bjects, encapsulation of timing constraints in objects and expressing parallelism in object-level and method-level. Our design approach cons ists of the high-level object-oriented design and object design phases . Our design approach is illustrated with a hypothetical chemical plan t simulation system.