A computational architecture for real-time systems

[摘要] ENGLISH ABSTRACT:The engineering of dependable real-time systems for mission critical applications is a resource intensiveand error prone process. Achieving dependability requires a general consensus on the correctness ofa system with regard to its intended function. For a consensus to be achieved, the properties of thesystem must be well understood which, in turn, requires consensus on a rigorously defined computationalarchitecture. There is currently no single agreed upon computational architecture at the application levelwhich can serve as a common denominator for the design and implementation of real-time systems. Itis the thesis of this dissertation that a rigorous computational architecture, applicable from design toimplementation, enables engineers to better understand software for real-time systems. To substantiatethis claim, the real-time data flow architecture RDF with its notation allowing the description of completesystems from design to implementation will be explored. Four distinct research areas for improvingthe engineering process of real-time systems are dealt with in the dissertation: 1) the developmentof an architecture for real-time systems being suitable for design and implementation in software andhardware, 2) the consolidation of a number of graphical languages into a graphical notation for functionalspecification, design and construction of real-time systems, 3) the development of a simple processorarchitecture for the execution of real-time applications, and 4) and the evaluation of the architecturein the framework of a microsatellite case study. In particular, the following original contributions aremade: 1) the firing semantics of data flow systems are expanded to include disjunctive firing semantics ina novel way in addition to the classical conjunctive firing semantics, 2) the inherent real-time data flowproperty, Le. that a receiving task must be ready to receive the next incoming message when it is sent,is extended to the synchronous data flow model, 3) a notation for describing all properties of real-timesystems is defined 'with the real-time data flow language RDF as base language, 4) two hardware processorarchitectures are introduced that offer one-to-one correspondence between design and implementationand, thus, reduce the semantic gap between design language and program execution, and 5) the classof systems that can be modelled with data flow architectures is shown to include control systems anddata flow systems. The language set and processor architecture were applied to certain aspects of theSUNSAT microsatellite project.

[发布机构] Stellenbosch University