Automatic generation of scheduling and communication code in real-time parallel programs

Inter-process communication and scheduling are notorious problem areas in the design of real-time systems. Using CASE tools, the system design phase will in general result in a system description in the form of parallel processes. Manual allocation of these processes to processors may result in error prone and/or slow communication code. Scheduling of the processes, necessary to meet timing constraints, is also a tedious task that takes many iterations. The described design tools result in code that is comparable in quality and performance with expert manual realization. Many network layers have been implemented to relieve the user from the low-level programming of communication software. However, the increase in user-friendliness is usually paid with performance degradation. The proposed approach combines user-friendliness with high performance by generating communication software that is tailor-made for the application. A similar approach is followed with the scheduling software. Schedulers in the form of a built-in a kernel are available all the time and cause overhead all the time. The proposed preprocessor tool generates scheduling software after analyzing the timing requirements of the particular application. This results in simple code for simple timing requirements and more complicated code for complex timing requirements. The tools have been implemented in Occam for use on a transputer. However, the results are valid for any distributed memory machine

On issues of constructing an exception handling mechanism for CSP-based process-oriented concurrent software

This paper discusses issues, possibilities and existing approaches for fitting an exception handling mechanism (EHM) in CSP-based process-oriented software architectures. After giving a survey on properties desired for a concurrent EHM, specific problems and a few principal ideas for including exception handling facilities in CSP-designs are discussed. As one of the CSP-based frameworks for concurrent software, we extend CT (Communicating Threads) library with the exception handling facilities. The extensions result in two different EHM models whose compliance with the most important demands of concurrent EHMs (handling simultaneous exceptions, the mechanism formalization and efficient implementation) are observed