Betriebssysteme und Verteilte Systeme
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Programming embedded real time systems is a diffcult task. The reason is, that programmers have no knowledge about the timing behaviour of the system during development time. The object of the project Artemis is a development tool, which dispose the timing behaviour of code fragments in relation of the stimuli to the programmer. Artemis is a abbrevation of "Analysis of real time systems in an embedded environment with an interactive system". The term stimuli stand for the interface between program and the system environment like global variables and sensors.
The main proplem in the prediction of execution time is the prediction of loop bounds. State of the art in calculation of timing properties are annotations in the source code to determine the loop bounds. This approach leads in a pessimistic prediction of the worst case execution time (WCET). To obtain a better prediction of the WCET, the influence of stimuli to the WCET must be take into account. In Artemis a symbolic execution time of code fragments will be derive from the semantik of the fragment. With the symbolic representation of the execution time we can calculate the WCET or the execution time for a set of stimuli. It is also feasible, to calculate a subset of stimuli, that will not hold a deadline. With these subset of stimuli we can simulate or test the system to examine the behaviour of the system in a critical situation.
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Last change: 1999/11/24 Olaf Maibaum