ENSURING DATA AVAILABILITY, RELIABILITY AND QUALITY ON COMPUTER SYSTEM FOR CONTROL OF LARGE "ARIANE" TEST BENCHES

Abstract

Computer systems for large ESA test benches have very distinctive characteristics. One of their essential features is, of course, that the individual sub processes complete their tasks quickly. But next to speed, determinism is of equal significance. It means, for example, that redline conditions are monitored in exactly the given cycle and that command sequences are reproducibly executed at exactly the defined times in order to make the workflows at the test bench run the way the physical and chemical processes demand it. The actual capturing of data belongs under this kind of subtasks and usually realtime operating systems are employed to accomplish them. Other jobs that run in parallel, like data distribution, storage and visualization, are done on customary computer systems, which are better suited for this kind of application. Quality requirements put on those computer systems are really high as the test results of past decades must be kept comparable. So, transparency and reproducibility are essential issues to be safeguarded for every test executed. The performance standards of the systems also show in the availability of the entire hardware and software components throughout the entire year and in the guarantee that no test data can be manipulated or even lost. It needs a special hardware and software design to afford such guarantees as all data stream paths, e.g. from the sensors or command/event interfaces all the way down to the archive file, need to be set up safely and probably even redundantly. This safety and, with it, the certainty that the entire digitalized data are fully available at all times is ensured by different internal layers of hardware and software functions. Some of those functions are based on standard technology and adapted for the specific purpose while others are specially tailored for a certain application scenario. The presentation goes into the details of such hardware and software functions as well as the intrinsic design principles.