Evolution of real time computer systems for test benches

This paper covers the development of computer systems during the course of the last 25 years for the Ariane project ESA test benches P5, P4.1 and P4.2. On these test benches the DLR-teams are testing and qualifying the rocket engines "Vulcain2", "Vinci" and "Aestus". Twenty-five years ago the criteria for specification and procurement for test bench computer systems was very different from today. Mostly the systems were custom made and very often the component interfaces had to be developed specifically for the site. Systems offering high reliability, that would run 24 hours a day and on 365 days a year were very much the exception