MECDAS-a distributed data acquisition system for experiments at MAMI

For coincidence experiments with the three-spectrometer setup at MAMI an experiment control and data acquisition system has been built and was put successfully into final operation in 1992. MECDAS is designed as a distributed system using communication via Ethernet and optical links. At the front end, VMEbus systems are used for real time purposes and direct hardware access via CAMAC, Fastbus or VMEbus. RISC workstations running UNIX are used for monitoring, data archiving and online and offline analysis of the experiment. MECDAS consists of several fixed programs and libraries, but large parts of readout and analysis can be configured by the user. Experiment specific configuration files are used to generate efficient and powerful code well adapted to special problems without additional programming. The experiment description is added to the raw or partially analyzed data to get self-descriptive data files