The data acquisition system of the RFX experiment

The paper describes the experience gained in the development and maintenance of the data acquisition system for the RFX nuclear fusion experiment. The design of the system core started in 1987 and the system was ready at the beginning of the machine operation in late 1991. Since the early design stage it was clear that a careful definition of the system architecture was crucial for allowing the system to cope with the expected improvement in the hardware performance. Not all the initial design choices proved successful for this purpose. In the paper the (positive or negative) consequences of the main design choices of the system are reported.