Emulation of an Event Builder using the ATM Local Area Network of the RCNP Institute

The computer network at the Research Center for Nuclear Physics (RCNP), University of Osaka, has been rebuilt recently using state-of-the-art multi-processor servers and workstations linked by an ATM Local Area Network. This system has been used to emulate a down-sized version of a typical Trigger/Data Acquisition system and event builder as foreseen in future High Energy Physics experiments. The testbed comprises up to 25 computers representing a total of over 50 processors interconnected via the ATM network of the laboratory. We describe the system and measure the real-time performance of the various components. We present a comparison of ATM hardware and software from different vendors. The performance of the full-size testbed is presented and the issues that have been identified are discussed in view of building larger systems.