The ZEUS Eventbuilder: experience with a distributed real-time parallel transputer system

The Eventbuilder of the ZEUS experiment is a real-time parallel data formatting and transport system. It combines data flows originating from various detector components and transfers them to the third level trigger processor farm. The Eventbuilder is based on an asynchronous packet-switching transputer network and uses transputer links for bulk data transfer. A high-speed 64×64 custom made crossbar switch allows dynamic linking of any detector component to any branch of third level processor nodes, offering a bandwidth of more than 24 MB/s over a distance of 100 m. Experience gained in operating a transputer network, constructing transputer specific hardware, and developing parallel software is promising. Multi-transputer systems are easy-to-build, can be efficiently programmed in the common high-level language C, and are running stably and reliably