Modelling microprocessor farms for SSC (Superconducting Super Collider) data acquisition

Data acquisition, involving both data collection and accompanying filtering, is a crucial part of an SSC experiment. The extreme demands on the acquisition system for I/O bandwidth and real-time computation capability that makes irrecoverable event selections requires that the system operation be well designed and fully understood. Modelling is a valuable and perhaps necessary tool for a successful design of such complex systems. As a demonstration of the modelling process we have made a few studies of simple systems consisting of a large number of microprocessors arranged in a ''farm'', a system in which each event is routed from the digitization/readout crates directly to a single microprocessor, one of a large parallel array, which performs the complete software event filter on that event. Subsequent events are transferred in turn to other processor nodes which are idle. The results of our crude simulations agree with the expected performance of such farms, and suggest that realistic modelling of SSC acquisitions will be important. 3 figs.