Experiences at HERA with the H1 data acquisition system

The recently commissioned HERA collider provides a significant pointer to the problems that have to be surmounted in data acquisition systems at the next generation of hadron machines. With bunch crossings, between 30 GeV electrons and 820 GeV protons, 96 nanoseconds apart, the H1 experiment illustrates the application of sophisticated pipelining solutions in the readout of several hundred thousand electronic channels. A modular, multiprocessor design structure emphasis the architectural concepts necessary to cope with large data throughput and yet remain flexible enough to exploit ongoing technological advances in both hardware and software. The range of techniques implemented will be surveyed, covering various digitisation solutions at the front-end through to embedded microprocessor arrays in standard busses controlled by graphics-based stations executing object- orientated code. The experiences gained in developing such a system are also discussed. (orig.)