An overview of the Data Flow system for the NA48 experiment at CERN

The NA48 experiment at CERN is designed to measure the magnitude of direct CP-violation in the neutral kaon system. The experiment requires a Data Flow system which will run at up to 100 Mbytes/sec. Elements of the detector generate data which are presented to Optical Link Sources. Data arrive at the Data Merger which concatenates the various sub-events into a complete event. The data are then sent, via a HIPPI-link and a crossbar switch to one of several Alpha OSF/1 workstations for filtering, reconstruction and storage. Software applications control the Data Flow System include a Control Program which supervises the system, a Data Merger Controller Program which controls data merging and distribution and other tasks which supervise storage resources. This paper provides an overview of the hardware setup and the software tasks which control and monitor it. The current state of development of this system and results obtained during test beam running in June and September 1994 are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>