SIMDAQ-a system for modelling DAQ/trigger systems

The Atlas detector for the LHC accelerator at CERN requires a trigger and data acquisition (DAQ) system capable of handling bunch crossings every 25 ns. A three level trigger has been proposed. While the first level, which processes events synchronously, can be investigated analytically, the second level onwards, which processes events asynchronously, requires detailed modelling. SIMDAQ, a tool to model trigger and DAQ systems, is described in this paper, along with preliminary results from simulation studies of the Atlas trigger and DAQ system using SIMDAQ