Use of ROOM in the design of data-acquisition software components

<P>Presentation made at the Real Time Conference, Santa Fe, New Mexico 14-18 June 1999<P>The Event Builder and Distribution System (EBDS) is a component of the data-acquisition architecture of the ALICE experiment at CERN. The purpose of the EBDS is to dispatch the sub-events originated in the detector front-end electronics to the processors of the Event Filter Farm, where the full events are assembled.<P>For the design of the EBDS, we use the Real-time Object-Oriented Modelling method (ROOM), which was chosen because of its powerful modelling paradigm, well suited to this type of application. The use of ROOM is aided by the ObecTime Developer tool set, which fully supports the method and covers all the aspects of the development cycle, from analysis to code generation. Fast prototyping and simulation bring a new perspective to the designer, who can advance by gradual refinements.<P>We describe how ROOM has been used to design a model of both the EBDS and its environment, and the results obtained from the simulation. We also review the experience acquired with ROOM and the ObjecTime tool, and indicate what benefits and obstacles we encountered.<P>