4The requirements of an application domain shall drive the design of the system. They describe what the system is supposed to do. The introduction to data acquisition in high energy physics outlined a variety of different aspects that lead to a collection of requirements for the software infrastructure. They can be split into four dimensions: speed, scale, system management and dependability. In this thesis I emphasise speed in object communication and management of processing farms. Scale is an issue that has to be included in both observations. The dependability requirement is briefly outlined in this chapter.