CRISTAL is a distributed scientific workflow system used in the manufacturing and production phases of HEP experiment construction at CERN. The CRISTAL project has studied the use of a description driven approach, using meta-modelling techniques, to manage the evolving needs of a large physics community. The next generation CRISTAL vision is to build architecture based on co-operating distributed production managers. The overall production model, plan and production policies are described in a central repository. These production requirements and constraints are pushed out to the production managers using publish-subscribe mechanisms. The distributed production managers have knowledge and are able to build certain components including system elements capable of performing computations and writing data based on previous data collected by the system. The elements are user defined, and the algorithms are stored in so called "User Code". This paper discusses the next s!
tage in the design and behaviour of these elements, concentrating on the specification, development, testing, deployment and versioning of these components. The first part of the paper will discuss the concepts of components and component architectures. A following section explains how components are used and versioned within the new system. The final part of the paper will describe how the workflow concept can help solve the problems of scheduling and deployment of the different versions of User Code components.

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