Building a web service technology-based factory IT-landscape using WebObjects
Poster at WWDC 2006, August 7-11, 2006, San Francisco, USA
Introduction The IT architecture that is operated in many semiconductor factories today has been growing over the years. As the requirements for tracking, data acquisition, production control, etc. became more demanding, more and more applications were added. Thereby, the complexity of the IT landscape increased significantly, especially due to the large number of more or less documented dependencies between several applications. Maintenance and management of these environments becomes more and more difficult. At the same time, the importance of software on the shop floor has been increasing. Production lines cannot be operated anymore if the software is not available. Software issues can easily delay the ramp phase of a new production line or be a limiting factor for further development of existing factories. On the other hand side, the market situation changes frequently and requires companies to adapt to changes very quickly. An agile IT landscape is therefore a prerequisite for success. The Service Oriented Architecture (SOA) paradigm is currently considered to be a promising approach to solve such issues across many industries. Although many expectations raised by the current hype will probably not be met' the same was true for the introduction of the object oriented paradigm' there are several concepts that are worthwhile to be investigated in more detail. These concepts might change the way semiconductor factories are operated today and pave the way towards more agility. Several of these concepts have therefore been evaluated and implemented in the context of a European research project. The results are discussed in this paper. The Approach For the research project it was decided to implement a service oriented architecture based on Web service technologies with Apple WebObjects. This includes XML technologies, various communication protocols (e.g. HTTP), message specifications (SOAP and its extensions), technologies to describe (WSDL), to discover (e.g. UDDI), to secure and to manage Web services and others to perform additional tasks. There are major advantages in using the Web service technologies compared to others, such as CORBA based solutions or proprietary solutions. The Web service technologies have been broadly accepted across all industries' many commercial applications offer Web service interfaces. Open source as well as commercial implementations and toolkits are available on the market and provide a basis to build products upon. Furthermore, a significant amount of experience using these technologies has been collected over the last years and can be taken into account for the development. In order to evaluate and demonstrate the potential of a Web service technology based SOA approach for the production IT environment beyond the capabilities provided by Interface A and B (SEMI Standard) we developed the architecture for an SOA-based MES system (Manufacturing Execution System). Although the results are mainly discussed in the MES scope they can be transferred to other areas of the production IT landscape. The Prototype The architecture has been realized in the form of a proof-of-concept implementation based on off-the-shelf frameworks as far as possible, including Apple's WebObjects application server, EOF object/relational mapping framework, Web service tool-kits, cryptography toolkits, etc. In addition we developed framework components to enable version control, release management and authentication/authorization that are shared across the system. The collection of services realizing the functionality for the MES domain was built on top of them, including services for product and process specification, WIP tracking, resource management, job management, etc. Architecture Potentials and Issues Based on the architectural concept, its implementation and its evaluation we discuss pros, cons and potentials for a production IT landscape which is build upon Web service technologies. Among other criteria we address agility, performance, scalability and manageability. New Areas for Standardization A major concern of Web services is interoperability. While the Web service related standards lay the foundation for interoperability between Web services, additional domain related standards enable exchangeability of service implementations. We give hints where additional standards might provide benefits for the semiconductor industry. Conclusion Based on the experience from our MES project we show the potential of a Web service technology based factory IT landscape.