The specification, development and use of distributed information systems is an important research area with many practical applications. Examples for existing such systems are those owned by banks, airlines or governments. Moreover, the explosive growth of the Internet is evidence that a global information structure is developing, and expansion in the use of large distributed information systems can be predicted.
Information systems are reactive systems.
Basic notions of program correctness do not apply, and techniques for designing transformational systems do not easily carry over to reactive systems. However, existing products can already cope successfully with reasonably complex systems in practice. Formal methods from logic, algebra and process theory have been successfully applied, for instance in query and transaction processing, but they are not in general standard engineering practice yet. Distributed reactive systems are still an order of magnitude more complex and difficult to specify, analyse, implement and reconfigure. They are not well understood, and methods for designing, implementing and reengineering them have not yet reached a level of mature and sound engineering practice.