From information systems to knowledge systems

We consider the evolution of information systems towards sophisticated knowledge systems. Investigating the key concepts for information and knowledge systems from a logical point of view, we show that the two most fundamental operations are inference (query answering) and update (‘data manipulation’). They have to be available in every system. Advanced information systems may allow for negative, disjunctive and uncertain information. Even more advanced systems (which might be no longer called information but knowledge systems) will allow for sophisticated reasoning services, such as deductive query answering, active input processing, representing actions, generating explanations, diagnoses and plans.