d A KBS is any computer system or subsystem which processes emerging is Schlaer-Mellor's OOA/OOSD which is an extension of the 1989 OOD from Schlaer-Mellor, with others being produced. 'knowledge'. 2. Knowledge is a rich form of information, often stored by hu- Object oriented methods are particularly applicable for projects mans as expertise in some restricted domain, e.g. problem involving a large amount of data definition and manipulation al- solving skills such as medical diagnosis or resource scheduling. though their general applicability and usage is growing. It is often represented as facts, rules, concepts, assumptions, These methods are graphically based, relying on annotations to provide a more rigorous definition of the data or the software (method) associated with each object. Thus it is possible to combine Within this broad scope, it is possible to distinguish different types the use of a formal language with object oriented methods; the of KBS according to different criteria. For example, one may choose diagrammatic object oriented technique providing an accessible to distinguish systems according to the 'problem solving' task they front end to the underlying formalisms which need be understood perform or support; or one may wish to differentiate systems ac- only by the designer of the object. cording to the 'role' that they play in relation to other systems or One of the major advantages of an object oriented approach, apart people in a co-operative working environment. Another simple way from the fact that the objects are easily traceable back to real world is used below. Five types of KBS have been found to be appropriate objects and events, is that it encourages the system designers to for development using the KADS methods using the following partition concepts with minimal interdependencies and maximum classification: reuse. This approach enables large teams to work effectively together and as libraries of reusable software components are built Generic Systems. Systems which are designed to be