Abstract: To facilitate the carrying out of a range of different types of management task in a computer system (such as fault diagnosis and service installation), declarative models (22) are constructed of the various services provided by the system (10-13). These models (22) specify the requirements that need to be met for the corresponding service to be available. These requirements are set out in terms of the system entities that need to be present and the inter-relationships of these entities. In addition, each management task is specified in a corresponding task program (21) in terms of general inferencing operations that can be performed on any of the models. Execution of a particular management task involves carrying out inferencing operations on the appropriate service model (22) in accordance with the task program (21) for the management task under consideration.