|75||77||A second key design paradigm used in openEHR is that of separation of responsibilities within the computing environment. Complex domains are only tractable if the functionality is first partitioned into broad areas of interest, i.e. into a "system of systems" . This principle has been understood in computer science for a long time under the rubrics "low coupling", "encapsulation" and "componentisation", and has resulted in highly successful frameworks and standards, including the OMG's CORBA specifications and the explosion of object-oriented languages, libraries and frameworks. Each area of functionality forms a focal point for a set of models formally describing that area, which, taken together usually correspond to a distinct information system or service.