With the integration of different formerly isolated information systems, such as Hospital Information System (HIS). Radiology Information System (RIS), Picture Archiving and Communication System (PACS) and modalities, we evolve towards an architecture of distributed information processing in radiology, the data being stored in distributed databases. The frontier between the cooperative information systems becomes more subtle than in the past, and it seems more convenient to distinguish the different computer functionalities or services used in radiology than to detail the functions of RIS and PACS. This paper opens with a description of the different computer services used in radiology and how they relate one to another. It also shows how these functionalities could be integrated within a global Radiology Information and Archiving System. Finally, it shows the degree of systems interconnection that can be achieved presently, using the PACS-RIS installation at the University Hospital of Freiburg as an example.