Mac an Airchinnigh, M2014-07-312014-07-3119841467-8659https://doi.org/10.1111/j.1467-8659.1984.tb00060.xOne of the most important uses of (interactive) computer graphics is as one of the tools available to a User Interface Management System (UIMS) for a variety of user-computer environments (UCE). Typical UCEs in vogue are Programming Support Environments (PSE), Expert System Builders (ESB), Office Automation systems (OAS). This paper concentrates on the conceptual relationship that exists between the users on the one hand and computer systems on the other. Such relationships are to be seen in the context of specific application domains. The two standards, GKS and Ada, are chosen to be the background against which the argument for a Software Methodology based on the Abstract Data Type approach, is presented. This has significant implications for a GKS binding to Ada and the development of GKS application software written in Ada. A collection of colour models is considered in detail.Ada(R) is a registered trademark of the U.S. Government, Ada Joint Program Office.10.1111/j.1467-8659.1984.tb00060.x153-165