The Instantiation of System Architectures

An implementation of a concept can be viewed as the content of that concept together with contentual context provided to instantiate the content for a specific domain. A number of design decisions need to be made in order to create such an implementation:

1. One of possibly many choices of content needs to be made. This content can be viewed as the "glue" that binds together the choices of contentual context.
2. Concepts need to be chosen for each contentual context parameter. In making each choice, conceptual context has to be provided by the content environment. If the content environment has inherited conceptual context, that context becomes part of the content environment, and can be "passed on" as conceptual context for these "lower level" concepts.

In a complex system, the concepts provided to instantiate either conceptual or contentual context themselves need to have an associated content in order for a system to be instantiated. This content has its own content environment and needs to be instantiated with contentual context. Thus the cycle repeats, until the only remaining context choices are those concepts provided by the Ada Abstract Machine and/or an available component library (In cases where run-time environment design decisions have to be made, the cycle is extended further).

As an example, consider a calculator algorithm whose content requires the contentual context of a Stack concept. That is, its content must have access to a Stack package to do its work. Furthermore, the Stack package is generic, requiring the conceptual context choice of base Element type in order to be instantiated. This base element type is provided by the content environment. In this case the element type is most likely some numeric type, either fixed by the calculator concept or provided as a generic parameter to that concept.

If a concept has not been completely instantiated with conceptual context, this results in a partially instantiated content environment, i.e., a generic architecture. Even if a concept has been completely instantiated with conceptual context, design decisions in the content might be deferred, again resulting in a generic architecture. These design decisions include the choice of both content and contentual context.