The system's response to these qualities is the result of structural trade-offs made and probably not documented by the original designers. Properties can be listed and discussed in an artifact such as a requirements document. However, if all properties were equally easy to achieve, the analysis of trade-offs and setting of priorities would be a simple task. It is not. The relative costs of different concerns, and the architectural alternatives that support these concerns, become more concrete when design begins.
Many influences are at work in the design of an architecture.
The realization of these influences will change depending on the environment in which the architecture i s required to perform. In any development effort, the requirements make explicit some of the desired properties of the final system. But the requirements specification only begins to tell the story. Failure to satisfy other constraints may render the system as worthless as if it functioned poorly.