The appendix defines the data model used throughout the book and describes what can best be called an algorithmic design specification, that is, the functional and graphical characterization of an algorithm, chosen so that it can be translated to a computer architecture (be it in soft- or in hardware). We follow hereby a powerful “data flow model” that generalizes the classical signal flow graphs and that can be further formalized to generate the information necessary for the subsequent computer system design at the architectural level (i.e., the assignment of operations, data transfer and memory usage). The model provides for a natural link between mathematical operations and architectural representations. It is, at the same token, well adapted to the generation of parallel processing architectures.

The world of digital commerce is relatively new. It is a by-product of an information technology revolution that started with the invention of the integrated circuit, carried forward with advances in computing and unleashed with the creation of the internet. Digital commerce is familiar in some respects and dramatically different in others from the world of trade that preceded it. It poses special problems of privacy, unwanted communication, and new kinds of competition, stemming from the flow of data across borders. It gave rise to the need to devise rules for its nurture and management. It makes the most sense for the rules to be global, as without interference from governments, e-commerce is global. It creates opportunities as never experienced before for innovation and for individual and small business involvement in international commerce. This is the story of the evolution of the process of rule-making in the age of digital commerce.