Information systems: Modelling, sequencing and transformations

Specification and design of an information system conventionally starts from consideration of the system function. This paper argues that consideration may more properly be given first to the system as a model of the reality with which it is concerned, the function being subsequently superimposed on the model.

The form of model proposed is a network of sequential processes communicating by serial data streams. Such a model permits a clear representation of change or activity over time, and it also prevents over-specification of sequencing by separating problem-oriented from solution-oriented sequencing constraints. The model, however, cannot be efficiently executed on uniprocessor hardware without transformation. Some relevant kinds of transformation are mentioned, and the derivation, by means of them, of conventional information system configurations from the proposed model.