Control structure for systems analysis and design: a tool for defining the functional architecture of organizations and information systems

In recent years there has been a great deal of interest in methodologies for developing software that is reliable, maintainable and extensible. Since programs are the products of the software development process, it is natural that the early efforts to improve the quality of software were concentrated on the programming aspect of software development. However, it is clear today that no programming methodology can overcome the errors and problems incurred in the functional specification phase of software development. The complexity of the software specification task is well accepted but very few ideas for dealing with that complexity exist. A new approach is needed that enables the analyst to develop correct specifications that can be validated in terms of the information needs.The approach presented in this paper focuses on the problem definition for information systems that is based upon organization structure and functions. Social organizations are open systems as defined in general systems theory, and as such the functions of an organization may be analyzed in terms of a general model of open, living systems. The paper presents the application of an open system model to define the functional structure of organization subsystems and their interrelations that achieve the overall objectives of the organization.The open systems model is applied to define two dimensions of the problem, the resource flows and the control structure of the organization. Those dimensions define the functional hierarchy of the organization, and the information channels linking organization sub-systems define the functional role of the information system. In fact, the information system turns out to be a subsystem of the organization that interfaces the control subsystem with the operating subsystem. The framework aids the analyst in deriving information requirement specifications that can be validated against the organization's needs for information.