Constraint driven software design: an escape from the waterfall model

This paper presents the principles of a development methodology for software design. The methodology is based on a nonlinear, product-driven approach that integrates quality aspects. The principles are made more concrete in two examples: one for developing educational simulations and one for developing expert systems. It is shown that the flexibility needed for building high quality systems leads to integrated development environments in which methodology, product and tools are closely attuned to each other. This "development process reengineering" can lead to significant improvements in the quality of the product in terms of both maintainability and performance enhancement of the people involved in the development process.