A rational design process: How and why to fake it

Many have sought a software design process that allows a program to be derived systematically from a precise statement of requirements. This paper proposes that, although we will not succeed in designing a real product in that way, we can produce documentation that makes it appear that the software was designed by such a process. We first describe the ideal process, and the documentation that it requires. We then explain why one should attempt to design according to the ideal process and why one should produce the documentation that would have been produced by that process. We describe the contents of each of the required documents.