Partial comprehension of complex programs (enough to perform maintenance)

Many legacy programs are so large and so complex that they cannot be comprehended in their entirety no matter what forms of representation are used. Yet these programs must be maintained. The contention of this paper is that it is not necessary to comprehend a program in order to maintain it. It is only necessary to comprehend those sectors affected by the maintenance request. Only seven questions are required to pinpoint and comprehend program sectors well enough to be able to alter them without undesired side effects. These questions and their answers are proposed in the following paper