The Mythical Man-Month: Essays on Software Engineering

by Frederick P. Brooks Jr.

Cosgrove advocates treating all plans, milestones, and schedules as tentative, so as to facilitate change. This goes much too far—the common failing of programming groups today is too little management control, not too much. Nevertheless, he offers a great insight. He observes that the reluctance to document designs is not due merely to laziness or time pressure. Instead it comes from the designer's reluctance to commit himself to the defense of decisions which he knows to be tentative. "By documenting a design, the designer exposes himself to the criticisms of everyone, and he must be able to defend everything he writes. If the organizational structure is threatening in any way, nothing is going to be documented until it is completely defensible." Structuring an organization for change is much harder than designing a system for change. Each man must be assigned to jobs that broaden him, so that the whole force is technically flexible. On a large project the manager needs to keep two or three top programmers as a technical cavalry that can gallop to the rescue wherever the battle is thickest. Management structures also need to be changed as the system changes. This means that the boss must give a great deal of attention to keeping his managers and his technical people as interchangeable as their talents allow.

A computer program is a message from a man to a machine. The rigidly marshaled syntax and the scrupulous definitions all exist to make intention clear to the dumb engine. But a written program has another face, that which tells its story to the human user. For even the most private of programs, some such communication is necessary; memory will fail the author-user, and he will require refreshing on the details of his handiwork. How much more vital is the documentation for a public program, whose user is remote from the author in both time and space! For the program product, the other face to the user is fully as important as the face to the machine.