Debugging by Thinking

1

Introduction

If builders built buildings the way programmers wrote programs, the first woodpecker that came along would destroy civilization.

—Gerald Weinberg

1.1 The nature of the problem

I don’t believe that the story of a moth found in a relay of one of the first digital computers adequately explains why software defects are commonly referred to as bugs. Books on debugging often begin with a recitation of how Adm. Grace Hopper found a moth, which had shorted out an electronic relay, in the Mark II computer. While the story may be true and although there are many variations told, the aptness of the term goes far deeper than this incident.

The word “bug” is commonly used to refer both to insects and arachnids. In the natural world, bugs ...