This talk is an essay on design. In the 16th century, Michel de Montaigne invented a new genre of writing he called an essai, which in modern French translates to attempt. Since then, the best essays have been explorations by an author of a topic or question, perhaps or probably without a definitive conclusion. Certainly there can be no theme or conclusion stated at the outset, repeated several times, and supported throughout, because a true essay takes the reader on the journey of discovery that the author has or is experiencing.

This essay -- on design -- is based on my reflections on work I’ve done over the past 3 years. Some of that work has been on looking at what constitutes an “ultra large scale software system” and on researching how to keep a software system operating in the face of internal and external errors and unexpected conditions.

In this presentation I’ll look at the nature of design through the lenses these two inquiries provide. Namely, what can we learn of design when we look at an extreme design situation, and when we look at how to give a system the characteristic of homeostasis: the ability of a system to regulate its internal environment to maintain a stable, constant condition. The exploration is what we can learn about design when we examine design situations that are beyond (current) human abilities.