Sunday, April 19, 2009

Historical Footnote on Design Patterns

When it rains, it pours. I recently attended an excellent talk on "Design Patterns Reconsidered" by Alex Miller. Around the same time, I was listening to a Software Engineering radio podcast (on Adrenalin Junkies) and heard a comment that merits amplification.

Many people know (or would know, if they attended Alex's talk) that the seminal book, Design Patterns, was heavily influenced by books on architecture by Christopher Alexander. In Design Patterns, the now-famous Gang of Four certainly discuss Alexander, and list patterns-based literature of the era, vis-a-vis software architecture -- but there isn't much on the semantic gap between architecture and computer science. How did we discover Alexander in the first place?

On the podcast, a woman points out that Peopleware is one of the first known books on software to reference Alexander's works (though note that the context is organizing office space).

Tom deMarco acknowledges the comment, but states that Edward Yourdon was a major factor in bringing the book into consciousness of IT (in the early 1970s). Though he can only comment for himself (and not the Gang of Four), deMarco goes on to say that he owes "a personal debt" to Yourdon.

Perhaps, we all owe thanks?


Ed Yourdon said...

I found out about Christopher Alexander from my friend and coauthor (of "Structured Design"), Larry Constantine, who introduced me to Alexander's 1964 book, "Notes on the Synthesis of Form".

I think most of Alexander's popularity amongst computer professionals came later, after "A Pattern Language" and "The Timeless Way of Building".

Anyway, you'll have to ask Larry Constantine who told him about Christopher Alexander...

Ed Yourdon

Michael Easter said...


Thanks for dropping by and contributing to the history of the tale.

Readers, take note, we owe a debt to Larry Constantine as well.

re: ask Larry. My hope is that it was a classic late-night discussion at a university student center that gave us the connection.

How much does humanity owe to the statement "By the way, you might be interested in this book...." ?