In their seminal work “Documenting Software Architectures: Views and Beyond” Paul Clements and the rest of the authors chose a bird’s wing picture for their book cover, and they beautifully describe how they use the bird’s wing physiological system as a new and rich metaphor for software and system architectures.
The authors in an introduction brief meant to convey the purpose and attract readers, draw a comparison between a Holism and a Reductionism approaches to describing complex systems such as systems that intensively rely on software components.
I chose to quote rather long passages from this book’s introduction here, I hope authors won’t mind.
They start asking “How would you “document” a bird’s wing for someone who did not know what it was?”
And then continue answering “A bird’s wing, like a software system, can be shown by emphasizing any of a number of structures—feathers, skeleton, circulatory system, musculature”
Here they decide that software system can be looked at from different viewpoints, which is a standard reductionist approach to comprehend any complex system.
Bird’s Wing for Renaissance artist Albrecht Durer (1471-1528)
In Paul’s and his colleagues opinion the dynamic attributes of the Wing system is what makes it unique, I would even go and say that they think that dynamic quality attributes are superior and more architecture critical than static quality attributes.
They say “The wing exhibits strong quality attributes: lightness in weight, aerodynamic sophistication, outstanding thermal protection. The wing’s reliability, cycling through millions of beats, is unparalleled. Unlike a house, which mostly just sits there, the essence of a wing is in its dynamic behavior. In coarse terms, the wing extends, flaps, and retracts; in finer terms, the bird commands movements almost too subtle to see, controlling pitch, roll, and yaw with exquisite finesse.”
At the end of this amazing piece they chose to introduce their book, they turn into admiring the whole system, where the total of the system is actually more than mechanical sum of the parts.
They say” For millennia, humans have tried to comprehend the wing by examining its parts and from different points of view. But the whole wing is much more than the sum of its elements and structures: It is in the whole that beauty and grace emerge. Mankind’s technology still cannot replicate the wing’s exquisite abilities. The common starling, a merely average flier, can slip through the air at 21 body lengths per second. That’s about what the world’s fastest aircraft—at 2,000 miles per hour—is able to manage.
Structure, substructure, replication with variation, behavior, quality attributes, and emergent properties of the entire system: All these aspects are important to capture when documenting a software architecture.”
Finally they pose a question, it is true that we have our humble trials to capture and understand a complex and beautiful creation of Allah but our tools are far limited from being able to describe its beauty and grace!
They say” We haven’t learned how to document beauty and grace yet, but for that we substitute the documentation of rationale, or what the designer had in mind. For software, we can do this. For the wing of a bird, we can only admire the result.”
Always moved by these last lines, the best book introduction I have read ever!
Salam
program completely online, the program which costs a fraction of the on-campus counterpart is a leap step toward democratizing fine education and make it available to the masses.
