Mary discusses how changes in complex systems can be successfully made only through small probes; but how these probes are introduced depends on the amount of abstraction and federation in the architecture. Approaching systems design and implementation from a perspective of proper abstraction, proper federation, and honesty when dealing with failure can yield resilient, flexible, and productive systems.

Big Design Upfront was considered so evil in the early days of Agile that it acquired its own four-letter abbreviation. All you had to do was accuse someone of doing BDUF, and they were ostracized from agile discussions. When the Build-Measure-Learn model became popular and Continuous Delivery became practical, design became further marginalized. Enter Big Data, and well – who needs design?

We do. When it comes to design, we’ve thrown the baby out with the bathwater – a common practice when new processes are reactions to the excesses of old practices. But absent the careful thinking of good designers, our systems turn out to be mediocre collections of stuff that customers asked for or the data showed was desirable. It’s time we relearned that great products start with asking the right questions.