Systems Architecture

Book Preface

We wrote this book to capture a powerful idea. The idea of the “architecture of a system” is growing in recognition. It appears in diverse fields including the architecture of a power grid or the architecture of a mobile payment system. It connotes the DNA of the system, and the basis for competitive advantage. There are over 100,000 professionals with the title system architect today, and many more practicing the role of the architect under different titles.

Powerful ideas often have nebulous boundaries. We observed that many of our co-workers, clients, students had a shared recognition of system architecture issues, but used the term in very different scopes. The term is often used to differentiate between existing systems, as in “the architecture of these two mountain bikes is different.”

What exactly constitutes the architecture of a system is often a subject of great debate. In some fields, the term is used for a singular decision that differentiates two types of systems at a high level, as in “packet-switched architecture” vs. “circuit switched architecture.” In other fields, the term is used to describe a whole implementation, save for some smaller details, as in “our software as a service architecture.”

Our goal was to capture the power of the idea of architecture, and to sharpen the boundaries. Much of the power of idea originates with the potential to trade among several architectures early, to look downstream and identify which constraints and opportunities will be central to value. It isn’t possible to trade among early ideas if the architecture encompasses all details, nor is it a meaningful exercise if important drivers of value are missing.

We wrote this book to build on the idea that the architect is a specialist, not a generalist, as proposed by Eberhardt Rechtin. Our intent is to showcase the analysis and methodologies of system architecture, and to develop the ‘science’ of system architecture. This text is less prescriptive in places than the discipline of product design, as the systems tackled are more complex. Where the product development community has a stronger focus on design, our focus centers more on emergence—the magic of functions coming together to produce a coherent whole.

We’ve imbued this book with our past experience. We’ve been fortunate to be involved in the early development of a number of complex systems in communications, transportation, mobile advertising, finance, robotics, and medical devices, ranging in complexity from farm equipment to the International Space Station.

Additionally, we have included case studies from the experience of other system architects, in disciplines ranging from hybrid cars to commercial aircraft. Our intent was that this book can only advance system architecture if it works from challenges faced by system architects today.

We wrote this book for two core audiences—professional architects and engineering students. System architecture as an idea grew out of practitioners’ wisdom and attempts to codify the challenges of developing new architecture. One core audience is senior professionals who are faced with architectural decisions. The field encompasses a variety of professionals in senior technical and managerial roles in technical industries—software, electronics, industrial goods, aerospace, automotive, and consumer goods.

This book is also focused on engineering students as a core audience. This text grew out of the graduate course we have taught at MIT for the past 15 years, where we’ve been fortunate to educate many leaders in the private sector and government. The lens of architecture helps us understand how a system operates today, but moreover, we believe that it is a necessary competency to learn in the management of technical organizations.