Great Systems Engineering Definitions Hiding in a Business Book

I’ve been reading Stratechery since it was founded, so it was inevitable that at some point I’d get around to reading The Innovator’s Dilemma and The Innovator’s Solution. Both were great, as I expected. I did not expect a business book to have such great, concise definition for terms I use all the time as a systems engineer.

From The Innovator’s Solution:

• “A product’s architecture determines its constituent components and subsystems and defines how they must interact—fit and work together—in order to achieve the targeted functionality.”
• “The place where any two components fit together is called an interface. Interfaces exist within a product, as well as between stages in the value-added chain.”
• “[In an interdependent] architecture…the way one [part] is designed and made depends on the way the other is being designed and made. … Interdependent architectures optimize performance, in terms of functionality and reliability.”¹
• A modular architecture integrates components and subsystems with modular interfaces.
• An effective modular interface enables a “firm to procure something from a supplier or partner, or sell it to a customer”, and satisfies “three conditions — specifiability, verifiability, and predictability”. “First, both suppliers and customers need to know what to specify — which attributes of the component are crucial to the operation of the product system, and which are not. Second, they must be able to measure those attributes so that they can verify that the specifications have been met. Third, there cannot be any poorly understood or unpredictable interdependencies across the customer-supplier interface. The customer needs to understand how the subsystem will interact with the performance of other pieces of the system so that it can be used with predictable effect.”
• “…we will use the term subsystem to mean, generally, an assembly of components and materials that provides a piece of the functionality required for an end-use system to be operational.”