software architecture

When production code is important, then it is a minority: most project code is scaffolding. Tests, deployments, linting, verification, utilities for local development, handy admin interfaces–scaffolding is code that helps us safely and efficiently change production code.

• If your system requires high performance, then you need to pay attention to managing the time-based behavior of elements, their use of shared resources, and the frequency and volume of their interelement communication.


• If modifiability is important, then you need to pay attention to assigning responsibilities to elements and limiting the interaction

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The fidelity of the system increases as extensions are added, or early versions are replaced by more complete versions of these parts of the software. In some cases, the parts may be low-fidelity versions or prototypes of the final functionality; in other cases, they may be surrogates that consume and produce data at the appropriate rates but do li... See more

Software architecture is a manifestation of the earliest design decisions about a system, and these early bindings carry enormous weight with respect to the system’s remaining development, its deployment, and its maintenance life. It is also the earliest point at which these important design decisions affecting the system can be scrutinized.

Decisions at all stages of the life cycle—from architectural design to coding and implementation and testing—affect system quality. Therefore, quality is not completely a function of an architectural design. But that’s where it starts.

The benefits of incremental development include a reduction of the potential risk in the project. If the architecture is for a family of related systems, the infrastructure can be reused across the family, lowering the per-system cost of each.

This practice gained attention in the early 2000s through the ideas of Alistair Cockburn and his notion of a “walking skeleton.” More recently, it has been adopted by those employing MVP (minimum viable product) as a strategy for risk reduction.

Many systems are built as skeletal systems that can be extended using plug-ins, packages, or extensions. Examples include the R language, Visual Studio Code, and most web browsers.

A system’s ability to meet its desired (or required) quality attributes is substantially determined by its architecture. If you remember nothing else from this book, remember that.