Kimsia

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.

If you want your implementation to conform to an architecture, then it must conform to the design decisions prescribed by the architecture. It must have the set of elements prescribed by the architecture, these elements must interact with each other in the fashion prescribed by the architecture, and each element must fulfill its responsibility to t... See more

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

once the architecture has been agreed upon, it becomes very costly—for managerial and business reasons—to significantly modify it. This is one argument (among many) for analyzing the software architecture for a large system before settling on a specific choice.

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.

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.

Every architecture, no matter what it is, partitions possible changes into three categories: local, nonlocal, and architectural.

• A local change can be accomplished by modifying a single element—for example, adding a new business rule to a pricing logic module.


• A nonlocal change requires multiple element modifications but leaves the underlying archite

... See more

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.

• 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

... See more