Defining Software Architecture

The role of software architecture can sometimes be difficult to define, it can be easy to demonstrate its absence when a project or a system is saddled with technical debt but the impact when its being done well can sometimes be missed because the apparent simplicity it fosters.

However software architecture should not be an isolated pursuit, it should be a tool to achieve the aims of an organisation, when this is applied well the goals of the architect and the goals of the organisation are symbiotic.

It can sometimes be trite to attempt to simplify complex subjects into bullet points or pearls of wisdom, the points made here are not an attempt to do this, they are simply trying to help in providing an explanation for the role of software architecture.

Modularity and Patterns

The creating of software is an expensive pursuit, individuals skilled in its production are an expensive resource. This means that every last drop of value needs to be squeezed from their efforts, in short there is an economic benefit to code re-use. 

Every time a piece of code is re-used the value returned on the original effort to produce it is increased.

Code re-use is only viable when the opportunity for re-use can be seen and the code itself can be cleanly extracted. Good architecture provides structure and patterns for implementation that promote both of these aspects and make it more likely that code, and the value it provides, can be re-used.

Good architecture also provides a framework for code, both old and new, to be stitched together to form a coherent system that can meet objectives. Bad architecture breeds re-writes and duplication where the achievement of value always comes at an expensive cost.

Flexibility

The priorities of a business are subject to change, the predictability of the frequency and direction of that change can vary.

Good architecture can adapt to these shifting sands and demonstrate a flexibility in the things it can achieve.

In part this is accomplished by the same modularity we've previously talked about, when a system is the sum of its parts then these parts can be re-worked and replaced without having to contemplate starting from scratch or undertake major surgery on a code base.

The second, equally important, aspect to flexibility is that this change can be quickly deployed.

It is fast becoming a fact that the effectiveness of a software engineering function can be measured by the frequency in which it deploys code. Against this backdrop an architecture that can't deliver a fast pace and unrestricted frequency of deployments will be deemed ineffective and lacking.

Good architecture wouldn't be overly simplified by being categorised as the smooth implementation of business change. 

Containing Complexity

Writing software is a complicated business, it is so incredibly easy to do it wrong. Coupled with this the businesses and domains that it is attempting to model and facilitate are often equally complex.

Without a good architecture to provide a path through this complexity software can become fragile, ineffective and ultimately a burden on the organisation it is designed to serve.

A good architecture recognises this tendency towards complexity and the problems that can bring. To counteract this it tries to simplify where possible and contain complexity where this isn't possible.

Understanding where complexity lies in a system allows care to be taken when modifying these areas while allowing the speed of development in areas freed from complexity to be increased.

A bad architecture breeds complexity and allows it to put the brakes onto development activity, it makes it more likely that change will bring unintended consequences and acts as a multiplier for these effects having an even bigger impact in the future.

As mentioned at the start of this post software architecture can't be summed up in so few words as we have here, it is an activity that is very difficult to become proficient at and potentially cannot be mastered.

However, having certain goals in mind and being able to explain its benefits can help to garner an appreciation for the discipline and an understanding for the pitfalls of not giving it proper consideration.

Good architecture can be undermined when it takes a complex situation and makes it appear straight forward, sometimes its presence is only felt when bad architecture lays out this complexity for all to see.