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The line between software development and software architecture is a tricky one. Some people will tell you that it doesn't exist and that architecture is simply an extension of the design process undertaken by developers. Others will make out it's a massive gaping chasm that can only be crossed by lofty developers who believe you must always abstract your abstractions and not get bogged down by those pesky implementation details. As always, there's a pragmatic balance somewhere in the middle, but it does raise the interesting question of how you move from one to the other.

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Some of the key factors that are often used to differentiate software architecture from software design and development include an increase in scale, an increase in the level of abstraction and an increase in the significance of making the right design decisions. Software architecture is all about having a holistic view and seeing the bigger picture to understand how the software system works as a whole. While this may help to differentiate software development and software architecture, it doesn't necessarily help to understand how somebody moves from development into architecture. Furthermore, it also doesn't help in identifying who will make a good software architect, how you go about finding them if you're hiring and whether you are a software architect.

Experience is a good gauge but you need to look deeper

Becoming a software architect isn't something that simply happens overnight or with a promotion. It's a role, not a rank. It's an evolutionary process where you'll gradually gain the experience and confidence that you need to undertake the role.

There are a number of different qualities that you can look for in a software architect and their past experience is often a good gauge of their ability to undertake the role. Since the role of a software architect is varied though, you need to look deeper to understand the level of involvement, influence, leadership and responsibility that has been demonstrated across a number of different areas. Broadly speaking, the software architecture on most projects can be broken down into two phases; the architecture is defined and then it's delivered.

Definition of the software architecture

The architecture definition process seems fairly straightforward. All you have to do is figure out what the requirements are and design a system that satisfies them. But in reality it's not that simple and the software architecture role can vary wildly depending on how engaged you are and how seriously you view your role. As the following diagram shows, the architecture definition part of the role can be broken down further into a number of different elements.

Management of non-functional requirements: Software projects often get caught up on asking users what features they want, but rarely ask them what non-functional requirements (or system qualities) they need. Sometimes the stakeholders will tell us that "the system must be fast", but that's far too subjective. Non-functional requirements need to be specific, measurable, achievable and testable if we are going to satisfy them. Most of the non-functional requirements are technical in nature and often have a huge influence on the software architecture. Understanding the non-functional requirements is a crucial part of the role, but there's a difference between assuming what those requirements are and challenging them. After all, how many systems have you seen that genuinely need to be operational 24x7?

Architecture definition: With the non-functional requirements captured, the next step is to start thinking about how you're going to solve the problems set out by the stakeholders and define the architecture. It's fair to say that every software system has an architecture, but not every software system has a defined architecture. And that's really the point here. The architecture definition process lets you think about how you're going to take the requirements along with any imposed constraints and solve the problem. Architecture definition is about introducing structure, guidelines, principles and leadership to the technical aspects of a software project. Defining architecture is your job as a software architect but there's a big difference between designing a software system from scratch and extending an existing one.

Technology selection: Technology selection is typically a fun exercise but it does have its fair set of challenges when you look at cost, licensing, vendor relationships, technology strategy, compatibility, interoperability, support, deployment, upgrade policies, end-user environments and so on. The sum of these factors can often make a simple task of choosing something like a rich client technology into a complete nightmare. And then there's the question of whether the technologies actually work. Technology selection is all about managing risk; reducing risk where there is high complexity or uncertainty and introducing risk where there are benefits to be had. Technology decisions need to be made by taking all factors into account, and all technology decisions need to be reviewed and evaluated. This includes the major building blocks for a software project right down to the libraries and frameworks being introduced during the development. If you're defining an architecture, you also need to be confident that the technology choices being made are the right choices. Again there's a big difference between evaluating technology for a new system versus adding technology into an existing system.

Architecture evaluation: If you're designing software, you need to ask yourself whether your architecture will work. For me, an architecture works if it satisfies the non-functional requirements, provides the necessary foundation for the rest of the code and provides a sufficient platform for solving the underlying business problem. One of the biggest problems with software is that it's complex and abstract, which makes it hard to visualise the runtime characteristics from UML diagrams or the code itself. We undertake a number of different types of testing throughout the software development lifecycle to give us confidence that the system we are delivering will work when rolled out. So why don't we do the same for our architectures? If you can test your architecture, then you can prove that it works. And if you can do this as early as possible, you can reduce the overall risk of project failure rather than simply hoping for the best.

Architecture collaboration: It's unusual for any software system to live in isolation and there are a number of people that need to understand it. This ranges from the immediate development team who need to understand and buy in to the architecture, right through to other stakeholders who have an interest from a security, database, operations, maintenance, support, etc point of view. For a software project to be successful, you need to collaborate closely with all of the system stakeholders to ensure that the architecture will successfully integrate with its environment. Unfortunately, architecture collaboration within the development team seldom happens, let alone the external stakeholders.



Delivery of the software architecture

It's the same story with architecture delivery too, where the software architecture role can vary depending on the level of engagement across the elements that contribute to a successful software project.

Ownership of the bigger picture: In order to carry the architecture through to a successful conclusion, it's important that somebody owns the big picture and sells the vision throughout the entirety of the software development lifecycle, evolving it throughout the project if necessary and taking responsibility for ensuring that it's delivered successfully. If you've defined an architecture, it makes sense to remain continually engaged and evolve your architecture rather than choosing to hand it off to an "implementation team".

Leadership: Owning the bigger picture is one aspect of technical leadership, but there are other things that need to be done during the delivery phase of a software project. These include taking responsibility, providing technical guidance, making technical decisions and having the authority to make those decisions. As the architect, you need to undertake the technical leadership to ensure everything is taken care of and that the team is being steered in the right direction on a continuous basis. The software architect position is inherently about leadership and while this sounds obvious, many project teams don't get the technical leadership that they need, with architects assuming that a successful delivery isn't necessarily their problem.

Coaching and mentoring: Coaching and mentoring is an overlooked activity on most software development projects, with many team members not getting the support that they need. While technical leadership is about steering the project as a whole, there are times when individuals need assistance. In addition to this, coaching and mentoring provides a way to enhance people's skills and to help them improve their own careers. This is something that should fall squarely within the remit of the software architect, and clearly there's a big difference between coaching your team in architecture and design versus helping them with their coding problems.

Quality assurance: Even with the best architecture and leadership in the world, poor delivery can cause an otherwise successful project to fail. Quality assurance is a large part of an architect's role, but it's more than just doing code reviews. For example, you need a baseline to assure against, and this means the introduction of standards and working practices. From a software development perspective, these could include coding standards, design principles and source code analysis tools through to the use of continuous integration, automated unit testing and code coverage tools. It's safe to say that most projects don't do enough quality assurance, and therefore you need to figure out what's important and make sure that it's sufficiently assured. For me, the important parts of a project are anything that is architecturally significant, business critical, complex or highly visible. You just need to be pragmatic and realise that you can't necessarily assure everything, doing something rather than doing nothing.

Design, development and testing: The last thing that falls squarely within the role of a software architect is design, development and testing. Being a hands-on architect doesn't necessarily mean that you have to get involved in the day-to-day coding tasks, but it does mean that you're continuously engaged in the project, actively helping to shape and deliver it. Having said that, why shouldn't the day-to-day coding activities be a part of an architect's role? Most architects are experienced coders, so it makes sense to keep those skills up-to-date. In addition, the architect can experience the same pain as everybody else on the team, which in turn helps them better understand how their architecture is viewed from a development perspective. Many companies have policies that prevent software architects from engaging in coding activities because their architects are "too valuable to undertake that commodity work". Clearly this is the wrong attitude ... why let your architects put all that effort into defining the architecture if you're not going to let them contribute to its successful delivery? Of course, there are situations where it's not practical to get involved at the code level. For example, a large project generally means a bigger "big picture" to take care of and there may be times when you just don't have the time. But generally speaking, an architect that codes is more effective and happier than an architect that watches from the sidelines.



Are you a software architect?

Regardless of whether you view the line between software development and architecture as mythical or a gaping chasm, the elements above highlight that people's level of experience across the software architecture role varies considerably depending on how engaged they are and how seriously they view their role. Most developers don't wake up on a Monday morning and declare themselves to be a software architect. I certainly didn't and my route into software architecture was very much an evolutionary process. Having said that though, there's a high probability that those same developers are already undertaking parts of the software architecture role, irrespective of their job title.

There's a big difference between contributing to the architecture of a software system and being responsible for defining it yourself; with a continuum of skills, knowledge and experience needed across the different areas that make up the software architecture role. Crossing the line between software developer and software architect is up to you, but understanding your own level of experience is the first part of the journey.

About the Author

Depending on your viewpoint, Simon Brown is either a software architect who codes or a software developer who understands architecture. When he's not developing software with .NET or Java, Simon can usually be found consulting, coaching or training. Simon has also written books about Java, presented at industry events and has put together a training course called Software Architecture for Developers, which is based upon his software architecture writing at Coding the Architecture. You can catch up with Simon by e-mail or Twitter.