Seth Godin whose blog can be found here, posted a wonderful entry called The extraordinary software development manager yesterday which contains some great axioms for managing complex software projects, the last of which is something I wish I’d written! Here is what it says:
Programming at scale is more like building a skyscraper than putting together a dinner party. Architecture in the acquisition of infrastructure and tools is one of the highest leverage pieces of work a tech company can do. Smart architecture decisions will save hundreds of thousands of dollars and earn millions. We’ll only make those decisions if we can clearly understand our options.
As I’ve said elsewhere architecture decisions are one of the most crucial social objects to be exchanged between stakeholders on a software development project. For a very thorough description of what architecture decisions are and how they can be captured see the article Architecture Decisions: Demystifying Architecture by Jeff Tyree and Art Akerman. However you don’t need to make every decision to such a precise level of detail. At a minimum you just need to make sure you have looked at all options and assumptions and have captured the rationale as to why the decision was made. Only then can you move forward reasonably safe in the knowledge that your decisions will stand the test of time and, as a bonus, will be transparent for all to see and to understand the rationale behind them.
Good architecture decisions will form part of the system of record for the project and the system itself, once it is built. They will allow future software archeologists to delve deeply into the system and understand why it is the way it is (and maybe even help fix it). They also help newcomers to the project understand why things are the way they are and help bring them up to speed more quickly on the project. Finally, and possibly most importantly of all, they stop others making different decisions later on with possibly great financial implications to the project. If you can read and understand the rationale behind why a decision was made you are less likely to overturn the decision or ignore it all together.