> Good architecture is almost timeless.

As long as nothing changes, I can agree with you. But that's the point of architecture in the first place, to be there for you when things change. The focus of architects should be to ensure that changes are as easy as possible and not to have an elegant design. I've seen some of the most elegant designs that are easy to maintain trashed due to changes in user requirements or changes to the market place.

For this reason I advocate, and have advocated since I started developing in the early 90s, micro service/modular architectures. Java OSGi is currently my favorite environment (though I'm also investigating similar approaches in Clojure), but I've done this with C/C++ in the past as well using shared objects/dlls as the modularity mechanism.

Good architectures adapt to change, they doesn't stay the same with time.

Elegance doesn't matter; simplicity does in the face of changing requirements. Or rather, elegance falls out of this simplicity. It's an emergent property, rather than an explicit aim. Thus, my favorite designs have traditionally resembled a microkernel in approach, where the kernel of the app exists only to facilitate disparate services to find and use one another. Interfaces are kept to an absolute minimum, and concerns like UIs or persistence are pushed to the edge of the system, where they should be. This design facilitates division of labor well; more novice developers can make a mess within their subsystem, yet have the damage contained. I usually bolt a pub/sub mechanism on relatively quickly, as this requirement is almost a given with a UI.

Dynamic loading is indeed the ultimate modularity. Combined with this microkernel approach, extensions are just as powerful as built-in services. The only problem is you enter a new hell: managing dependencies/versions of the core vs the extensions. If you can control the release of the extensions as well as the core, you're set.

> Good architecture is almost timeless.

Never dismiss the dangers of over-engineering. While not as terrifying as under-engineering, how useful is a feature that exists only for the purity of design?

Over-engineering is a problem because it usually results in a much more complicated design than you really need and wastes a lot of time.

However, over-engineering and spending quality time thinking about the design and domain are two separate things and typically the more you think about the design and domain the less likely you are to over-engineer.

And Over-Engineering is something people only learn to spot once they've designed and built a few systems and had to maintain them for a few years. Its fairly easy to teach design-principle-du-jour but quite hard to teach about over engineering, KISS and YAGNI.

Developers tend to want to generalise everything because it makes it more interesting and has the appearance of good design. But generalising in one direction reduces flexibility in other directions. Better to copy and paste a bit at first and wait a bit before adding that extra extraction layer that generalises Foo.

I think a lot of it comes down to developers focusing on their own personal learning and development and not what is best for the current project.

Very few workplaces will let you work hard for 5 hours solving problems in the most time effective way and then spend the next 3 hours on your personal development.

On the other hand you can always spread the work over 8 hours and "experiment" with "on the job learning" leaving all sorts of sub-optimal solutions in the project. Then the next guy goes "Why on earth did Jim use X here?" and the truthful answer is because Jim wanted to learn more about X.

Yeah, I've heard several devs say something like 'Why did Jim do this...oh, crap, he was geeking out on this new thing.'

What we're looking for in design is simpler. Simpler becomes conceptually harder very quickly, because it means challenging a lot of assumptions and opening up some unknowns.

The tried-and-true implementation has a known initial cost and cost scaling factor as it's repeated throughout an application, while an experimental (and overdesigned) one is extremely sensitive to context and could become a net negative if it fails.

When we talk about "technical debt," I think we're describing something that isn't an experimental design, it's just "below" the known standard - it's faster to implement, but it cannot scale, and we already know that. Conversely, a standard practice is one that works and doesn't usually get pushed to its tolerance limits.

The corollary of this is that for any engineering project taking on a big enough problem, you have to assume some technical debt to ground the system in a place where each module can be tested as part of a whole: otherwise your work will go too deep into the experimental/overdesigned zone before it ever completely functions.

I see lots of worry about over-engineering on the Internet, and little in practice. I'm sure it happens, but under-engineering is way more common.

Yeah, in my experience, "no engineering" is the most abundant; everything is thrown together willy-nilly to code as fast as possible. I have come across very few real cases of over engineering.

Part of my point is that you don't feel over-engineering nearly as much. If it is under-engineered, it probably doesn't work, and at least has a list of pain points that are fairly obvious.

Over-engineered components will work (sometimes flawlessly), so you don't realize you've spent too much time and money on something until long after you built it.

Over-engineering ISN'T good architecture. It's just as much bad architecture as under engineering.

;)

Yes, never dismiss it. In fact a lot of the time over-engineering is just another form of technical debt, but it also has an upfront cost as well. At least the under engineered solution is cheap up front.

I would much rather come across something under engineered than over engineered.

So, at one time, relational databases were considered 'new'. Entire programs and the data they used were stored in a single file by most development teams.

It was considered good architecture to keep everything together. Many established and well-respected developers argued against relational data, because they said 'it splinters all of the data' and modular programming 'splits up the application logic all over God-knows-where'.

Some people still argue if Linux and it's monolithic kernel is better or worse than Windows modular design. These are two completely different architectural schools, and yet both have people who consider one good design, and the other flawed beyond repair. It doesn't matter which, take your pick, they both have zealots and detractors.

So, saying 'good architecture is timeless' is kind of general for me.

Things you consider to be absolute today will change and be defunct in five years.

I think consistency plays a big role here.

If you're into small modules, stay consistent and separate things. If you're into OO-design, try to encapsulate and make your objects re-usable.

When you start losing this consistency and drift away from the architectural vision in order to make quick-wins ("lets just tuck this feature to this module even though it might not really belong there..."), that's when things turn into mud.

Understanding the architecture and its philosophy gives you a big insight into the code, the way its structured, where things fit together. It saves you time.

With solid architecture you know where to change things and where to add them. I think it's timeless in this sense. Its consistency applies everywhere. Once you 'get it', and stick to it, things make sense.