Lesson 167 - Architecture vs Design

Summary

In this episode of Software Architecture Monday, Mark Richards explores the nuanced differences between architecture and design in software development. He introduces a spectrum of decisions rather than a binary distinction and provides criteria to determine the nature of decisions, such as their structural impact, strategic vs. tactical nature, effort involved, and the significance of trade-offs. Using examples like choosing microservices and design patterns, Richards illustrates how these criteria can help identify who should make certain decisions and their overall system impact, offering a practical tool for developers and architects to navigate their responsibilities.

Takeaways

• 🏛 Architecture and design are not binary but a spectrum of decisions, with varying degrees of impact and responsibility.
• 🔍 The first criterion to differentiate between architecture and design is the involvement of structural aspects of the system, such as component organization and coupling.
• 📈 Strategic decisions typically involve more people, take longer to make, and have a broader impact, whereas tactical decisions are quicker and involve fewer people.
• 💪 High effort decisions are more likely to be architectural, while low effort decisions tend to be more design-oriented.
• ⚖️ Trade-offs are inherent in software architecture, with significant trade-offs usually indicating an architectural decision and less significant ones leaning towards design.
• 🤔 Determining the nature of a decision helps in identifying who should be responsible for making it, either the architect or the development team.
• 🔑 Understanding the impact of a decision is crucial; architectural decisions generally have a higher impact on the system compared to design decisions.
• 🌟 The example of choosing microservices as an architectural style demonstrates a high-impact, strategic, high-effort decision with significant trade-offs.
• 🛠 The use of a strategy design pattern is an example of a tactical, low-effort decision with less significant trade-offs, typically a design responsibility.
• 🔄 The decision to break up a payment service into separate services is a gray area, requiring analysis of structural change, strategic/tactical nature, effort, and trade-offs.
• 🛑 The criteria provided can act as a tool to determine the responsibility and impact of decisions, helping to avoid conflicts and ensure appropriate decision-making roles.

Q & A

What is the main topic of the lesson in the provided video script?

The main topic of the lesson is the difference between architecture and design in software development.

How does Mark Richards define the difference between architecture and design?

Mark Richards explains that the difference between architecture and design is not a binary decision but a spectrum of decisions that lie between architecture and design.

What is the first criterion mentioned to determine if a decision is architectural or design-related?

The first criterion is whether the decision involves some structural aspect of the system or is merely about the source code.

How can you differentiate between strategic and tactical decisions?

Strategic decisions tend to involve a lot more people and take weeks to months to make, while tactical decisions can be decided with one or two people within an hour or a day.

What does the level of effort criterion indicate about a decision?

The higher the effort required, the more architectural the decision probably is.

Why is the significance of trade-offs an important criterion in differentiating architecture from design?

Significant trade-offs usually indicate architectural decisions, while less significant trade-offs are typically associated with design decisions.

Why is it important to understand whether a decision is architectural or design-related?

Understanding this helps determine who has the responsibility for making the decision and the overall impact of the decision on the system.

What is an example of a decision that is clearly architectural?

Choosing to use microservices for a new system is an example of a decision that is clearly architectural.

Can you provide an example of a decision that is clearly design-related?

Choosing to use the strategy design pattern for a part of the code is an example of a decision that is clearly design-related.

What is an example of a decision that falls in the middle of the spectrum between architecture and design?

Choosing to break up the payment service into separate services for each payment type is an example of a decision that falls in the middle of the spectrum.

How can the criteria discussed help avoid conflicts between architects and developers?

The criteria help determine who should have the ultimate responsibility for a decision, avoiding stepping on each other's toes or making decisions that one shouldn't have the responsibility to make.

What is the overall impact of architectural decisions compared to design-related ones?

Architectural decisions tend to have a higher impact on the system compared to design-related decisions.