Simon Brown’s 4C model - Intro

This learning hour introduces the basic ideas in The C4 model for visualising software architecture

Learning Goals

• list the names of the four models in the 4C model
• describe the problem which the 4C model solves
• sketch a Context diagram
• distinguish between important elements to show in a Context diagram and details to exclude

Session Outline

• 5 min connect: What are diagrams for?
• 20 min concrete: analyse and draw diagrams for Instavoiced
• 10 min concept: 4C model
• 10 min concrete: draw Context diagram
• 10 min conclusions: compare original diagrams with Context diagram

Connect: What are software architecture diagrams for?

Think about what you already know about software architecture diagrams. Write three facts on postits. Be ready to state them when asked. (Think it then ink it)

When everyone has written something, pair them up and have them share their facts to one another. You can continue working in the same pairs in the rest of the session.

Concrete: analyze Instavoiced

Working in pairs, read the description of the Instavoiced system.

• Sketch a high-level architecture for this system
• Document your architectural decisions in one or more diagrams

Use paper or a whiteboard.

Concept: 4C model

The front page of the The C4 model for visualising software architecture website explains these concepts. Present them in your own way.

• why we need architectural diagrams
• the analogy with zooming in on a map
• the four core diagrams
• the main abstractions used on the diagrams

Concrete

Continuing with the same Instavoiced system, start over on your diagrams. Draw a Context diagram. Use paper or a whiteboard.

Conclusions

Each pair posts their original and new diagrams in a place where everyone can see them. Walk around and look at everyone’s diagrams. Each person should note for themselves what is important to include or not include in a Context diagram.