The document discusses lessons learned from architectural thinking. It warns against allowing prior knowledge, abstractions, specific goals, laziness, or lack of time to stop rigorous architectural thinking. It acknowledges thinking must stop at some point for proven patterns, during implementation, or with limited resources. Supporting thinking requires self-awareness, embracing discomfort, and using practices/processes. Architectural thinking is about critically analyzing system structures for qualities, not convenience or familiar approaches. Common traps include relying only on experience, abstracting away design problems, prioritizing coding over other phases, or being vague in thinking.

1. What have you learned?
• Ruby & Ruby on Rails: 182 hours
• Yoga teacher: 200 hours
• Architectures course: 196 hours
= $1421 in a minimum wage position

2. Architectural Thinking
• Thinking about system structures
critically important for system qualities
• NOT about conventional
• NOT about convenient
• NOT about known
• NOT speaking
• NOT writing or diagramming

3. Jackson’s Denials
• Prior experience
• Hacking
• Abstraction
• Vagueness
... applicable as common traps of
architectural thinking?

4. Denial of Thinking by Prior Knowledge
● “I have used this system before, so I
know what it should be like”
● “The only problem we have is
performance. We just don't know how to
make the system faster”
• Failure to think beyond one's current
frame of experience
• Does NOT mean prior experience is bad

5. Denial of Thinking by Abstraction
• “I have an architectural diagram, therefore
I can start implementation”
• An abstraction helps avoid hard design
problems
– Never thinking or forgetting what
symbols mean
• Failure to come up with an abstraction that
supports thinking, not shuts it down
• Does NOT mean abstraction is bad

6. Denial of Thinking by Hacking
• “Drivers, requirements, and diagrams are
worthless – code is what matters”
• “I am a software engineer and care about
software, not about museums”
• Skipping hard parts of thinking
– Jumping to the solution instead of
considering the problem
– A popular combination of denials by prior
knowledge and abstraction
● Does NOT mean experimenting is bad

7. Denial of Thinking by Vagueness
• “Customers make an order, which is processed
by middleware and executed by the shipping
department.”
• “This component satisfies the security quality
attribute”
• Being not explicit about the subject of your
thinking:
– World vs. system
– Problem vs. solution
– As is vs. as to be

8. Lesson
• Don’t let
– Your knowledge and experience
– Abstractions (conventional and your own)
– Specific goals
– Laziness
– Lack of time
stop you from architectural thinking

9. Caution
• Know when to stop thinking:
– Proven patterns and methods
– Design phase
● Acceptable to start with vague
– Limited resources

10. Support your thinking
• Self-awareness, reflection
• Chase intellectual discomfort
– Confusion, mistakes
• Practices & processes

11. References
• Michael Jackson, The World and The
Machine in Proceedings of the 17th
International Conference on Software
Engineering, 1995.