Chapter 1 - What is Design and Architecture?

• No difference between design and architecture

  • Often split to mean that architecure is high level and design is low level
  • Distinction is nonsensical
  • Architecture of a house includes every light, switch, outlet
  • Little detalis support high level decisions
  • Continuous fabric which defines the shape of the system

• Measure of design quality is the effort required to meet the needs of the customer

• Case study

  • Exponential growth of engineering staff
  • Growth of the code reached an asymptote
  • Cost per line of code exponential
  • No thought given to cleanliness or structure
  • productivity declines with every release

• Tortoise and the hare

  • "We can clean it up later"
  • But no time for that, have the next feature to develop
  • Overconfident in ability to remain productive
  • Making messes is always slower, even on short time scales

• Jason Gorman's experiment

  • Every day he wrote a program to convert decimals to roman numerals
  • Used TDD every odd number day
  • Got faster over time
  • But all the TDD days were significantly faster ~ 10%
  • The slowest TDD day was faster than the fastest non TDD day

• The only way to go fast is to go well

• The only way to address the decline in productivity is to take responsibility for the mess

  • Not to restart from scratch and make another mess