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What we talk about when we talk about software

Nat Pryce
October 05, 2017

What we talk about when we talk about software

Half-formed thoughts about metaphor, technical debt & Conway's law.

Presented at Software Craftsmanship London 2017

Video of the presentation: https://youtu.be/syLjjmRgTsE

Nat Pryce

October 05, 2017
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  1. What we talk about when we talk about software Half-formed

    thoughts about metaphor, technical debt & Conway's law Nat Pryce [email protected] @natpryce github.com/npryce speakerdeck.com/npryce
  2. A Layered Architecture Diagram Hardware Device Drivers Operating System Application

    Hardware Device Drivers Operating System Application Or? Which feels right?
  3. Unix Pipes tr -cs A-Za-z '\n' | tr A-Z a-z

    | sort | uniq -c | sort -rn | sed ${1}q
  4. “Each XP software project is guided by a single overarching

    metaphor. Sometimes the metaphor is "naive". ... Sometimes the metaphor needs a little explanation. The words used to identify technical entities should be consistently taken from the chosen metaphor.” eXtreme Programming Explained, Kent Beck, 1999 XP's System Metaphor
  5. Figurative Metaphor Metaphors We Live By, Lakoff and Johnson, 1980.

    “...in getting us to try to understand how it could be true, it makes possible a new understanding…”
  6. Idioms: Metaphors that have Kicked the Bucket Figurative metaphors can

    become common phrases in language When we forget the original meaning of the phrase, it loses its explanatory power. The phrase fossilises as an idiom
  7. Cognitive Metaphor We live ➢ in the physical world ➢

    in social groups We conceptualise anything more abstract as metaphor
  8. Example: MORE IS UP From The Guardian website, 15/05/2014: “OVO

    Energy raises prices 3%” “...soaring values have revived idea of selling part of property portfolio...” “...nation's top 10% owning 44% of household wealth...” “Ministry of justice figures show number of convictions fell by only 69...” “Labour's nosedive in the opinion polls…”
  9. Cognitive Metaphor Domains Up/Down, Close/Far, Facing towards/away Large/Small Inside/Outside, Boundary,

    Surface Extent, Covering, … Light/Heavy Bright/Dark Parent/Child, Siblings, ... ... Orientation Size Containment Surface Weight Shade Family ...
  10. A Layered Architecture Diagram Hardware Device Drivers Operating System Application

    Hardware Device Drivers Operating System Application Or? Which feels right?
  11. Mapping onto Different Target Domains Up Down etc. More Less

    Happy Sad Pure Corrupt Abstract Concrete People Animals Controlling Controlled
  12. Vertical Orientation ABSTRACT IS UP CONTROL IS UP PEOPLE IS

    UP HARDWARE IS DOWN (STATIC) DEPENDENCIES POINT DOWNWARDS ...
  13. Containment PROGRAMMING LANGUAGES ARE CONTAINERS CONTROL AT THE CENTER VULNERABLE

    IN THE CENTER “The system is in Java” Encapsulation Leaky abstractions Privilege ring levels ...
  14. User-facing features Front-end developer Database back-end Externally facing services ...

    Orientation: Facing Towards Something THE SYSTEM FACES THE USER THE SYSTEM FACES OTHER SYSTEMS
  15. Size Big Data “Big Iron” (mainframes) Software design diagrams could

    make better use of BIG IS IMPORTANT BIG IS IMPORTANT BIG IS POWERFUL
  16. Entailment and Coherence Read: “Following the report, shares in XYZ

    Plc took a nosedive and were in freefall by close of trading.” Think: “I should bail out of my investment in XYZ Plc. before the stock hits rock bottom.”
  17. Database ORM Domain Model UI Or? Database ORM Domain Model

    UI Which feels right? Inadvertent Entailment: Layers, Balance, Size
  18. Metaphorical Blinkers Image CC-BY-SA 2.0 Pete Markham Metaphors We Live

    By, Lakoff and Johnson, 1980. “In allowing us to focus on one aspect of a concept, a metaphorical concept can keep us from focusing on other aspects of the concept that are inconsistent with the metaphor.”
  19. How we describe a system affects how we plan to

    build it Publication Payment Licensing Decision Peer review Reviewer invitation Quality check Manuscript Submission Rejection Rejection A linear timeline, led to linear development and a big-bang release of all functionality
  20. Conway's Law Any organization that designs a system (defined broadly)

    will produce a design whose structure is a copy of the organization's communication structure. – Melvin Conway
  21. Conway's Law rephrased If you have four groups working on

    a compiler, you'll get a four-pass compiler. – Eric S. Raymond
  22. Conway's Law rephrased If you have four groups working on

    a compiler, you'll get a four-pass compiler. – Eric S. Raymond
  23. Conway's Law rephrased If you have four groups working on

    a compiler, you'll get a four-pass compiler. – Eric S. Raymond
  24. Conway's Law rephrased If you have four groups working on

    a compiler, you'll get a four-pass compiler. – Eric S. Raymond A metaphor
  25. Summary ❖ Metaphor helps and hinders ❖ Figurative metaphor is

    technical debt ❖ Cognitive metaphor is inescapable ❖ Metaphor precedes Conway's Law