Your Software is Mission Critical

If an autopilot fails, or a weapon system malfunctions, lives can and will be lost. As a result, significant checks, practices and concepts go into designing the software for such systems. But the code we, as developers in a wide range of jobs and fields, write can be just as critical - a delayed benefits submission because of a server error causes somebody to become homeless; a mistake on an immigration system causes a family to be deported; a misrouting of a delivery driver causes a car crash.

As developers we should explore the culture around what we build - move fast and break things doesn't work if you're dealing with real people's real lives. Are there lessons of software development, design, project management, that we can learn from "mission critical" software production, and apply to our "normal" development projects that can ultimately save frustration, jobs and even lives in the process?

Transcript

1. preparing to
   mess with Texas
   1
   …
   

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2. Hello!
   I’m Mike Lehan
   CTO StuRents.com
   Software engineer
   @m1ke
   2
   

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3. Your Software is
   Mission Critical
   

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6. “
   People were noticing that there was
   something about these systems that had an
   impact on their lives.
   The Age of Algorithmic Anxiety, Kyle Chayka for The New Yorker
   6
   

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10. Move fast and break things.
    Unless you are breaking stuff,
    you are not moving fast enough.
    Mark Zuckerberg
    

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11. We are the people who
    build software
    11
    

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13. Why “Mission Critical”?
    13
    

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16. “But I don’t build
    autopilots”
    16
    

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17. Our world is dominated by software
    Much of our ability to operate critical infrastructure
    depends on technology
    ▫ Healthcare
    ▫ Finance
    ▫ Defence
    ▫ Transportation
    17
    

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18. Our world is dominated by software
    So does our ability to conduct day to day life…
    ▫ Interacting with government
    ▫ Paying our bills
    ▫ Buying food
    ▫ Education
    18
    

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19. Our world is dominated by software
    … and to completely ignore it
    ▫ Cat gifs
    ▫ Social media
    ▫ Twenty seven different streaming services
    19
    ▫ More cat gifs
    

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21. So, what’s the problem?
    21
    People
    Anxiety
    Loss
    Stress
    Development
    Mistakes made
    in software
    development
    Operation
    Errors in live
    usage of the
    software
    

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22. “
    A computer lets you make more mistakes,
    faster, than any invention in human history –
    with the possible exceptions of handguns
    and tequila.
    Mitch Ratcliffe, Technology Review April 1992
    22
    

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24. Some clarifications
    ▫ How we build software can have unintended negative impact
    ▫ Not about whether the intent of the software is good or bad
    24
    ▫ Grey area between badly written software,
    and bad business practices
    

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25. It’s our responsibility to
    get this right.
    How do we do that?
    25
    

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26. Testing
    1
    

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27. 27
    The “mission critical” way
    FAA DO-178C (aircraft software certification)
    “processes (and their concrete activities) must have well
    defined entry and exit criteria, according to DO-178C,
    and a project must show that it is respecting those
    criteria as it performs the activities in the process”
    

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28. “Say what you are going
    to do before you do it”
    28
    

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29. 29
    Test driven development
    ▫ Write a test for the expected outcome
    ▫ Write some code to pass the test
    ▫ Make the code “nicer” whilst ensuring the test still passes
    (refactoring)
    What about legacy projects?
    

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32. 32
    Ways to improve coverage
    ▫ Collecting metrics
    ▫ PR targets (start out using baselines)
    ▫ Avoid covering brittle features
    ▫ … a different approach - static analysis
    

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33. 33
    The “mission critical” way
    Astree - verification of absence of runtime error
    “Astree proved absence of runtime errors in A380 software
    in 2004, prior to maiden flight in 2005”
    By verifying all paths of a program, we can guarantee
    freedom from errors
    

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34. 34
    Psalm
    

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36. So, what’s the benefit?
    36
    People
    Can rely on
    software that
    always does
    the right thing
    Development
    Tests ensure
    code changes
    don’t break
    applications
    Operation
    Systems build
    trust by being
    more resilient
    

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37. Design
    2
    

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38. 38
    The “mission critical” way
    (once again) FAA DO-178C (aircraft software certification)
    “Once an activity within a process has been defined, it is generally
    expected that the project respect that documented activity within its
    process”
    

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41. Design shouldn’t just
    stop when we get to
    the code
    41
    

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42. “
    To create a supple, knowledge- rich design calls for a
    versatile, shared team language, and a lively
    experimentation with language that seldom
    happens on software projects.
    Domain Driven Design, Eric Evans
    42
    

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43. Make the impossible,
    inexpressible
    43
    

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50. So, what’s the benefit?
    50
    People
    Have their needs
    met by software
    that understands
    them
    Development
    Good design
    means we know
    why we build
    what we build
    Operation
    Well designed
    software
    understands
    the use case
    

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51. Time
    Money
    Diversity
    Management
    3
    

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52. Time
    Money
    Diversity
    Management
    3
    Time
    Money
    Diversity
    Management
    Humans
    

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53. “
    A recent study published by the AI Now Institute of
    New York University concluded that a “diversity
    disaster” has resulted in flawed AI systems that
    perpetuate gender and racial biases.
    Why Diversity In AI Is So Important, Maria Klawe for Forbes
    53
    

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54. 54
    Factors often beyond our control
    ▫ Who manages us?
    ▫ Who’s buying it?
    ▫ How will they react to it?
    ▫ How can we influence this?
    

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56. 56
    Diverse teams
    ▫ Complex software is multi-faceted; and teams that build it
    should be as well
    ▫ Blind spots in development lead to flaws in design &
    implementation - representative teams address this
    ▫ The complexity and ingenuity of humans, solving problems
    for other humans
    

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57. 57
    diverseandequal.com
    

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58. 58
    Developers solve problems
    ▫ Using code is just one way to do it
    ▫ Apply software principles more broadly:
    ▫ Is it reproducible?
    ▫ Does it “work on my machine”?
    ▫ Have you turned it off and on again?
    

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59. In Conclusion
    

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60. “
    Software is eating the world.
    Marc Andreessen, 2011
    60
    

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61. 61
    Our software is mission critical
    ▫ Testing - prioritise doing tests, even if they are imperfect
    ▫ Design - consider your approach, codify your solutions
    ▫ Humans - think about the people who use, influence and
    create your software
    ▫ Be humble - learn new ways to do things, make good plans,
    hold them lightly
    

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63. “
    The trouble was the familiar one:
    too much power, too little knowledge.
    The fault was mine…
    “Damage” by Wendell Berry
    63
    

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64. 64
    Thanks!
    Agree/disagree/ambivalent?
    Let me know: @m1ke
    joind.in/talk/d2d83
    

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