Software Complexities - Speaker Deck

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How to put your Docker image on a diet Peter Fisher BSC MBCS Host of the How To Code Well channel Author of Docker In Motion Freelance web & mobile applications developer youtube.com/howtocodewell 40% off code dockphpsc From Manning Publications Software Complexities

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Software Complexities Peter Fisher BSC MBCS Software Complexities

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Peter Fisher BSC MBCS Software Complexities Try and answer why Ask who/what is to blame The key to simplicity

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Peter Fisher BSC MBCS Software Complexities The Developer The Client The End User Who/what is to blame The Technology

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Peter Fisher BSC MBCS Software Complexities The Developer The Client The End User Who/what is to blame The Technology BLAME ALL THE THINGS

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Peter Fisher BSC MBCS Software Complexities Why is software development complex?

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Peter Fisher BSC MBCS Software Complexities Software is invisible Software cannot be visualised

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Peter Fisher BSC MBCS Software Complexities Software is constantly changing

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Peter Fisher BSC MBCS Software Complexities Why is complexity so bad?

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Peter Fisher BSC MBCS Software Complexities Complexity leads to Communication issues Product ﬂaws, cost and delays

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Peter Fisher BSC MBCS Software Complexities Complexity leads to Difﬁculty enumerating Less understanding of the possible states

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Peter Fisher BSC MBCS Software Complexities Complexity leads to Ugly code Hard to integrate, maintain and extend

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Peter Fisher BSC MBCS Software Complexities Complexity leads to The unknown Security breaches, re writes and over abstraction

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Peter Fisher BSC MBCS Software Complexities Complexity leads to Fickle business decisions Loss of data integrity, high barrier of entry and increased personnel turnover

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Peter Fisher BSC MBCS Software Complexities Complexity is the most common difﬁculty but not all complexity is inevitable

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Peter Fisher BSC MBCS Software Complexities The Mythical Man-Month No Silver Bullet Frederick P Brooks Jr

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Peter Fisher BSC MBCS Software Complexities Essential complexity Vs Accidental complexity

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Peter Fisher BSC MBCS Software Complexities Essential complexity

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Peter Fisher BSC MBCS Software Complexities Nice to haves are only nice if they enhance the core functionality

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Peter Fisher BSC MBCS Software Complexities Write down your essential features Include a justiﬁcation for each essential feature Will 80% of the system function without the essential feature? - If so then it isn’t essential!

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Peter Fisher BSC MBCS Software Complexities Every time a feature is added the level of complexity is increased across the entire development life cycle of the project

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Peter Fisher BSC MBCS Software Complexities - Testing (code level, UAT, Load, Integration etc..) - Documentation - Training - Designing - Development - Maintenance Features require

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Peter Fisher BSC MBCS Software Complexities Have a meeting every time a essential feature is added

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Peter Fisher BSC MBCS Software Complexities Celebrate every time a essential feature is removed

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Peter Fisher BSC MBCS Software Complexities Menu A has 100 options Menu B has 15 options Which one is more complicated to the customer, waiter and chef?

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Peter Fisher BSC MBCS Software Complexities How many essential features do you think Twitter has?

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Peter Fisher BSC MBCS Software Complexities If you are starting a project from scratch then ONLY the essential features should be included in the ﬁrst release

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Peter Fisher BSC MBCS Software Complexities Accidental complexity

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Peter Fisher BSC MBCS Software Complexities Steaming pile of source code Box fresh shiny toy - Magpie like New Project Legacy Project

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Peter Fisher BSC MBCS Software Complexities New Project - You make ALL the accidents - High risk of over generalising the requirements - Keep It Simple Stupid

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Peter Fisher BSC MBCS Software Complexities - If you can, try to Decouple, Downsize and Defuse the complexity from the wider system - “If it isn’t broke don’t ﬁx it” This doesn’t make sense in software development Legacy Project

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Peter Fisher BSC MBCS Software Complexities Accident + Time = Steaming Pile Of Source Code A + T = S + =

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Peter Fisher BSC MBCS Software Complexities The keys to simplicity

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Peter Fisher BSC MBCS Software Complexities Brooks, F., 1995. The Mythical Man-Month: Essays on Software Engineering. 2nd ed. University of North Carolina at Chapel Hill: Addison-Wesley. “Software entities are more complex for their size than perhaps any other human construct, because no two parts are alike”

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Peter Fisher BSC MBCS Software Complexities Don’t Repeat Yourself Don’t Over Abstract Don’t Over Generalise

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Peter Fisher BSC MBCS Software Complexities Code that glues two systems together is often easier to write and maintain compared to writing a monolith from scratch

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Peter Fisher BSC MBCS Software Complexities Buy versus build

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Peter Fisher BSC MBCS Software Complexities Software should be grown not built

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Peter Fisher BSC MBCS Software Complexities Brooks, F., 1995. The Mythical Man-Month: Essays on Software Engineering. 2nd ed. University of North Carolina at Chapel Hill: Addison-Wesley. “We still make syntax errors, to be sure; but they are fuzz compared to the conceptual errors in most systems. If this is true, building software will always be hard. There is inherently no silver bullet.”

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Peter Fisher BSC MBCS Software Complexities Getting simplicity right is complicated

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Peter Fisher BSC MBCS Software Complexities Thank you. give feedback https://joind.in/talk/4503f