Software Complexities

During the life cycle of a system there can be vast amounts of internal and external influences that can lead to over complicated processes, infrastructure, design architectures, and ugly code. Decisions are sometimes made that can make software costly and difficult to maintain. The more complicated the software is the more time it takes to build, test and deploy.
What are the key areas that make software so complicated and can we identify these before they get out of hand?

Transcript

1. 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
2. Software Complexities Peter Fisher BSC MBCS Software Complexities
3. Peter Fisher BSC MBCS Software Complexities Try and answer why Ask who/what is to blame The key to simplicity
4. Peter Fisher BSC MBCS Software Complexities The Developer The Client The End User Who/what is to blame The Technology
5. Peter Fisher BSC MBCS Software Complexities The Developer The Client The End User Who/what is to blame The Technology BLAME ALL THE THINGS
6. Peter Fisher BSC MBCS Software Complexities Why is software development complex?
7. Peter Fisher BSC MBCS Software Complexities Software is invisible Software cannot be visualised
8. Peter Fisher BSC MBCS Software Complexities Software is constantly changing
9. Peter Fisher BSC MBCS Software Complexities Why is complexity so bad?
10. Peter Fisher BSC MBCS Software Complexities Complexity leads to Communication issues Product flaws, cost and delays
11. Peter Fisher BSC MBCS Software Complexities Complexity leads to Difficulty enumerating Less understanding of the possible states
12. Peter Fisher BSC MBCS Software Complexities Complexity leads to Ugly code Hard to integrate, maintain and extend
13. Peter Fisher BSC MBCS Software Complexities Complexity leads to The unknown Security breaches, re writes and over abstraction
14. Peter Fisher BSC MBCS Software Complexities Complexity leads to Fickle business decisions Loss of data integrity, high barrier of entry and increased personnel turnover
15. Peter Fisher BSC MBCS Software Complexities Complexity is the most common difficulty but not all complexity is inevitable
16. Peter Fisher BSC MBCS Software Complexities The Mythical Man-Month No Silver Bullet Frederick P Brooks Jr
17. Peter Fisher BSC MBCS Software Complexities Essential complexity Vs Accidental complexity
18. Peter Fisher BSC MBCS Software Complexities Essential complexity
19. Peter Fisher BSC MBCS Software Complexities Nice to haves are only nice if they enhance the core functionality
20. 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!
21. 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
22. Peter Fisher BSC MBCS Software Complexities - Testing (code level, UAT, Load, Integration etc..) - Documentation - Training - Designing - Development - Maintenance Features require
23. Peter Fisher BSC MBCS Software Complexities Have a meeting every time a essential feature is added
24. Peter Fisher BSC MBCS Software Complexities Celebrate every time a essential feature is removed
25. 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?
26. Peter Fisher BSC MBCS Software Complexities How many essential features do you think Twitter has?
27. 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
28. Peter Fisher BSC MBCS Software Complexities Accidental complexity
29. Peter Fisher BSC MBCS Software Complexities Steaming pile of source code Box fresh shiny toy - Magpie like New Project Legacy Project
30. Peter Fisher BSC MBCS Software Complexities New Project - You make ALL the accidents - High risk of over generalising the requirements - Keep It Simple Stupid
31. 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
32. Peter Fisher BSC MBCS Software Complexities Accident + Time = Steaming Pile Of Source Code A + T = S + =
33. Peter Fisher BSC MBCS Software Complexities The keys to simplicity
34. 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”
35. Peter Fisher BSC MBCS Software Complexities Don’t Repeat Yourself Don’t Over Abstract Don’t Over Generalise
36. 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
37. Peter Fisher BSC MBCS Software Complexities Buy versus build
38. Peter Fisher BSC MBCS Software Complexities Software should be grown not built
39. 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.”
40. Peter Fisher BSC MBCS Software Complexities Getting simplicity right is complicated
41. Peter Fisher BSC MBCS Software Complexities Thank you. give feedback https://joind.in/talk/4503f