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Technical Debt: Do Not Underestimate The Danger
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Technical Debt: Do Not Underestimate The Danger


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This is the slides of my latest talk about the "technical debt" concept.

This is the slides of my latest talk about the "technical debt" concept.

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  • 1. Do not underestimate the danger technical Lemİ Orhan ERGİN Principal Software Engineer @ Sony debt @lemiorhan
  • 2. Lemİ Orhan Ergİn Principal Software Engineer at Sony has worked in Tüsside, BYM, GittiGidiyor/eBay and Sony as lead developer, team leader, technical coordinator and scrum master got CSM certificate from Jim Coplien year as Scrum Master sprints in 4 years as team member and scrum master experienced in agile transformation and building agile culture in teams & organizations 2001 2013 2009 1 56 agile CSM, PSM1
  • 3. financial debt and the metaphor
  • 4. expensive DEBTsin every second of our lifeWe incur Living is
  • 5. taxes gas fuel water phone electricity rent credit cards cabletv tuition TOLLS mortgageschool payments transportation Holidays INTERNET 3g/4G municipal services shopping communication food health entombment Parking
  • 6. Financial debtis not always a bad thing. It lets us buy what we want or what we need and keep us live at some level.
  • 7. Financial debtis dangerous if the incurred interest and the debt itself are not payed
  • 8. Financial debt is a silent killer
  • 9. Financial debt hides problemsand leads to other problems
  • 10. technical debtis a metaphor developed by Ward Cunningham in 1992 to communicate problems due to“developing not in the right way” with non-technical stakeholders. met·a·phor noun ˈme-tə-ˌfȯr also -fər a word or phrase for one thing that is used to refer to another thing in order to show or suggest that they are similar
  • 11. deficit Enron financing paying the principal debt Interest on the debt bankruptcy borrowing money Intertest on the loan Inflation financial burden very similar technical debt is to financial debt
  • 12. the cost
  • 13. technical debt costs money, time and effort to stakeholders, developers, companies, even to economies
  • 14. most companies have to spend 80% of their software development budget maintaining code Aaron Erickson, “ ”
  • 15. U.S. Air Force pulls plug on ERP project after blowing through $1 billion chris kanaracus, “ ”
  • 16. we don’t know how much technical debt is really costing us Jim bird, “ ”
  • 17. Technical debt is like smoking addiction. Once you start hacking your code, the code asks for more. you never know what that will cost in the future. Lemİ Orhan ERGİN, “ ”
  • 18. High amount of Technical Debt is #1 impediment to teams being agile Dan Rawsthorne “ ”
  • 19. Sufficient amount of messy code may bring whole Engineering department to a stand-still Sven Johann & Eberhard Wolff, Infoq “ ”
  • 20. the description
  • 21. 2 ways of doing things
  • 22. clean and smart way takes longer to implement but make changes easier in the future
  • 23. quick and dirty way get your features sooner, but make the future changes very hard
  • 24. why should the sponsors of a project accept higher costs ? Question:
  • 25. why should the sponsors spend money on features that don’t deliver business value ? Question:
  • 26. Living with technical debt might work perfectly for customers if it delivers the desired business value Answer:
  • 27. but this will lead an uncontrollable codebase, extremely specialized developers and to an inflexible product
  • 28. Shipping firsttime code is like going into debt
  • 29. a little debt speeds development as it is paid back with a rewrite
  • 30. It’s a question of Pay me now or Pay me later
  • 31. good or bad
  • 32. ... if you have strategic design decisions. It allow rapid delivery to elicit quick feedback and correct design. However, clean code is required to pay back debt therefore the code sould be refactored ıncurring technical debt is a good idea
  • 33. ... if principal amount and interest is smaller than the yield of investment. Sometimes, you don't have to pay back the debt, it is pointless if the code won't be touched again ıncurring technical debt is a good idea
  • 34. ... because having messy code and cutting quality slows you down in reality. And you must generate more mess to keep up. Do you ask permission to do your job correctly???? ıncurring technical debt is a bad idea
  • 35. extend the metaphor
  • 36. similarities with financial debt Every minute spent on not-quite-write code counts as interest on the debt Interest Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 37. similarities with financial debt Refactoring is like paying off the principal debt paying the principal debt Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 38. similarities with financial debt Neglecting the design is like borrowing money borrowing money Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 39. similarities with financial debt Bankruptcy refers to a situation of overwhelming debt interest, whereby progress is halted and a complete rewrite is necessary bankruptcy Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 40. similarities with financial debt It occurs when the current level of technology is old enough to lose compatibility with the industry technical Inflation Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 41. similarities with financial debt It represents technical frauds undermine ROIs Enron Financing Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 42. similarities with financial debt Throw away prototypes, retired products and complete failures on will-not-be-used components does not have to be repaid amnesty Image by Martin Schoeller from “Identical: Portraits of Twins” book
  • 43. the Symptoms
  • 44. the loss of productivity We cannot measure productivity, that's why we can't really see real the true effect of technical debt and losing motivation and morale
  • 45. Increase in testing If the team does the same tests again and again on every release or testing takes too much time, the debt seems to be in critical level. the death by manual testing
  • 46. Postponed stories in releases Postponed releases It becomes harder to catch the deadlines. An increase on the postponed releases rate is an indicator. being not ready to go
  • 47. Code duplication Code duplication leads to update anomalies, purpose masking and issues on understanding code copy & Paste programming
  • 48. Low code coverage 100% coverage is the asymptotic target. Below 75% indicates serious problems. not knowing how sW behaves
  • 49. Increase in bugs The increase in number of bugs directly shows the decrease of quality and too much support cases
  • 50. heavy stress on appoaching deadlineS The team is under heavy stree at the end of releases or when the deadlines are approaching
  • 51. being scared of changing anything Software is so brittle that developers are scared of changing anything in the code not to break. Adding new features starts to cost more and more.
  • 52. Evil hacks wrong design It’s hard to detect the debt in advance, but any hacks and workarounds could cause issues in the future
  • 53. wrong choice of technology Not the most mature, not the newest, not the simplest... Choosing the cheapest-to-adapt is the key to pay the debt.
  • 54. unreadable code Developers spend 80% of development time for reading code. You cannot build if you cannot understand. hard to understand what happens
  • 55. decreased velocity Decreased team velocity is a good indicator for possible impediments that slows the team down even if nothing has changed
  • 56. Using old libraries Softwares age and cause technical debt by time. Maintenance costs are the main expenditure item. and technologies
  • 57. Reports of Sonar Sonar Reports Softwares age and cause technical debt by time. Maintenance costs are the main expenditure item. with technical debt plugin
  • 58. bad smells The indicator of weaknesses in design that may be slowing down development or increasing the risk of bugs or failures in the future “Only he knows can change this part” “Lets copy & paste this code” “If I touch, everything will break” “Too many TODOs or FIXMEs in the code”
  • 59. 36 classic mistakes Making mistakes is inevitable. Only experienced software developers realize when they're making mistakes. outlined in McConnell's Rapid Development
  • 60. the types by scope
  • 61. unavoidable debt Usually unpredictable and unpreventable and the team has no fault on that Due to legal issues, we have to rewrite some of the components “ ”
  • 62. Strategic debt Long term debt, usually incurred proactively I want to be the first in the market“ ”
  • 63. tactical debt It’s different that strategic by the reactive manner for the short term We don't have time to implement in the right way, just a hack. We'll fix later. “ ”
  • 64. Incremental debt Hundreds or thousands of small shortcuts, like credit card debt We have to do quick hacks and dirty solutions to catch the deadline “ ”
  • 65. INADVERTENT (naive) debt It occurs due to irresponsible behavior or immature practices on the part of the people involved We have to build the software product with inexperienced newbies “ ”
  • 66. the types by content
  • 67. Design & architectural Debt Shortcuts and shortcommings Long and detailed upfront designs Sub-optimal solutions
  • 68. code quality Debt Short time between failures Severe defect count Every hack, work around, bad piece of code builds Unnecessary code duplication and complexity
  • 69. testing Debt Missing automated tests Too much time spending for regression testing
  • 70. Knowledge distribution and documentation debt Only few people knows the system When all key people left the organization, the debt becomes extremely high
  • 71. Environmental Debt Problems in development related processes Issues in hardware, infrastructure, supporting apps Having too many manual operational tasks
  • 72. Monetary cost Developer’s time is expensive No developer enjoys to work on brittle and complicated code That leads turnovers and it is one of the real economic costs of technical debt
  • 73. the stakeholders
  • 74. customers Annoyed by bugs, missing features, slow lead times and expensive costs
  • 75. helpdesk Additional costs
  • 76. operations team Frequent patches and fixes
  • 77. management Annoyed due to bugs, delays, costs and security issues
  • 78. developers No one wants to develop bad code No one wants to take over bad work of others
  • 79. the strategic design
  • 80. A system can't have the same high level of quality throughout the system strategic design The team can choose which parts will have high quality or kept as low quality Consumer understands quick & dirty solutions lead to debt Understanding Strategic Design leads to better decisions from stakeholders
  • 81. fixing the debt
  • 82. Merciless refactoring
  • 83. fast automation
  • 84. share knowledge knowledge decays fast
  • 85. slow down to go fast
  • 86. clean code principles clean, readable and simple code
  • 87. clear definition of done showing us how to avoid incurring debt
  • 88. key engineering practices Pair Programming Test Driven Development Continuous Integration 10 min Builds Refactoring Automated unit tests etc. these should always directly associated with a requirement
  • 89. test driven development Pre-release defect density decreased 40-90% relative to similar products that do not use TDD Initial development time increased 15-35% after TDD
  • 90. fail fast Peer Review Code Review Don't leave all testing to the last phase
  • 91. Limit work-in-progress
  • 92. fix constantly
  • 93. Monitor your debt Code coverage: Monitor trends, not points Cyclomatic complexity: Number of branches in code Coupling: Interconnectedness of systems
  • 94. clean constantly
  • 95. fix root causes
  • 96. Follow the Boy Scout Rule quality is your responsibility
  • 97. never make intentional mess
  • 98. Never ask permission to do your job correctly
  • 99. The Payment strategies From Frank Buschmann
  • 100. debt repayment Refactor or replace code
  • 101. debt conversion Replace the current solution with a "good but not perfect" solution
  • 102. just pay the interest Live with the code Refactoring is more expensive than the work with bad code End-of-life software or will-be-retired software
  • 103. The Payment Approaches
  • 104. Minimal Iteration Debt Payment Half a day in a week
  • 105. Technical Backlog Debt is made visible and clear for everbody Cost per task is trackable No mixture between technical and feature tasks adv.disadv. 2 backlogs and hard to prioritize Customers may not understand the real benefits of a tech task Very expensive changes must always a business reason
  • 106. buffer tasks for refactoring 10% of the team's time
  • 107. clean-up releases
  • 108. The measurment
  • 109. time investment is actually worth it it is important to decide that
  • 110. even impossible to predict The effect of bad code quality for future requirements is difficult
  • 111. The delta from ideal Errors & warnings Code duplication Code coverage Gut feeling in large apps, the measure is basically useless
  • 112. Story Probing The assumption is that technical debt increases the estimate
  • 113. formulas to guess the debt There are many formulas proposed and used
  • 114. Estimate the cost of a failure and then multiply by the probability it will occur Technical debt is the cost of implementing the required redundancy
  • 115. the conclusion
  • 116. you got the red pill Understanding technical debt will let you, your team, the business and the stakeholders make better decisions
  • 117. Technical Debt 1 Billion Dolar Fail Evluation with Sonar 36 Classic Mistakes Calculating the ocost
  • 118.
  • 119. Lemİ orhan ergİn @lemiorhan @lemiorhan @lemiorhan LINKEDINTWITTERSLIDESHAREBLOG Principal Software Engineer @ Sony Founder & Author @