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Technical Debt

Technical Debt. CS 510 Software Engineering Supannika Koolmanojwong. Outline. What is Technical Debt? Technical Debt Patterns Technical Debt Calculation & Estimation Technical Debt – Industrial perspective. Technical Debt Example.

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Technical Debt

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  1. Technical Debt CS 510 Software Engineering Supannika Koolmanojwong

  2. Outline What is Technical Debt? Technical Debt Patterns Technical Debt Calculation & Estimation Technical Debt – Industrial perspective

  3. Technical Debt Example “Guys, we don’t have time to dot every I and cross every t on this release. Just get the code done. It doesn’t have to be perfect. We’ll fix it after we release.” “We don't have time to reconcile these two databases before our deadline, so we'll write some glue code that keeps them synchronized for now and reconcile them after we ship.” Ref: Steve McConnell – ICSE 2013

  4. Total cost of ownership ‪www.comindwork.com • a financial estimate whose purpose is to help consumers and enterprise managers determine direct and indirect costs of a product or system. • including the costs to research, develop, acquire, own, operate, maintain, and dispose of a system

  5. Total Cost of Software Ownership www.dtbusiness.com ‪newtecharticles.com

  6. Potential total cost of ownership • HW and SW • Network • Server • Workstation • Installation & integration • Purchasing research • Warranties and licenses • License tracking - compliance • Migration expenses • Risks: susceptibility to vulnerabilities, availability of upgrades, patches and future licensing policies, etc. • Infrastructure • Electricity • Testing costs • Downtime, outage and failure expenses • Diminished performance • Security (including breaches, loss of reputation, recovery & prevention) • Backup and recovery process • Technology training • Audit • Insurance • IT personnel • Replacement • Future upgrade or scalability expenses • Decommissioning

  7. Common causes of technical debt Business pressures Lack of process or understanding Lack of building loosely coupled components (hard-coded) Lack of documentation Parallel Development Delayed Refactoring http://en.wikipedia.org/wiki/Technical_debt

  8. Single System Development Perspective Choices driven by potential • Market share • Future opportunities • Technical debt • Cost of failure to provide needed capability

  9. CodeSmell Deficit programming Code Debt Toxic Code Technical Debt Software Decay coined by Ward Cunningham Design Debt Technical Inflation

  10. Ref: ZadiaCodabux and Byron J. Williams. Managing Technical Debt: An Industrial Case Study

  11. Technical Debt Observations“Agile Project Management”, Jim Highsmith, second edition

  12. Types of Debt“Managing Software Debt: Building for Inevitable Change”, Chris Sterling • Technical Debt • These are activities that a team or team members choose not to do well now and will impede future development if left undone • Quality Debt • There is a diminishing ability to verify the functional and technical quality of software • Configuration Management Debt • Integration and release management becomes more risky, complex and error-prone • Design Debt • The cost of adding features is increasing toward the point where it is more than the cost of writing from scratch. • Platform Debt • The availability of people to work on software changes is becoming limited or cost-prohibitive. www.psmsc.com

  13. Technical Debt “is a measure of how untidy or out-of-date the development work area for a product is” Not the deferred requirements http://www.c2.com/cgi/wiki?TechnicalDebt

  14. Technical Debt http://petdance.com/perl/technical-debt “I don’t know what happened, I just changed one line” “We can’t upgrade, It will break” “We can’t upgrade the code, we don’t have time” “We can’t upgrade the code, no one understands it” “Just put in the comment XXX, we will do it later” “Just put in the TODO comment”

  15. Technical Debt • intentional technical debt • cost to taking short cuts • unintentional technical debt • making mistakes • Conscious decision to optimize for the “present” rather than the “future” • cost of not dealing with these short cuts and mistakes will increase over time.  Read more: http://www.javacodegeeks.com/2012/02/technical-debt-how-much-is-it-really.html#ixzz1phjvB5A9

  16. http://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdfhttp://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdf

  17. http://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdfhttp://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdf

  18. http://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdfhttp://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdf

  19. http://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdfhttp://pkruchten.files.wordpress.com/2011/10/kruchten-111027-techdebt.pdf

  20. Outline What is Technical Debt? Technical Debt Patterns Technical Debt Calculation & Estimation Technical Debt tool – Industrial perspective

  21. Technical DebtArchitecture or the platform technology mistake Read more: http://www.javacodegeeks.com/2012/02/technical-debt-how-much-is-it-really.html#ixzz1phnGFlUV Scalability, reliability Foundations are poorly design you don’t find out until too late (operations phase) no choice but to start again or rewrite big chunk to keep it working

  22. Technical DebtError-prone code Read more: http://www.javacodegeeks.com/2012/02/technical-debt-how-much-is-it-really.html#ixzz1phnGFlUV http://petdance.com/perl/technical-debt/technical-debt.007.html “ .. If I change X, it is going to break Y, I think ..” “ Don’t touch that code, last time we did, we spent a week fixing it…” 20% of the code where 80% of bugs are found Hard to understand Dangerous to change because done poorly one in the first place Not rewriting this code is one of the most expensive mistakes that developers make

  23. Technical DebtNot easily tested Read more: http://www.javacodegeeks.com/2012/02/technical-debt-how-much-is-it-really.html#ixzz1phnGFlUV “ .. I thought we had a test for that ..” Don’t have good automated tests Tests keep falling apart when you change the code Testing costs tend to go up over time as you write more code

  24. Technical DebtCode that mysteriously works Read more: http://www.javacodegeeks.com/2012/02/technical-debt-how-much-is-it-really.html#ixzz1phnGFlUV nobody is sure how or why Might be written by the geek who left the company if nobody on the team understands it, it’s a time bomb

  25. Technical DebtOthers Read more: http://www.javacodegeeks.com/2012/02/technical-debt-how-much-is-it-really.html#ixzz1phnGFlUV • Forward and backward compatibility • Short term debt • Duplicate, copy-and-paste code • How many ? Trackable ? • Hard coding • Out of date documentation • “We just lost the drive, where are the backups” • If nobody is using it, get rid of it. If people are using it, why isn’t it up to date?

  26. Development Cost(Perfect World) % Effort per Phase Analysis Test Integration Design Implementation

  27. Typical Defect Profiles Classification of Defects Design Defects Implementation Defects Integration Defects Analysis Test Integration Design Implementation Defect Insertion Defect detection & Removal

  28. Development Cost(Real World) % Effort per Phase Analysis Test Integration Design Implementation

  29. Development Cost % Effort per Phase Analysis Test Integration Design Implementation Real world Perfect World

  30. Development Cost Technical Debt? Technical Debt? % Effort per Phase Technical Debt? Technical Debt? Analysis Test Integration Design Implementation Real world Perfect World

  31. Development Cost Technical Debt? % Effort per Phase Technical Debt? Analysis Test Integration Design Implementation Real world Perfect World

  32. COTS Integration % Effort per Phase Technical Debt? Analysis Test Integration Design Implementation Real world Perfect World

  33. Outline What is Technical Debt? Technical Debt Patterns Technical Debt Calculation & Estimation Technical Debt – Industrial perspective

  34. Financial debt vsTechnical Debt http://martinfowler.com/bliki/TechnicalDebt.html

  35. Technical Debt Cost Estimation Principal = Repair Effort Interest = Maintenance Effort [Nugroho et al 2011] [Curtis et al 2012] Ref: Nugroho et al 2011, An Empirical Model of Technical Debt and Interest, MTD 2011 Ref: Curtis e al 2011, Estimating the Principal of an Application's Technical Debt. IEEE Software

  36. 700 applications • 158 organizations • 357 MLOC • No sample less than 10KSLOC Conservative - Assume all violations would be fixed within one hour Weighted - varied the hours needed for fixing within each severity category, More realistic - based on data observed in several IT organizations. Ref: Curtis e al 2011, Estimating the Principal of an Application's Technical Debt. IEEE Software

  37. Average Technical Debt per LOC = $3.61 Ref: Curtis e al 2011, Estimating the Principal of an Application's Technical Debt. IEEE Software

  38. Ref: Curtis e al 2011, Estimating the Principal of an Application's Technical Debt. IEEE Software

  39. Technical Debt within each technology http://www.castsoftware.com/research-labs/technical-debt-estimation

  40. Outline What is Technical Debt? Technical Debt Patterns Technical Debt Calculation & Estimation Technical Debt – Industrial perspective

  41. Sonar Mainly manage the software quality SQALE – Software Quality Assessment based on Lifecycle Expectations

  42. Nemo - An open source tool – by sonarhttp://nemo.sonarqube.org

  43. Sonar – SQALE plug-inhttp://www.sonarsource.com/products/plugins/governance/sqale/

  44. Developers’ 7 Deadly Sins Bad Distribution of Complexity Duplications Lack of Unit Tests No Coding Standards Not Enough or Too Many Comments Potential Bugs Spaghetti Design http://docs.codehaus.org/display/SONAR/Developers%27+Seven+Deadly+Sins

  45. Developers’ 7 Deadly Sins Bad Distribution of Complexity Duplications http://docs.codehaus.org/display/SONAR/Developers%27+Seven+Deadly+Sins

  46. Developers’ 7 Deadly Sins Lack of Unit Tests No Coding Standards http://docs.codehaus.org/display/SONAR/Developers%27+Seven+Deadly+Sins

  47. Developers’ 7 Deadly Sins • Not Enough or Too Many Comments (time consuming maintenance) • Documented complex or not straightforward pieces of code • Readable unit tests scenarios that will help the developers understand the code • Documented API that will help external developers understand how to use those API • Respect of coding standard such as naming conventions • Potential Bugs http://docs.codehaus.org/display/SONAR/Developers%27+Seven+Deadly+Sins

  48. Developers’ 7 Deadly Sins • Spaghetti Design • Hunting for cycles • Checking your own architecture rules • Managing your libraries • Checking the single responsibility principle with LCOM4 (Lack of Cohesion of Methods) • RFC (Response for Class) – checking coupling (complexity of class in terms of method calls) http://docs.codehaus.org/display/SONAR/Developers%27+Seven+Deadly+Sins

  49. x = = x http://www.moovweb.com/blog/technical-debt-infographic/

  50. Back up charts

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