1. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 1 Informatics 43 Introduction to Software Engineering Lecture 8-2 November 19, 2015 Emily Navarro Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited.

2. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 2 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

3. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 3 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

4. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 4 Processes as a Remedy Software is engineered via a defined process – Cover all steps from initial idea and requirements to delivery, maintenance, and final retirement – Make sure we do the right things/we do things right – Make sure we do not forget to do anything – Different processes for different kinds of software Not a silver bullet [Brooks “No Silver Bullet”] – Software is still intrinsically difficult to deal with – Processes help, but cannot guarantee anything Remember: People + Processes + Tools  Product

5. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 5 Processes Elements – Activities (“Phases”) – Artifacts Requirements document, design document, code, test cases… – Resources People (their time and their cost) Tools (their time and their cost) Relationships between the elements – Precedence, requires, provides, refines to, … Constraints – Time – Cost – Qualities (repeatable process?)

6. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 6 Software Life Cycle Models Build-and-fix Waterfall Rapid prototyping Incremental Spiral Rational Unified Process (RUP) Open Source Software (OSS) Extreme Programming (XP) Agile A software life cycle model is a high-level process

7. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 7 Software Life Cycle Models Build-and-fix Waterfall Rapid prototyping Incremental Spiral Rational Unified Process (RUP) Open Source Software (OSS) Extreme Programming (XP) Agile A software life cycle model is a high-level process Covered in Lecture 8-1

8. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 8 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

9. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 9 Spiral Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

10. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 10 Each loop through the spiral… Identify a high-risk sub-problem or aspect Resolve the risk (as far as possible) Verify

11. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 11 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

12. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 12 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

13. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 13 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

14. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 14 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

15. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 15 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

16. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 16 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

17. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 17 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

18. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 18 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

19. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 19 Spiral Risk analysis Risk analysis Risk analysis Risk analysis Rapid prototype Specification Design Implementation Verify

20. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 20 Software Risks: Some of Boehm’s Top 10 RiskRisk Management Techniques Personnel shortfallsStaff with top talent, job matching, morale building Unrealistic schedules and budgetsDetailed cost/schedule estimation, reuse, incremental development Developing the wrong software functionsUser surveys, prototyping Continuing stream of software changesInformation hiding, incremental development Shortfalls in externally furnished components Compatibility analysis Shortfalls in externally performed tasksReference checking, competitive design or prototyping Adapted from Hans Schaefer’s “Software Risk Management: A Calculated Gamble”

21. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 21 Full Spiral

22. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 22 So… What is it good for? (strengths) What is it bad for? (weaknesses)

23. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 23 So… What is it good for? (strengths) – Large, expensive, complicated projects – New projects with uncertain, complex requirements What is it bad for? (weaknesses)

24. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 24 So… What is it good for? (strengths) – Large, expensive, complicated projects – New projects with uncertain, complex requirements What is it bad for? (weaknesses) – Small projects – Developers have to be competent at risk analysis

25. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 25 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

26. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 26 Rational Unified Process Influential, best practices of its time (1990s, Object-Oriented SE) More realistic depiction of – The non-discrete nature of SE – The need to have flexibility/adaptability in the process itself – The interplay of Processes Time Various SE activities over time – Much more… Workflows, Activities, Artifacts, Workers… Makes more sense if you are a project manager…

27. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 27 The RUP Model Management Environment Business Modeling Implementation Test Analysis & Design Preliminary Iteration(s) Iter. #1 Phases Process Workflows Iterations Supporting Workflows Iter. #2 Iter. #n Iter. #n+1 Iter. #n+2 Iter. #m Iter. #m+1 Deployment Configuration Mgmt Requirements ElaborationTransitionInceptionConstruction Workflows group activities logically In an iteration, you walk through all workflows

28. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 28 RUP Workflow: Architectural Analysis

29. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 29 RUP Workflow: Analysis & Design

30. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 30 The steps of use-case-analysis

31. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 31 So… What is it good for? (strengths) What is it bad for? (weaknesses)

32. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 32 So… What is it good for? (strengths) – Risk-driven, incremental – Lots of tool support – Provides a lot of guidance What is it bad for? (weaknesses)

33. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 33 So… What is it good for? (strengths) – Risk-driven, incremental – Lots of tool support – Provides a lot of guidance What is it bad for? (weaknesses) – Complicated (need a process expert to implement it)

34. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 34 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

35. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 35 Open-Source Software (OSS): Classic Version Source code is freely available and (usually) re-distributable Many contributors working in a distributed manner – Coders – Bug finders – Documenters – Project leadership – Often volunteers Heavy reliance on software tools – The web and email – Version control and repositories, bug trackers Scales up amazingly well Where do they find the time?

36. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 36 OSS Underlying Philosophy “This is a way to optimize the usage of the work, the value humanity as a whole gets from it. At the cost, of course, of the ability of the producer to capture value.” -Marijn Haverbeke (http://marijnhaverbeke.nl/blog/sustainable-maintenance.html)

37. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 37 OSS Classic: Only Two Phases First, develop the initial version – Usually one or a small number of developers Second, maintain (evolve!) – Users become co-developers (co-maintainers!) – Report and correct defects Corrective maintenance – Enhance and add new functionality Perfective maintenance – Port to a different environment Adaptive maintenance

38. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 38 OSS Success Stories Operating systems – Linux Web browser – Firefox Compiler – gcc Web server – Apache Database – MySQL Development environment – Eclipse

39. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 39 Open Source: The Corporate Version Use open source software – Saves money – Avoids “lock-in” – Provides “business agility” Sponsor open source projects – Provide funding, developer resources, infrastructure, management – Company benefits from the resulting product and the “brownie points” Examples – Android – Alliance for Open Media Mozilla, Microsoft, Google, Cisco, Intel, Amazon, Netflix

40. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 40 OSS has changed things… First step in a typical software process: look for open source components to fulfill requirements Branching out – Education – Filmmaking – Furniture

41. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 41 OSS Video https://www.youtube.com/watch?v=Tyd0FO0tko8

42. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 42 So… What is it good for? (strengths) What is it bad for? (weaknesses)

43. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 43 So… What is it good for? (strengths) – Software that benefits developers (oftentimes extends to the public at large) – Accessibility of open source software results in a huge user base, which also results in huge advances – Some of the greatest minds, motivated and working together to solve hard problems, in which they themselves are the users, can result in huge advances (novel features, better quality code) “Given enough eyeballs, all bugs are shallow.” – Eric Raymond

44. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 44 So… What is it good for? (strengths) – Software that benefits developers (oftentimes extends to the public at large) – Accessibility of open source software results in a huge user base, which also results in huge advances – Some of the greatest minds, motivated and working together to solve hard problems can result in huge advances (novel features, better quality code) What is it bad for? (weaknesses) – Proprietary software – Software with strict requirements and/or tight deadlines – Technical support/maintenance can be iffy – Developers are often not compensated financially

45. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 45 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

46. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 46 Extreme Programming (XP) More “extreme” reaction to Waterfall, other heavyweights… Kent Beck (also Ron Jeffries) – Software engineering consists of Listening, Testing, Coding, Designing – Based on Values of Simplicity, Communication, Feedback, Courage – Works by Simple practices, such as bringing/keeping the team together Just enough feedback to know where you are Just enough (and just in time) “heavier” activities More “programmer welfare” than other process models…

47. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 47 XP Practices and Principles (I) Whole team – Customer on site, part of the team Planning game – Once per iteration Small releases Customer tests Simple design – “Simple is best” – Refactoring encouraged Pair programming Test-driven development Design improvement – Refactor whenever, wherever possible

48. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 48 XP Practices and Principles (II) Continuous integration – Everyone works on the most recent version of the code Collective code ownership – Anyone can change any part of code – All team members work on all development activities Coding standards – Promotes shared understanding Metaphor – A “story” about the system Sustainable pace – 40-hour work weeks – short iterations Open space – Especially for pair programming

49. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 49 XP Process Steps Determine the desired features (stories) – Estimate time/cost (effort) per feature – Client can help determine order of development Story prioritization Stories further refined into development tasks Implement/deliver each task – Typically using… Test-driven development Pair programming Follow values and principles – (See previous slides)

50. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 50 XP Philosophies (I) Rapid, fine feedback – Frequent testing – On-site customer – Pair programming Continuous process – Continuous integration – Merciless refactoring – Small, frequent releases From Glenn Vanderburg, Delphi Consultants

51. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 51 XP Philosophies (II) Shared understanding – Planning game – Simple design – System metaphor – Collective code ownership – Coding conventions Developer welfare – Forty hour week From Glenn Vanderburg, Delphi Consultants

52. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 52 SimSE XP Demo

53. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 53 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

54. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 54 From XP to Agile Agile includes and evolved from – Extreme Programming – Scrum, Crystal, others The Agile Manifesto (2001) – “We have come to value…” – Individuals and interactions Over processes and tools – Working software Over comprehensive documentation – Customer collaboration Over contract negotiation – Responding to change Over following a plan

55. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 55 Some Agile Principles Welcome change in requirements – Even late in development – Harness change for competitive advantage Business people and developers work together daily throughout the project – Stand-up meetings Build projects around motivated individuals – Give them the environment and support they need

56. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 56 More Agile Principles Best method of conveying information during development is face-to-face conversation – Informal communication – Stand-up meetings Documentation is just a means to an end – Do only the necessary amount – Source code is the biggest part of the documentation

57. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 57 Some Agile Principles Continuous delivery: deliver working software frequently to satisfy the customer Figure credit: R. Souza, C. Chavez, and R. Bittencourt. Rapid releases and patch backouts: A software analytics approach. Software, IEEE, 32(2):89–96, Mar 2015.

58. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 58 Continuous delivery Tools – Integration repositories – Automated testing Methods – Timeboxing (time-based releases) – Sprints (feature-based releases) For each release, tradeoffs between – Schedule – Features – Quality Examples – Firefox/Chrome: 6-week release cycle – Google+: 36 hour release cycle – Facebook: 2 releases per day – Etsy.com: 36 releases per day (11 commits per release)

59. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 59 A closer look at one agile process (Scrum) https://www.youtube.com/watch?v=XU0llRltyFM

60. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 60 Some real life agile examples https://www.youtube.com/watch?v=szr0ezLyQHY https://www.youtube.com/watch?v=q1RqhRcPJZ0

61. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 61 So… What is it good for? (strengths) What is it bad for? (weaknesses)

62. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 62 So… What is it good for? (strengths) – Customer satisfaction – Adaptable to changing circumstances – Good for projects with unclear, changing requirements – Good for small teams What is it bad for? (weaknesses)

63. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 63 So… What is it good for? (strengths) – Customer satisfaction – Adaptable to changing circumstances – Good for projects with unclear, changing requirements – Good for small teams What is it bad for? (weaknesses) – Lack of documentation – Unstable requirements – Bad for projects with large teams – Bad for projects in which customer involvement is not possible

64. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 64 A Comparison of Life Cycle Models (Highlights) ModelStrengthsWeaknesses Build-and-FixFine for small programs that do not require much maintenance Totally unsatisfactorily for nontrivial programs WaterfallDisciplined approach Document driven Delivered product may not meet client’s needs Rapid Prototyping Ensures that delivered product meets client’s needs A need to build twice Cannot always be used IncrementalMaximizes early return on investment Requires open architecture May degenerate into build-and-fix SpiralIncorporates features of all the above models Developers have to be competent at risk-analysis RUPRisk-driven, incremental, lots of guidance Complicated, requires a process expert OSSRapid advances, high-quality software Developers do not benefit financially Agile/XPHigh customer satisfaction Adaptable to change Lack of documentation Requires small teams and customer involvement

65. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 65 Today’s lecture More Software Process Models – Spiral – Rational Unified Process (RUP) – Open Source Software (OSS) – Extreme Programming (XP) – Agile Quiz 6 study guide

66. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 66 Quiz 6 Readings: – Windows 10 article – Gamasutra article Discussion: – SimSE exercise (week 9) Lecture: – Know characteristics, strengths, and weaknesses of all process models covered through today

67. Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 67 Reminder Homework 3A due Tuesday 11/24, 11:55pm – No late assignments accepted except for extenuating circumstances as described in first lecture – Don’t forget your github username at the top of your document