1. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Software Development Lifecycles (SDLC’s) 70-451 Management Information Systems Robert Monroe September 27, 2009

2. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Agenda Administrivia: exams, case analyses, homework #2 Roadmap for the upcoming module SDLC stages SDLC models

3. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Quiz 1.Did you enjoy your Eid holiday? 2.List three of the stages common to all software development lifecycles _____ ______ ______ 3.True or false: if your project has fallen behind schedule it is a good idea to just skip the testing phase

4. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Goals For Today By the end of today's class you should be able to explain: What a Systems Development Lifecycle model is What tasks are done in each of these stages, and by whom What questions each of the stages answers, and how The core principles behind the waterfall, spiral, and agile SDLC's The primary advantages and disadvantages of each of the SDLC's.

5. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems The Road Ahead: Acquiring IS Capabilities Week 1: –Systems Development Lifecycles –Requirements gathering and analysis Week 2: –Models for acquiring IS capabilities –IS projects: planning, project selection, risk management Week 3: –IS projects: development, testing, deployment, maintenance –Measuring IS performance Week 4: –Outsourcing

6. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Systems Development Lifecycles

7. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Systems Development Lifecycles (SDLC’s) There are many, many different approaches to selecting, planning, building, and deploying information systems These approaches/processes are commonly referred to as Systems Development Lifecycles (SDLC’s) Most SDLC’s consist of a series of stages in which common tasks are perfomed SDLC’s describe the order, tasks, deliverables, and interactions of the stages

8. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Most SDLC’s Share Common Stages Planning Analysis Design Development Testing Implementation Maintenance

9. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Planning Stage Basic questions to answer in this stage What is the purpose of this project Why are we going to undertake it How are we going to undertake it How long will it take and what resources will we need to complete it? What are the project goals? How will we know if and when we have met them? Who are the key stakeholders? What are our fundamental constraints? Output: Outline of a project plan Planning …

10. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Analysis and Design After project identification, approval and planning comes detailed analysis and design Analysis stage –Business analysis: detailed evaluation and specification of business requirements –Systems analysis: detailed evaluation of how the system will implement business requirements Design stage –User-centric design specifies how the system will work (user interface, funcional details, etc.) –Architecture specifies fundamental system design vocabulary and design rules Planning Analysis … √ Design

11. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Business Analysis The primary output of the business analysis stage is a set of detailed requirements that the information system must satisfy These requirements should: –Be expressed in language that business users understand –Specify what is needed, not how to implement it –Example: The system shall provide a report that lists cumulative sales for a user-specified time period, categorized by product line and region. –The user shall be able to interactively request such a report for any time period for which the system contains sales data –The report shall be shown to the user in no more than 30 seconds –The user shall be able to print a copy of the report

12. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Systems Analysis The Systems Analyst’s role is to figure out how to realize the business requirements for the system through technology The output of the systems analysis is a specification for how the system will function –Commonly known as a Functional Specification Document –Frequently provided from the user’s perspective (screens) –Also includes detailed “non-functional” requirements that specify other attributes of the system such as security, performance, scalability requirements, etc.

13. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Systems Architecture The Systems Architect is responsible for designing an information sytsem that implements the functional specification, especially the critical system attributes (security, scalability, etc.) The output of the Systems Architect is generally a document describing the system’s technical architecture

14. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Big Issues: Analysis And Design Managing scope Predicting time, effort, difficulty, and risk Managing change requests Confirming that the functional spec and system design satisfy the business requirements –Get all stakeholders involved early and often! Ensuring the technical architecture can support required system attributes (security, performance, availability, scalability, system volume)

15. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Development and Testing After design and architecture are sufficiently completed, it is time to build and test the system Development stage –Convert the requirements and design into a functioning information system (write software, build user interface, integrate 3 rd party components, write documentation, etc.) Testing stage –Confirm that the system meets its requirements Analysis and Design Development … √ Testing

16. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Development Tasks Coding Module development Systems integration (new system) Systems integration – external systems

17. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Big Issues: Development Managing complexity Communication and coordination across a group Dealing with change requests Dealing with discovered problems

18. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Types and Stages of IS Testing Unit test – does this software module work properly? Systems integration test – what happens when I integrate this system’s modules… –…with each other? –…with other systems? User Acceptance Testing –Does the system meet the requirements laid out originally? –Can people use the system to solve their business problems?

19. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Big Issues: Testing Nearly an infinite number of ways that a significant Information System can fail –But you have a very finite amount of time to test it Standard approach is to identify the most likely problems and make sure that they are not problems in this system –Identifying standard failure modes –Testing representative sets of test cases to cover these failure modes

20. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Testing Questions How do businesses make the tradeoff between time spent testing a system and trying to get it out there as soon as possible, bearing in mind the exponential increase in cost of fixing an error the later it is found? - Student question on wiki

21. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Implementation and Maintenance After Development and testing it is time to roll the system out to the organization Implementation stage –Install hardware and/or software –Update affected other systems (as needed) –Train users –Go Live! (cross fingers, hope for the best…) Maintenance –Fix bugs –Add new features and capabilities Development and Testing Implementation … √ Maintenance

22. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Major Implementation Issues Readiness of all affected people and systems –User training and acceptance –All dependent systems integration projects completed Staging the switch-over to the new system with minimal business disruption Four approaches to staging a system rollout

23. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems SDLC Questions How can a business fulfill all stages of the SDLC bu also become cost efficient? And which of these stages is the most important to apply fast if business faces a short term crisis? - student question posted to wiki Of the phases involved in SDLC, which do you think is the most improtant phase/phases and why do you think some companies choose to sometimes skip certain phases and what are the disadvantages of doing so? - student question posted to wiki

24. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Specific SDLC Models

25. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems SDLC Model: Waterfall Planning Analysis Design Development Testing Implementation Maintenance Traditional model Very linear Step A precedes Step B precedes Step C … Commonly used when system must (or can) be fully specified before development begins

26. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Waterfall Model Questions The textbook notes that the waterfall method has a notoriously poor record for delivering successful projects (~10% success rate!) –So why is it so frequently used? –… and why is it so difficult to use successfully? –Is it ever a good idea to use the waterfall method? If not, why? If so, when? –What does it mean to have a 10% success rate? How is that number determined? Is it reflective of reality?

27. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems SDLC Model: Spiral Planning Analysis Design Development Testing Implementation Maintenance (Part I) Start Deliver Part 1 Begin Part 2 Planning Analysis Design Development Testing Implement Deliver Part 2 Begin Part 3 Maintenance (Part 2) Planning Analysis Design Development Testing Implementation …

28. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems “Agile” SDLC Models Many different variations on ‘Agile’ SDLC’s –XP: eXtreme Programming –Rapid Prototyping / Rapid Application Development –‘Agile’ –… Key ideas common across agile methods –Small, frequent iterations with fast feedback loops –Embrace change –Customer-centric –Learn as you go, improve as you go –If something is not working, change it –Working system from very early on

29. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Agile Model Questions The textbook notes that the Agile methods seem to have a much better record for delivering successful projects (65% success rate quoted) –Do you trust the 65% number? Why or why not? –What are the advantages of Agile methods? –What are the drawbacks of Agile methods? –What makes them difficult to use successfully? –Under what circumstances might you want to use Agile methods? When might they not be appropriate?

30. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems There Are Many, Many SDLC’s Available Most work well in some situations and poorly in other situations –Choosing the correct SDLC for the correct situation is a skill developed primarily through experience Factors to consider when choosing an SDLC: –Size of organization undertaking the project –Complexity of the project –Routine vs. innovative –Personalities of the people involved Most successful SDLC’s include opportunities for measurement, feedback, and organizational learning

31. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems SDLC Selection Questions Based on what do firms choose which methodology to use? What are the relative costs of the different methodologies? - student question posted to wiki What factors should a company consider while selecting an SDLC model? - student question posted to wiki

32. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Wrap Up For Tuesday: Requirements Goals recap: By the end of today's class you should be able to explain: –What a Systems Development Lifecycle model is –What tasks are done in each of these stages, and by whom –What questions each of the stages answers, and how –The core principles behind the waterfall, spiral, and agile SDLC's –The primary advantages and disadvantages of each of the SDLC's.

33. Carnegie Mellon University ©2006 - 2009 Robert T. Monroe 70-451 Management Information Systems Exam #1 Results 123 total points possible High score: 117 Low score: 55 Median score: 99