1. 1 The economies of ALL developed nations are dependent on software The economies of ALL developed nations are dependent on software More and more systems are software controlled More and more systems are software controlled Software engineering is concerned with theories, methods and tools for professional software development Software engineering is concerned with theories, methods and tools for professional software development Software engineering expenditure represents a significant fraction of GNP in all developed countries Software engineering expenditure represents a significant fraction of GNP in all developed countries Software engineering

2. 2 Software costs often dominate system costs. The costs of software on a PC are often greater than the hardware cost Software costs often dominate system costs. The costs of software on a PC are often greater than the hardware cost Software costs more to maintain than it does to develop. For systems with a long life, maintenance costs may be several times development costs Software costs more to maintain than it does to develop. For systems with a long life, maintenance costs may be several times development costs Software engineering is concerned with cost-effective software development Software engineering is concerned with cost-effective software development Software costs

3. 3 Software Engineering Most Challenging Two Goals Software MUST BE on time! Software MUST BE on time! One of the most challenging elements of quality complex software development and therefore of software engineering is to deliver it on schedule. One of the most challenging elements of quality complex software development and therefore of software engineering is to deliver it on schedule. Software MUST BE in budget! Software MUST BE in budget! The other most challenging aspect of quality complex software development and therefore of software engineering is to deliver the software within budget. The other most challenging aspect of quality complex software development and therefore of software engineering is to deliver the software within budget.

4. 4 A Process Framework SOFTWARE PROCESS Process framework Umbrella Activities Framework activities # m (n  m of them) work tasks work products QA checkpoints milestones & deliverables

5. 5 Framework Activities (five) Communication Communication Requirements gathering Requirements gathering Planning Planning Schedule & risks Schedule & risks Modeling Modeling Analysis of requirements Analysis of requirements Design Design Construction Construction Code generation Code generation Testing Testing Deployment (S/W delivery) Deployment (S/W delivery)

6. 6 The Process Model: Adaptability the framework activities will always be applied on every project... BUT the framework activities will always be applied on every project... BUT the tasks (and degree of rigor) for each activity will vary based on: the tasks (and degree of rigor) for each activity will vary based on: the type of project the type of project characteristics of the project characteristics of the project common sense judgment; concurrence of the project team common sense judgment; concurrence of the project team

7. 7 Umbrella Activities Software project management (tracking & control) Risk management (includes quality of the product) Software quality assurance Formal technical reviews (remove errors) Measurement (assist in delivering the right S/W) Software configuration management Reusability management Work product preparation and production

8. California State University, Fall 2008, Part I 8 Assessment and Improvement as they relate to S/W Process

9. California State University, Fall 2008, Part I 9 Prescriptive Models Prescriptive process models advocate an orderly approach to software engineering Prescriptive process models advocate an orderly approach to software engineering That leads to a few questions … If prescriptive process models strive for structure and order, are they inappropriate for a software world that thrives on change? If prescriptive process models strive for structure and order, are they inappropriate for a software world that thrives on change? Yet, if we reject traditional process models (and the order they imply) and replace them with something less structured, do we make it impossible to achieve coordination and coherence in software work? Yet, if we reject traditional process models (and the order they imply) and replace them with something less structured, do we make it impossible to achieve coordination and coherence in software work?

10. California State University, Fall 2008, Part I 10 The Waterfall Model: First Version Communication Planning Modeling Construction Deployment analysis design code test project initiation requirement gathering estimating scheduling tracking delivery support feedback Also called the classic life cycle is the oldest paradigm for software engineering. Also called the classic life cycle is the oldest paradigm for software engineering. Cons: Cons: real projects rarely follow a sequential flow real projects rarely follow a sequential flow requirements are not initially completely explicit requirements are not initially completely explicit customer has to wait until deployment takes place customer has to wait until deployment takes place if a problem occurs (most likely) is detected only at the end if a problem occurs (most likely) is detected only at the end Pros: Pros: there is a level of feedback implicit in the model there is a level of feedback implicit in the model a linear model is easy to understand a linear model is easy to understand provides a nice simple model to work with provides a nice simple model to work with

11. 11 The Waterfall Model: Another Version There are many representations of the waterfall model with several stages (more There are many representations of the waterfall model with several stages (more than 5) but for our practical purposes we will use 5 stages. Notice that ‘coding” occurs during the implementation stage. Requirements Definition System and Software Design Implementation and unit testing Integration and system testing Operation and maintenance

12. 12 Evolutionary Models: The Spiral

13. 13 UP Phases

14. California State University, Fall 2008, Part I 14 Agile Development

15. 15 The Manifesto for Agile Software Development “We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value: Individuals and interactions over processes and toolsIndividuals and interactions over processes and tools Working software over comprehensive documentationWorking software over comprehensive documentation Customer collaboration over contract negotiationCustomer collaboration over contract negotiation Responding to change over following a planResponding to change over following a plan That is, while there is value in the items on the right, we value the items on the left more.” Kent Beck et al (16 more)

16. 16 What is “Agility”? Effective (rapid and adaptive) response to change Effective (rapid and adaptive) response to change Effective communication among all stakeholders Effective communication among all stakeholders Drawing the customer onto the team Drawing the customer onto the team Organizing a team so that it is in control of the work performed Organizing a team so that it is in control of the work performed Yielding … Rapid, incremental delivery of software Rapid, incremental delivery of software

17. 17 An Agile Process Is driven by customer descriptions of what is required (scenarios) Is driven by customer descriptions of what is required (scenarios) Recognizes that plans are short-lived Recognizes that plans are short-lived Develops software iteratively with a heavy emphasis on construction activities Develops software iteratively with a heavy emphasis on construction activities Delivers multiple ‘software increments’ Delivers multiple ‘software increments’ Adapts as changes occur Adapts as changes occur

18. 18 Extreme Programming (XP) The most widely used agile process, originally proposed by Kent Beck The most widely used agile process, originally proposed by Kent Beck XP Planning XP Planning Begins with the creation of “user stories” Begins with the creation of “user stories” Agile team assesses each story and assigns a cost Agile team assesses each story and assigns a cost Stories are grouped to for a deliverable increment Stories are grouped to for a deliverable increment A commitment is made on delivery date A commitment is made on delivery date After the first increment “project velocity” is used to help define subsequent delivery dates for other increments After the first increment “project velocity” is used to help define subsequent delivery dates for other increments

19. 19 Extreme Programming (XP) XP Design XP Design Follows the KIS (keep-it-simple) principle Follows the KIS (keep-it-simple) principle Encourage the use of CRC (class responsibility collaboration) cards Encourage the use of CRC (class responsibility collaboration) cards For difficult design problems, suggests the creation of “spike solutions”—a design prototype For difficult design problems, suggests the creation of “spike solutions”—a design prototype Encourages “refactoring”—an iterative refinement of the internal program design Encourages “refactoring”—an iterative refinement of the internal program design XP Coding XP Coding Recommends the construction of a unit test for a store before coding commences Recommends the construction of a unit test for a store before coding commences Encourages “pair programming” Encourages “pair programming” XP Testing XP Testing All unit tests are executed daily All unit tests are executed daily “Acceptance tests” are defined by the customer and executed to assess customer visible functionality “Acceptance tests” are defined by the customer and executed to assess customer visible functionality

20. 20 Extreme Programming (XP)

21. 21 Adaptive Software Development (ASD) Originally proposed by Jim Highsmith Originally proposed by Jim Highsmith ASD — distinguishing features ASD — distinguishing features Mission-driven planning Mission-driven planning Component-based focus Component-based focus Uses “time-boxing” Uses “time-boxing” Explicit consideration of risks Explicit consideration of risks Emphasizes collaboration for requirements gathering Emphasizes collaboration for requirements gathering Emphasizes “learning” throughout the process Emphasizes “learning” throughout the process

22. 22 Adaptive Software Development

23. 23 Dynamic Systems Development Method (DSDM) Promoted by the DSDM Consortium (www.dsdm.org) Promoted by the DSDM Consortium (www.dsdm.org)www.dsdm.org DSDM—distinguishing features DSDM—distinguishing features Similar in most respects to XP and/or ASD Similar in most respects to XP and/or ASD Nine guiding principles Nine guiding principles Active user involvement is imperative. Active user involvement is imperative. DSDM teams must be empowered to make decisions. DSDM teams must be empowered to make decisions. The focus is on frequent delivery of products. The focus is on frequent delivery of products. Fitness for business purpose is the essential criterion for acceptance of deliverables. Fitness for business purpose is the essential criterion for acceptance of deliverables. Iterative and incremental development is necessary to converge on an accurate business solution. Iterative and incremental development is necessary to converge on an accurate business solution. All changes during development are reversible. All changes during development are reversible. Requirements are baselined at a high level Requirements are baselined at a high level Testing is integrated throughout the life-cycle. Testing is integrated throughout the life-cycle.

24. 24 Dynamic Systems Development Method DSDM Life Cycle (with permission of the DSDM consortium)

25. 25 Scrum Originally proposed by Schwaber and Beedle Originally proposed by Schwaber and Beedle Scrum—distinguishing features Scrum—distinguishing features Development work is partitioned into “packets” Development work is partitioned into “packets” Testing and documentation are on-going as the product is constructed Testing and documentation are on-going as the product is constructed Work occurs in “sprints” and is derived from a “backlog” of existing requirements Work occurs in “sprints” and is derived from a “backlog” of existing requirements Meetings are very short and sometimes conducted without chairs Meetings are very short and sometimes conducted without chairs “demos” are delivered to the customer with the time-box allocated “demos” are delivered to the customer with the time-box allocated

26. 26Scrum

27. 27 Crystal Proposed by Cockburn and Highsmith Proposed by Cockburn and Highsmith Crystal—distinguishing features Crystal—distinguishing features Actually a family of process models that allow “maneuverability” based on problem characteristics Actually a family of process models that allow “maneuverability” based on problem characteristics Face-to-face communication is emphasized Face-to-face communication is emphasized Suggests the use of “reflection workshops” to review the work habits of the team Suggests the use of “reflection workshops” to review the work habits of the team

28. 28 Feature Driven Development Originally proposed by Peter Coad et al Originally proposed by Peter Coad et al FDD—distinguishing features FDD—distinguishing features Emphasis is on defining “features” Emphasis is on defining “features” a feature “is a client-valued function that can be implemented in two weeks or less.” a feature “is a client-valued function that can be implemented in two weeks or less.” Uses a feature template Uses a feature template the a(n) the a(n) A features list is created and “plan by feature” is conducted A features list is created and “plan by feature” is conducted Design and construction merge in FDD Design and construction merge in FDD

29. 29 Feature Driven Development Reprinted with permission of Peter Coad

30. 30 Agile Modeling Originally proposed by Scott Ambler Originally proposed by Scott Ambler Suggests a set of agile modeling principles Suggests a set of agile modeling principles Model with a purpose Model with a purpose Use multiple models Use multiple models Travel light Travel light Content is more important than representation Content is more important than representation Know the models and the tools you use to create them Know the models and the tools you use to create them Adapt locally Adapt locally

31. 31 What is “Agility”? Effective (rapid and adaptive) response to change Effective (rapid and adaptive) response to change Effective communication among all stakeholders Effective communication among all stakeholders Drawing the customer onto the team Drawing the customer onto the team Organizing a team so that it is in control of the work performed Organizing a team so that it is in control of the work performed Yielding … Rapid, incremental delivery of software Rapid, incremental delivery of software