1. 1 Chapter 7 Lifecycle Planning

2. 2 Lifecycles - Introduction A lifecycle model is a prescriptive model of what should happen between the first glimmer and the last breath of a (software) project It establishes the order in which a project specifies, prototypes, designs, implements, reviews, tests, and performs other activities Choosing a lifecycle for a project has the same influence over the success of a project than any other planning decision made The right choice can streamline your project and help to approach your goal in a sequence of successful steps

3. 3 continued … Source: Introducing Systems Analysis, Steve Skidmore, 1997

4. 4 continued … Strategic study Define possible IS contributions to the objectives of the enterprise Identification of candidate applications Feasibility study Examination and comparison of candidate applications Economic, technical, operational issues Output: feasibility report Recommends possible solution and comments whether detailed analysis should commence From this detailed systems project are initiated Physical systems analysis Start of a detailed systems investigation of the current system and the requirements of its successor Output: requirements analysis document

5. 5 continued … Logical systems definition Development of required system (models for data, processes and events) Output: requirements specification document Logical systems design Logically defining data structures (normalisation), and definition of detailed processes Output: logical design document Physical systems design Development of physical inputs and outputs, e.g., files, programs, databases Output: physical design Implementation Testing of programs and systems, development of support manuals and documentation, training courses, phasing in of the new system into the organisation Maintenance Implementation of amendments and omissions, new requirements, new hard/software

6. 6 Pure Waterfall Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

7. 7 continued … Basis for most models (starting point) Orderly sequence of steps Review at the end Does not proceed until goals are met Phases do not overlap Document driven Works well Stable product definition Well understood, complex problems All planning is done upfront Quality dominates cost and schedule Technically weak staff Disadvantages Poor visibility No tangible results until the end Sensitive to midstream changes Not flexibility Usually it is not possible to fully specify requirements at the start (before any design) In reality activities often overlap

8. 8 Salmon Waterfall Model Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

9. 9 Code-And-Fix Quite common Jump straight into coding If you don’t use any lifecycle model you are probably using code-and- fix Combined with short schedules it may lead to code-like-hell Advantage No overhead, may work for small projects System Specification (maybe) Code and Fix Release (maybe)

10. 10 Spiral Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

11. 11 Modified Waterfall - Sashimi Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

12. 12 Waterfall With Subprojects Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

13. 13 Waterfall With Risk Reduction Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

14. 14 Evolutionary Prototyping Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

15. 15 Staged Delivery Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

16. 16 Design-To-Schedule Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

17. 17 Evolutionary Delivery Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

18. 18 Design-To-Tools Source: Rapid Development - Taming Wilde Software Projects, McConnell, 1996

19. 19 Commercial Of-The-Shelf Software May not satisfy all your needs but Immediately available Often cheap, e.g., no costs for design, development Software product can be built around the functionality provided by a tool Free time for more important tasks Some functionality immediately available – good for customer feedback