425857380-Spiral-Modeljssjjsgjsjjsf.pptx

knowledge of spiral model

1. Spiral Model

2. Contents History What Is Spiral Model? Phases Graphical Representation Advantages and Disadvantages Comparison Applications Example Conclusion

3. History Barry Boehm first described the Spiral model in his 1986 paper, a Spiral Model of Software Development and Enhancement. In 1988 Boehm published a similar paper to a wider audience. This paper introduced a diagram that has been reproduced in several subsequent publications discussing the spiral model. Boehm’s early papers use the term "Process Model" to refer to the Spiral Model. The Spiral Model has characteristics of Incremental, Waterfall, Prototyping, and other approaches. However, the Spiral Model’s ability to analyze risk is superior to the models.

4. What is Spiral Model? The spiral model, also known as the spiral lifecycle model, is a systems development method (SDM) used in information technology (IT). This model of development combines the features of the prototyping model and the waterfall model. The spiral model is intended for large, expensive, and complicated projects. The spiral model is similar to the incremental model, with more emphasis placed on risk analysis. The Spiral Model has Four Phases: i . Planning ii. Risk analysis iii. Engineering iv. Evolution Software Project repeatedly passes through these four phases in iterations (known as spirals) The baseline spiral, starting in the planning phase, requirement are gathered and risk is assessed. Each subsequent spiral builds on the baseline spirals.

5. Phases of Spiral Model Planning : Purpose : Requirement Analysis Activities Performed: - Requirements are studied and gathered. - Feasibility study. - Reviews and walkthroughs to streamline the requirements. Deliverables / Output: - Requirements understanding document. - Finalized list of requirements. Risk Analysis: Purpose : Prototype Activities Performed: - Requirements are studied and brain storming sessions are done to identify the potential risks. - Once the risks are identified , risk mitigation strategy is planned and finalized. Deliverables / Output: - Document which highlights all the risks and its mitigation plans.

6. Phases of Spiral Model Engineering And Execution: Purpose : Development & Testing Activities Performed: - Actual development and testing if the software takes place in this phase. Deliverables / Output: - Code. - Test cases and test results. - Test summary report and defect report. Evaluation : Purpose : Customer Evaluation Activities Performed: - Customers evaluate the software and provide their feedback and approval Deliverables / Output: - Features implemented document .

7. When to use spiral model? When costs and risk evaluation is important. For medium to high-risk projects. Users are unsure of their needs. Requirements are complex. Significant changes are expected.

8. Graphical representation

9. Graphical representation

10. Advantages & Disadvantages Advantages High amount of risk analysis hence, avoidance of Risk is enhanced. Good for large and mission-critical projects. Strong approval and documentation control. Additional Functionality can be added at a later date. Software is produced early in the software life cycle. Project estimates in terms of schedule, cost etc become more and more realistic as the project moves forward and loops in spiral get completed.   It is suitable for high risk projects, where business needs may be unstable. A highly customized product can be developed using this. Disadvantages Can be a costly model to use. Risk analysis requires highly specific expertise. Project’s success is highly dependent on the risk analysis phase. Doesn’t work well for smaller projects. It is not suitable for low risk projects. May be hard to define objective, verifiable milestones. Spiral may continue indefinitely.

11. Comparison Graphs

12. Applications The spiral model is used most often in large projects (by companies such as IBM, Microsoft, Patni Computer Systems and Tata Consultancy Services ) and needs constant review to stay on target. For smaller projects, the concept of agile software development is becoming a viable alternative. The US military has adopted the spiral model for its Future Combat Systems program.

13. Example An example of the spiral model is the evolution of Microsoft Windows Operating system from Windows 3.1 to windows 2003. We may refer to Microsoft windows 3.1 Operating System as the first iteration in the spiral approach. The product was released and evaluated by the customers, which include the market large. After getting the feedback from customers about the windows 3.1, Microsoft planned to develop a new version of windows operating system. Windows’95 was released with the enhancement and graphical flexibility. Similarly, other versions of windows operating system were released

14. Conclusion Each spiral can be termed as a loop and each loop is a separate developmentprocess in a spiral model. The four activities (Planning, Risk analysis, engineering and evaluation) form the intermediary phases of a spiral model and is repeated again for each loop. This model is very good to use for larger projects where you can develop and deliver smaller prototypes and can enhance it to make the larger software