Waterfall and spiral model

SDLC

1. Waterfall and Spiral Model Project Management Reported by: Honey Mae Llanto

2. Waterfall Model It is a model which was developed for software development; that is to create software. This was first put forth by Winston Royce in 1970 in one of his articles.

3. Waterfall Model Phases Analysis Design Technical Design/ Detailed Design Implementation and Coding Testing Integration Acceptance Test Management and Maintenance

4. Benefits of Waterfall Model The project requires the fulfillment of one phase, before proceeding to the next. Provides structure to inexperienced staff Works well when quality is more important than cost or schedule

5. Shortcomings of Waterfall Model Many software projects are dependent upon external factors. A huge amount of time is also wasted. Little opportunity for customer to preview the system. All requirements must be known upfront

6. When to use the Waterfall Model Requirements are very well known Product definition is stable Technology is understood New version of an existing product

7. Spiral Model This model is preferred for large, expensive and complicated projects. It combines the features of Prototyping and Waterfall models.

8. Spiral Model Phases Envisioning Phase Planning Phase Developing Phase Stabilizing Phase Deploying Phase

9. Spiral Model Strengths Early and frequent feedback from users Users see the system early because of rapid prototyping tools Provides early indication of risks. Users can be closely tied to all lifecycle steps

10. Spiral Model Weaknesses Time spent for evaluating risks too large The model is complex Risk assessment expertise is required May be hard to define objective, verifiable milestones that indicate readiness to proceed through the next iteration

11. When to use Spiral Model When creation of a prototype is appropriate Requirements are complex Significant changes are expected Users are unsure of their needs

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