Software Development Models (Waterfall model)

1)Waterfall model:

 

       When to Use:

• Requirements are very well known, clear and fixed.
• Product definition is stable.
• Technology is understood.
• There are no ambiguous requirements
• Ample resources with required expertise are available freely
• The project is short.

       Advantages:

• Simple and easy to understand and use.
• Easy to manage due to the rigidity of the model – each phase has specific deliverable and a review process.
• Phases are processed and completed one at a time.
• Works well for smaller projects where requirements are very well understood.

       Disadvantages

• Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.
• No working software is produced until late during the life cycle.
• High amounts of risk and uncertainty.
• Not a good model for complex and object-oriented projects.
• Poor model for long and ongoing projects.
• Not suitable for the projects where requirements are at a moderate to high risk of changing.