Water Fall Model

This is named so because of it’s diagrammatic representation resembles a cascade of waterfalls. The waterfall approach does not define the process to go back to the previous phase to handle changes in requirement. The waterfall approach is the earliest approach and most widely known that was used for software development.

 

Usage:

It’s utility is when Projects does not  focus on changing the requirements, for example, projects initiated from a request for proposals (RFPs), the customer has a very clear documented requirements. It is used when Project is short, Requirement is clear and environment is stable.

 

Merits:

• Helps to plan and schedule the project.
• Verification at each stage ensures early detection of errors/misunderstanding.
• Before the next phase of development, each phase must be completed
• They should perform quality assurance test (Verification and Validation) before completing each stage

 

Demerits:

• Assumes that the requirements of a system can be frozen.
• A little flexibility and adjusting scope is difficult and expensive.
• It is not desirable for complex project where requirement changes frequently
• Testing period comes quite late in the developmental process