Waterfall Model

This is the most common and classic of life cycle models, also referred to as a linear-sequential life cycle model. It is very simple to understand and use. In a waterfall model, each phase must be completed in its entirety before the next phase can begin. At the end of each phase, a review takes place to determine if the project is on the right path and whether or not to continue or discard the project.

 

Requirement (Diagram)

a. Design

b. Implementation & Unit Testing

c. Integration & System Testing

d. Operation

 

Advantages

a. Simple and easy to use.

b. Easy to manage due to the rigidity of the model – each phase has specific deliverables and a review process.

c. Phases are processed and completed one at a time.

d. Works well for smaller projects where requirements are very well understood.

 

Disadvantages

a. Adjusting scope during the life cycle can kill a project

b. Poor model for complex and object-oriented projects.

c. Poor model for long and ongoing projects.

d. Poor model where requirements are at a moderate to high risk of changing.