waterfall model

Introduction The waterfall model is the most common model of all software development life cycle models. It is very simple to understand and use. In a waterfall model, each phase must be completed before the next phase can start. At the end of each phase, a review takes place to determine if the project is on the right path and whether or not the project should be continued. Here phases do not overlap with each other. Waterfall model is a sequential design process in which progress is seen as flowing steadily downwards through Conception, Initiation, Analysis, Design, Construction, Testing, Production/Implementation and Maintenance Phases. A Water Fall Model is easy to flow. It can be implemented for any size of project. Every stage has to be done separately at the right time so you cannot jump stages. Documentation is produced at every stage of a waterfall model allowing people to understand what has been done. Testing is done at every stage.

History The first formal description of the waterfall model is often cited as a 1970 article by Winston W. Royce. Royce did not use the term "waterfall" in this article. Royce presented this model as an example of a flawed, non-working model.

Characteristic
The project consists of sequential, non-overlapping phases, where a phase cannot begin until the previous phase is already completed.
- At the end of every phase, there is a gate where a decision is made to allow the project to move forward or not (Stage Gate)
- Changes are controlled. Major changes are only allowed if the CCB (Change Control Board) approves them.
- The product is only finished at the end of the last phase.
- Once the project is done, the product/service enters into a maintenance phase.

- Low overhead of the methodology compared to other methodologies (such as Agile).

Advantages
1. The water fall model is easy to implementation
2. For implementation of small systems water fall model is use full
3. The project requires the