Waterfall model is a sequential process in the process of software development. In this process, the progress is seen in steadily downward direction.
There are five phases of a waterfall model. They are :
- Requirements : all the requirements of the software are documented.
- Design : This results in software architecture.
- Implementation : The software is implemented.
- Verification : Verification of bugs is done.
- Maintenance : This includes the maintenance of the software.
This model originates in the manufacturing and construction industries. Clients may not know exactly what their requirements are. So they keep changing their requirements. Thus, it becomes a bit difficult for the designer to analyse the requirements and build a software. Designers may not be aware of the problems that are yet to occur in the future because of that software. Due to these problems the waterfall model is further modified as Sashimi. It is a modified waterfall model with overlapping phases.