Waterfall Model SDLC

So what is Waterfall Model ?

Waterfall model is an example of Sequential model. In this model, the software development activity is divided into different phases and each phase consists of series of tasks and has different objectives.
Waterfall model is the pioneer of the SDLC processes. In fact it was the first model which was widely used in the software industry. It is divided into phases and output of one phase becomes input of the next phase. It is mandatory for a phase to be completed before the next phase starts. In short, there is no overlapping in Waterfall model
In waterfall, development of one phase starts only when the previous phase is complete. Because of this nature, each phase of waterfall model is quite precise well defined. Since the phase’s falls from higher level to lower level, like a water fall, It’s named as waterfall model.

STRENGTHS:

1. Easy to understand and easy to use.
2. Provides a reference to inexperienced staff.
3. Milestones are well-understood by the team.
4. Provides requirements stability.
5. Facilitates strong management control(i.e plan,staff,track).
6. Works well when quality is more important than cost or schedule.

WEAKNESSES:

1. All requirements are to be known upfront.
2. Deliverables are created for each phase,and considered to be frozen – inhibits flexibility.
3. Can give a false impression of progress.
4. Integration is one big-bang at the end.
5. Little opportunity for customer to preview the system.