Determine in detail about Waterfall model

Waterfall model provides a sequential and systematic approach to software development and is better than build and fix approach. However, in this model, complete requirements must be available at the time of commencement of the project though in actual practice, requirements keep on originating during different phases. Water fall model can accommodate new requirements only in maintenance phase. Furthermore it doesn't incorporate any kind of risk assessment. In waterfall model, a working model of software isn't available. Therefore, there is no methods to judge the problems of software in between different phases.

A slight modification of waterfall model is a model with feedback. Once software is developed and is operational, then feedback to various phases maybe given.

Figure below depicts the Water Fall Model with feedback.