The four phases of a typical waterfall model are

The waterfall model is to divide the software project into different phases, namely: analysis and definition phase, software design phase, coding and testing phase and operation and maintenance phase.

Advantages of the waterfall model:

1. Complete documentation of the phases, reducing communication costs.

2, each stage of the review before the next stage, quality assurance.

Disadvantages of the waterfall model:

1, does not adapt to changes in requirements, if the change before all stages must be adjusted.

2, each stage produces a large number of documents, management difficulties, heavy workload.

3, the user can not quickly see the software product, and then propose changes after use, the cost of change is very large.

Types of projects suitable for waterfall model: embedded systems, critical systems, large-scale software systems such systems user needs are very clear, often government-driven funding, personnel supporting adequate for waterfall model.