The combination of iterative development with the systematic, controlled aspects of the waterfall model is spiral model. Waterfall model with high emphasis on risk analysis. It has four phases and each phase is called spiral.
The phases of spiral model are :
- Identification : This phase starts with gathering the requirements for the development of the software.
- Design : This phase starts with designing the basic model of the software.
- Construct or build : This refers to the construction of the actual software at every spiral.
- Evaluation and risk analysis : This includes the identification and the management of the risks that occur.
Spiral Model is very widely used in the software industry as it is in sync with the natural development process of any product. The advantage of spiral life cycle model is that it allows for elements of the product to be added in when they become available or known.