SDLC Spiral Model: Phases in Prototype Model, Advantages and Disadvantages of Spiral Model

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SDLC Spiral Model Topics

What is Spiral Model?

  • The spiral model was proposed by BOHEM in 1985. it is called spiral model because of its Spiral shape. Spiral model is one of the most important Software Development Life Cycle models, which provides support for risk handling. The spiral model is used for large projects requiring frequent enhancement. It is not used in small projects and this model is very expensive.
  • Spiral model is also called Meta-Model as it includes both waterfall Model and prototype model i.e.. It is a combination of both waterfall model and prototype model.

Phases in Prototype Model

The spiral model has four phases:

  • Planning
  • Risk analysis
  • Engineering
  • Evaluation

Below diagram shows the different phases of the Spiral Model:

Project Evaluation


All requirement is collected in the planning phase. That is, these requirements are studied and analyzed in order to estimate the necessary budget processing time etc. in the development of the software. In this stage, we discuss about what we need? what we want to achieve? or what is its goal?

Risk Analysis

In this phase of the spiral model, all possible risk in software development is identified. And if any risk is found, its solution is taken out.


The whole process of software development comes in this phase. Coding and testing are done in engineering phase.


When the software is ready, the customer evaluates it and the user gives his feedback and approval on the developed software.

Advantages of Spiral Model

  • Any development is very fast.
  • Evolution of any risk is appropriate and all stages of development are controlled.
  • More features are added in a symmetric way.
  • Large projects and software are created and handled in a strategic way.
  • Software is made quickly; user feedback and any changes can be implemented rapidly.
  • Spiral model is quite flexible in software development.

Disadvantage of Spiral Model

  • Spiral Model is not suitable for small projects as it is expensive.
  • Intermediate phase requires a lot of documentation.
  • As the number of phases is unknown at the start of the project, so time estimation is very difficult.
  • This model has a risk analysis as an important phase, so experts are needed.


Spiral model is one of the most important Software Development Life Cycle models, Spiral model is known to be quite flexible in software development as it helps to define objectives, analyze risk and plan for each stage of the project.


Q. 1. Spiral model is also called as________

(1) Waterfall model

(2) Prototype model

(3) Meta- model

(4) V-shape model

Answer: (3) Meta- Model

Q. 2. In which phase coding and testing is done in the spiral model?

(1) Planning phase

(2) Engineering phase

(3) Risk analysis phase

(4) Evolution phase

Answer: (2) Engineering phase

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