What is Spiral Model

What is Spiral Model ?

spiral model :

• The Spiral Model was first invented  by Berry Bohem in 1986.
• The Spiral Model is more emphasis placed on risk Analysis .
• Each phase of Spiral Model begin with a Design goal and ends with the Client Reviewing the progress .
• The Spiral Model has Four phases -  i) Planning (Design)                                                            ii) Risk Analysis

                                                                  iii) Engineering

                                                                  iv) Evaluation

• A software project rapidly passes through these phases in iteration
• The development Team in Spiral model start with a small set of requirement and goes through each development phase for those set of requirement . 

  When to use Spiral Model : 

• When the project is large
• Where the Software needs Contiguous risk evaluation 
• Requirement are bit complected and require  contiguous classification 
• Software Requirement sufficient changes

Phases : 

• Planning (Design)
•  Risk Analysis
•  Engineering
• Evaluation

1) Planning : This phase start with knowing the business requirement in the line of spiral. this is the  1st phase of spiral model. In this phase we planned something basis of software requirement but that client has not satisfy.

2) Risk Analysis : In this phase we start the project with planned but the client need to change that is a risk . so  in this phase we handle that type of risk and other risk like the code properly run etc.

3)Development And Testing : In this phase  as per client requirement we configure our project but that is not fixed because the in this model client upgrade their requirement and with basis the requirement we design and phase again Risk  then we develop our code.

4) Evaluation : This is Client  phase the Client visit lots of time and see the project until they are develop a client requirement fulfill project.

Advantage : 

• development fast 
• large project easily handle
• Risk Evaluation proper way
• More and more feature added systematically
• take every  customer feedback and design faster

 Disadvantage : 

• Risk Analysis is the Impotent Phase  So require expert people
• Spiral may go infinite loop
• It is costly for smaller project
• It is  not suitable for small project