Spiral model

Spiral mode is a step by step procedure to develop the new software. In order to overcome the drawback of water fall model we use spiral model. Spiral model is mainly used when there is a dependency in the modules or features or functionalities.

This model is also called as Iterative model or Incremental model.
In every cycle the same process is repeated so this model in called iterative model.
In every cycle we keep adding new module so the model is called incremental model.

Advantages:

• Requirement changes can be done after every cycle.
• Customers get an opportunity to see the software in every cycles.
• Testing is done in every cycle before going to next cycle.
• Spiral model is a controlled model. i,e When one module is completely stable then only we develop next module.

Drawbacks:

• Requirement collection and design phase are not tested
• Is not beneficial for smaller projects.
• Spiral may go infinitely.
• Documentation is more as it has intermediate phases.
• It is costly for smaller projects.

Applications:

When to use Spiral Methodology?

• Whenever there is a dependency in the modules
• When the customer gives the requirements in stages.
• When releases are required to be frequent
• For medium to high-risk projects
• When changes may require at any time
• When project is large