What is Spiral Model?
We use Spiral model whenever there is a dependency between modules. In Spiral model, the software product is developed in small modules. Spiral model is used to develop a software that consists referential integrity between modules. In spiral model, software is developed in a series of incremental releases. The spiral model is divided into a number of framework, activities or task. Each spiral consists of a deliverable product. Feedback of each spiral is incorporated in the text spiral. The client can start using the system after every spiral.
Steps followed in spiral model –
- Requirement collection
Requirement Collection: – Requirement collection is the first step of spiral modal. In this step requirement collected from the client side as per module before designing. Business analyst collected requirements in the form of CRS (customer requirement specification) and Convert it into SRS (Software requirement specification).
Designing: – In designing step designs are prepared by the senior developer on the basis of requirement. Designs are will be changed as per requirements.
Development: – In this step, development starts as per designs or requirements. Development is done by developers module by module. After developers develop one feature/module of the product, then only a developers can go on to develop the next module of the product.
Testing: – Testing performed for new modules/ features first. After that newly added feature or module dependency will be tested with other feature or modules.
When do we add new feature/ Module?
Firstly requirement collection takes place then design process done as per new requirement after that development steps involved, after completion of development, testing performed by testers, In this process test engineer firstly test new added feature/ module then test the dependency at old modules/ features to check the overall impact of the new feature.
Two types of changes involved in this modal: –
- Major changes: – When the changes made in the half part of the old features the changes known as major changes. In this change testing performed, firstly test half part in which changes made, after that test the remaining half part, then test the overall impact if there are other features involved.
- Minor changes: – When we add the new features, then bug fixing or changes we make in the feature is known as minor changes. After these changes first test the newly added feature, then test feature in which changes made after that bug fixing and at last test the dependency of all old features.
Advantages of Spiral Model: –
- This model is Useful for large projects.
- It is a flexible model since it is allow requirement changes.
- Customer can see the product in early stages of development.
- Early availability of the usable system.
Disadvantages of Spiral Model: –
- It is a time consuming model.
- Testing is a small phase after coding.
- Development is module by module.
- Developers are involved in testing.
- Whenever customer is new to the software.
- Whenever requirements are not cleared.
- Use for large and complex projects.
Whenever there is a dependency in building the different modules of the software, then we use Spiral Model.