Spiral Model Definition, Spiral Model Application, Advantage, Disadvantage

SPIRAL MODEL

Definition -

The spiral model is one of the most essential Software Development Life Cycle models, which provides support for Risk Handling. In its diagrammatic representation, it looks like a spiral with many loops. The exact number of loops of the spiral is unknown and can vary from project to project. Each loop of the spiral is called a Phase of the software development process. The exact number of phases needed to develop the product can be varied by the project manager depending upon the project risks. As the project manager dynamically determines the number of phases, so the project manager has an important role to develop a product using the spiral model.

At any point, the Radius of the spiral represents the project's expenses(cost) so far, and the angular dimension represents the progress made so far in the current phase.

(SPIRAL MODEL)

Based on the customer evaluation, the software development process enters the next iteration and subsequently follows the linear approach to implement the feedback suggested by the customer. The process of iterations along the spiral continues throughout the life of the software.

Spiral Model Application -

• When there is a budget constraint and risk evaluation is important.
• For medium to high-risk projects.
• Long-term project commitment because of potential changes to economic priorities as the requirements change with time.
• Customer is not sure of their requirements which is usually the case.
• Requirements are complex and need evaluation to get clarity.
• The new product line which should be released in phases to get enough customer feedback.
• Significant changes are expected in the product during the development cycle.

ADVANTAGES -

• Changing requirements can be accommodated.
• Allows extensive use of prototypes.
• Requirements can be captured more accurately.
• Users see the system early.
• Development can be divided into smaller parts and the risky parts can be developed earlier which helps in better risk management.

DISADVANTAGES -

• The end of the project may not be known early.
• Not suitable for small or low-risk projects and could be expensive for small projects.
• The process is complex.
• The Spiral may go on indefinitely.
• A large number of intermediate stages require excessive documentation.