The Spiral Model (SW process)

Introduced by Barry Boehm in 1986, the Spiral Model was designed to address the shortcomings of the traditional Waterfall model, particularly for large, complex projects. Each loop of the spiral represents a phase of the Software process. Unlike other models, it doesn’t start with a full set of requirements. Instead, the initial spiral might focus on developing a proof-of-concept to test feasibility. Each subsequent loop builds upon the last, moving from a conceptual level to a fully engineered product. The four key activities in each cycle are: 1) Determine objectives, alternatives, and constraints for the iteration. 2) Evaluate alternatives; identify and resolve risks. This is the most critical part, involving activities like prototyping, simulation, and benchmarking to mitigate high-risk elements. 3) Develop and verify the next-level product. This involves the actual coding, integration, and testing, similar to a mini-waterfall process for that iteration’s deliverable. 4) Plan the next iteration. The project is reviewed, and plans are drawn up for the next spiral. This model allows for the incremental release of the product and refinement of requirements throughout the development lifecycle, making it highly flexible and suitable for projects where risk management is paramount.