Spiral model - kubapeter/portfolio GitHub Wiki
The Spiral model is an [iterative process model]]. The model, introduced by Barry Boehm in 1986, outlines a basic [[process]] in which development teams can design and successfully implement a software system by revisiting [phases of the process after they have been previously completed.
Phases
A simplified version of the model has four phases:
- determine objectives
- identify and resolve risks
- develop and test
- plan the next iteration
Taken in order, the four phases represent one full iteration. Each subsequent iteration has the sequence of the four phases revisited, and each iteration results in a product prototype. Early iterations lead to product ideas and concepts, while later iterations lead to working software prototypes.
Iterations and prototypes
- The first iteration may be the creation of an illustrative prototype.
- Subsequent iterations could build on this illustrative prototype with either an incremental or an evolutionary prototype approach
Pros and cons
Pros:
- development team can review their product with the client to gather feedback and improve the product
- using a repetitive process to make further refinements is a clear advantage over the earlier linear models
Cons:
- estimating work can be more difficult
- lengthy iterations can introduce more uncertainty in estimate
- requires much analytical expertise to assess risks