Spiral Model Is Proposed to

Spiral Model is proposed to deal with risk. In this model, the total system will not be defined at the start. The developers just define the uppermost priority features and implement them. Then, they get the feedback from the users or customers. The developers will use these feedbacks to define more features and implement them in smaller groups. (What is the 'Spiral Model) Spiral model is an iterative model and is an improvement over waterfall model.

Waterfall model assumes that in a system everything can be defined perfectly; once everything is implemented, there is no need for feedback, which is similar to waterfall in that water does not go up. but, reality does not match with waterfall model. User-friendly designers frequently use spiral model to maintain the interests of the user by providing minimum features at the beginning and then based on user's creativity and feedback improves the system. (Spiral learning) The Spiral Model was offered by Boehm in 1985 and is focused on risk management.

To describe the relations between software development phases, life cycle models are used. One of the best life cycle models is the Spiral model. A few advantages of the Spiral model are: "postpones low risk software components; includes prototyping as a risk reduction strategy; gives an early focus to reusable software; accommodates life-cycle evolution and incorporates software quality objectives into the product." (Software Life Cycle Models) to develop software and system requirements, the Spiral model employs Win-Win Theory.

The Win-Win negotiation tool is a Unix workstation-based groupware support system that permits stakeholders to go into winning conditions, investigate their interactions, and negotiate joint agreements on the particulars of the new project being signed up. (WinWin Spiral Model) The spiral model merges the iterative character of prototyping with the organized and methodical features of the waterfall model, therein offering the possibility for quick development of incremental models of the software.

In this model, the software is developed in a sequence of incremental releases with the initial stages being either paper models or prototypes. Later iterations become more and more full versions of the product. This model may have 6 steps: Customer communication; Planning; Risk analysis; Engineering; Construction and release and evaluation of the Customer. (the Spiral Model) References Spiral learning" Retrieved at http://headrush.typepad.com/creating_passionate_users/2005/02/spiral_learning.html. Accessed on 16 February 2005 Software.