Information Technology Reference
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Risk
Analysis
Prototype
Risk
Analysis
Prototype
Risk
Analysis
Prototype
Test
Planning
System
Concept
Development
Plan
Software
Requirements
Requirement
Validation
Product
Design
Design
Validation
Detailed
Design
Delivery
Code
Integrate
Te s t
FIGURE 2.3
Spiral model.
2. A preliminary design is created for the new system.
3. A first prototype of the new system is constructed from the preliminary design.
This is usually a scaled-down system, and it represents an approximation of
the characteristics of the final product.
4. A second prototype is evolved by a fourfold procedure: 1) evaluating the first
prototype in terms of its strengths, weaknesses, and risks; 2) defining the
requirements of the second prototype; 3) planning and designing the second
prototype; and 4) constructing and testing the second prototype.
5. At the customer's option, the entire project can be aborted if the risk is deemed
too great. Risk factors might involve development cost overruns, operating-
cost miscalculation, or any other factor that could, in the customer's judgment,
result in a less-than-satisfactory final product.
6. The existing prototype is evaluated in the same manner as was the previous
prototype, and if necessary, another prototype is developed from it according
to the fourfold procedure outlined.
7. The preceding steps are iterated until the customer is satisfied that the refined
prototype represents the final product desired.
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