analysis phase. In the other hand, the Spiral Model presents the
phase of analysis, besides the requirements gathering, in the
analysis of alternatives established through the customer's needs.
The Spiral Model shows an analysis more focused in the risk of
the project where its execution could be interrupted in case of the
non-feasibility are greater than the feasibilities. The Waterfall
Model just presents the revision of the requirements.
Differences in the need for human involvement: For both
models the human involvement is fundamental in the analysis
criteria.
Differences in the development procedure: The Spiral Model
presents the analysis based on alternative solutions and feasibility
study. The project could be cancelled depending on the appraised
risks. The Waterfall Model presents a flow of requirements
revision, addressing in a looping between the phases, until all the
requirements have been reviewed. The continuity of the project is
not approached in the model.
Differences in scope of issues: The Waterfall Model presents the
analysis phase based on requirements while in the Spiral Model
analysis based on requirements, risks and alternative solutions.
Comparison between Design Phase
Differences in the inter-component dependency: There are no
differences between dependences assuming that the inputs
Detailed Design of the Waterfall Model and Procedure Detailed of
the Spiral Model have the same necessary inputs for the
construction of the programs.
Differences in the need for human involvement: For both
models the human involvement is fundamental in the
implementation phase.
Differences in the development procedure: There are no
differences between the models in the procedure requirement.
Differences in scope of issues: Figure 5 shows that the Spiral
Model has a simulation phase and prototyping for construction of
programs. These types contribute with the evaluation of risks and
less maintenance and code improvement. Prototyping influences
directly in the construction of the programs based on the
simulations accomplished in the prototype by the customer. The
Waterfall Model does not specifically treat this technique.