5. “Spiral model is a combination of sequential
and prototype model. This model is best
used for large projects which involves
continuous enhancements.”
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7. Spiral Model
(Brief History)
The spiral model was defined by Barry Boehm in his
1988 article A Spiral Model of Software Development
and Enhancement. This model was not the first model
to discuss iterative development, but it was the first
model to explain why the iteration matters.
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10. Phases
(Planning)
Planning:
In this phase Software analyst communicate with
the clients and the necessary requirements such
as Business Requirements and System
Requirements are gathered.
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11. Phases
(Risk Analysis)
Risk Analysis:
In this phase analyst assume all the possible
risks that could be occurred during future
development and alternative solutions are
proposed to overcome future risk.
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13. Phases
(Evaluation)
Evaluation:
In this phase customer/clients evalute the
developed software or the system. After
evaluation if customer wishes for more
features to add in the software then the
process of itaration is continued.
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16. Spiral Model
(Application)
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1. When risk evaluation is important for a project.
2. For medium to high-risk projects.
3. Long-term project commitment because of potential changes to
economic priorities as the requirements change with time.
4. Customer is not sure of their requirements which is usually the
case.
5. Requirements are complex and need evaluation to get clarity.
6. New product line which should be released in phases to get enough
customer feedback.
7. Significant changes are expected in the product during the
development cycle.
18. Spiral Model
(Pros & Cons)
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This method is consistent with approaches that have multiple software
builds and releases and allows for making an orderly transition to a
maintenance activity. Another positive aspect is that the spiral model
forces early user involvement in the system development effort.
On the other side, it takes very strict management to complete such
products and there is a risk of running the spiral in indefinite loop. So the
discipline of change and the extent of taking change requests is very
important to develop and deploy the product successfully
19. Spiral Model
(Pros)
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1. Changing requirements can be accommodated.
2. Allows for extensive use of prototypes
3. Requirements can be captured more accurately.
4. Users see the system early.
5. Development can be divided into smaller parts and more risky parts
can be developed earlier which helps better risk management.
20. Spiral Model
(Cons)
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1. Management is more complex.
2. End of project may not be known early.
3. Not suitable for small or low risk projects and could be expensive for
small projects.
4. Process is complex.
5. Spiral may go indefinitely.
6. Large number of intermediate stages requires excessive
documentation.