The spiral model combines elements of the prototype and waterfall models. It involves iterating through phases of planning, risk analysis, engineering, and customer evaluation. The model aims to identify and mitigate risks early through prototyping. Key advantages include risk avoidance and the ability to add functionality later, though it can be costly due to extensive risk analysis needs.

1. SPIRAL MODEL
(SDLC)
Inam Ul-Haq
Lecturer in Computer Science
University of Education, Okara Campus
inam.bth@gmail.com
Submitted by:
Hira Mehar
Roll No. 3006
BS-IT-Eve
IV Semester
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2. Introduction
In this system development method, we combine
the features of both, prototype model and
waterfall model.
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3. Introduction
•In spiral model we can arrange all the
activities in the form of a spiral
•A spiral model is divided into number
of framework activities, called task
regions
•Typically, there are between three and
six task regions
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4. Why Spiral Model ???
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5. Why Spiral Model ???
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6. Why Spiral Model ???
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7. History
•The spiral model was
defined by Barry Boehm
in his 1988 article.
•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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8. Spiral Model
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9. Phases
•Customer Communication
•Planning
•Risk Analysis
•Engineering
•Customer Evaluation
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10. Customer Communication
•Includes understanding
the system
requirements by
continuous
communication
between the customer
and the system analyst.
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11. Planning
• Task required to define resources,
timelines and other project related
information
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12. Risk Analysis
• In the risk analysis phase, a
process is undertaken to
identify risk and alternate
solutions. A prototype is
produced at the end of the
risk analysis phase. If any risk
is found during the risk
analysis then alternate
solutions are suggested and
implemented. 12
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13. Engineering
•In this phase software
is developed, along
with testing at the
end of the phase.
Hence in this phase
the development and
testing is done
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14. Customer Evaluation
• This phase allows the customer to
evaluate the output of the project to date
before the project continues to the next
spiral
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15. Advantages
High amount of risk analysis hence,
avoidance of risk is enhanced.
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16. Advantages
Good for mission critical projects.
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17. Advantages
Strong approval and documentation control.
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18. Advantages
Additional functionality can be added at a
later date.
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19. Disadvantages
Can be costly model to use.
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20. Disadvantages
Risk analysis requires highly specific expertise.
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21. Disadvantages
Project`s success is highly dependent on the
risk analysis phase.
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22. Strengths
• Provides early indication of
insurmountable risks, without much
cost
• Users see the system early because of
rapid prototyping tools
• Critical high-risk functions are
developed first
• The design does not have to be
perfect
• Users can be closely tied to all
lifecycle steps
• Early and frequent feedback from
users
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23. Conclusions
• The risk-driven nature provides adaptability for a full range of
software projects.
• The model has been successful in a large application, the
TRW-SPS.
• The model is not yet fully elaborated.
• Even partial implementations of the model, such as the risk
management plan, are compatible with the other process
models.
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24. References
• www.slideshare.net
• www.buzzle.com
• www.cavehill.uwi.edu
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