The Spiral Model is a software development process that divides projects into iterations. It consists of four phases - Planning, Risk Analysis, Engineering, and Evaluation - that are repeated within each iteration. In the Planning phase, requirements are gathered. Risk Analysis involves creating prototypes to identify risks. Engineering is when software is developed and tested. Evaluation has customers assess the software and plan the next iteration. The Spiral Model is suited for medium-high risk projects where requirements are complex and changing.

1. Spiral Model

2. Spiral Model

3. Application Of Spiral Model

4. FOUR PHASES OF SPIRAL MODEL4
• Planning
• RiskAnalysis
• Engineering
• Evalution

5. PLANNING
• This phase starts with gathering the business
requirements in the baseline spiral.
• Planning includes estimating the cost, schedule
and resources for the iteration.
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6. RISK ANALYSIS
• In this phase analyst assume all the possible risks
that could be occurred during future
development.
• A prototype is produced at the end ofthe risk
analysis phase.
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7. ENGINEERING
• In this phase software is developed,
along with testing at the end of the
phase.
• Hence this phase includes testing,
coding and deploying software at the
customer site.
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8. EVALUATION
• In this phase, Customers evaluate the so
far developed version of the software.
• In the end, planning for the next phase
is started.
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9. When to use Spiral Model
 Whencostsandriskevaluationisimportant.
 Formediumtohigh-risk projects.
 Users areunsureoftheirneeds.
 Requirements are complex.

10. Advantages
 Changing requirements can be accommodated.
 Allowsforextensiveuseofprototypes.
 Requirementscanbecaptured more accurately.
 Users seethesystemearly.
 Early and frequent feedback from users.

11. Disadvantages
 End ofprojectmaynotbeknownearly.
 Not suitableforsmallorlowrisk projectsand could be
expensiveforsmallprojects.
 Process iscomplex.
 Spiralmaygo indefinitely.

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