3. 3
• The Waterfall model is a linear, sequentional .
• Requirement should be clear by client before going
to next phase of design.
• Testing is carried out once the code has been fully
developed.
• Each work-product or activity is completed before
moving on to next.
• In waterfall model the defect were found very late
in the development life cycle as test team was not
involved from the beginning of the project.
Waterfall
5. Pros of waterfall modal
• Each stage has well defined & understood
milestone.
• Requirement is clear before development
starts.
• Each phase is completed in specified period
of time after that it moves to next phase.
• As its linear model, it’s easy to implement &
simple to use .
• Each phase proper documentation is followed
for the Quality of the development.
6. Cons of waterfall modal
• The major disadvantage of the waterfall
model is one of its greatest advantages.
You cannot go back a step.
• Requirements can not be changed during
development process.
7. V & V modal
• The V model (Validation & Verification model)
is a modified version of the Waterfall modal.
• The V-model contacts each development
activity with a test or validation at the same
level of abstraction.
• V model emphasizes on performance and
correctness.
• Well suited to a project that has low risk in
the areas of user interface and routine
requirements, but high risk in budget.
9. Pros of V modal
• V model is understandable and very
easy to use.
• Each phase has definite deliverables.
• Higher possibility of achievement over
the waterfall model due to the
development of test plans early on
during the life cycle.
• Works well for small projects where
obligations are simply understood.
10. Cons of V modal
• It is very inflexible, like the waterfall
model.
• Adjusting scope is difficult and
expensive.
• Model doesn’t offer a clear path for
problems found during testing stages.
11. Spiral model
• The spiral model of software appears like a
spiral with many loops.
• Over each loop, one or more features of the
product are elaborated and analyzed and the
risks at that point of time are identified and are
resolved through prototyping.
• The spiral model is similar to the incremental
model, with more emphases placed on risk
analysis.
• The spiral model has four phases:
Planning
Risk Analysis
Engineering
Evaluation
12. Spiral model
• A software development repeatedly passes
through these phases in iterations.
• The baseline spiral, starting in the planning
phase, requirements is assembled and risk is
judged .Each succeeding spiral constructs on
the baseline spiral.
• Requirements are gathered during the planning
phase.
• In the risk analysis phase, a process is
undertaken to identify risk and alternate
solutions. A prototype is produced at the last
part of the risk analysis phase.
13. Spiral model
• Software is produced in the
engineering phase, along with testing
at the last of the phase.
• The evaluation phase permits the
customer to evaluate the productivity of
the project to date before the project
carry on to the next spiral.
15. Pros of spiral modal
• This model provide high amount of risk
analysis.
• Risks are unambiguously evaluate and
resolved throughout the process.
• It Focus on early bug finding and design
flaws.
• Best for large and mission-critical projects.
• Software is produced early in the
software life cycle.
16. Cons of spiral modal
• Can be an expensive model to use.
• Risk analysis needs extremely specific
expertise.
• Project’s success is highly reliant on the risk
analysis phase.
• Does not work well for smaller projects.
• The spiral model, being the best of these
models, is suitable for development of
technically challenging and large projects
prone to several kinds of risks. But this model
is generally not used due to its complexity.
17. Conclusion
• If the requirements are known before hand and
well understood and we want full control over the
project at all time, then we can use waterfall
model. V-shaped Model has higher chance of
success over the waterfall model due to the
development of test plans during the life cycle. It
works well for small projects where requirements
are easily understood Spiral model is good for
large and mission critical projects where high
amount of risk analysis is required like launching
of satellite..