Comparative study of

waterfall , v&v and spiral

modal

Software development

Software Development

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

Life cycle of Waterfall modal

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.

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.

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.

Life cycle v & v modal

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.

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.

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

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.

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.

Spiral model

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.

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.

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..

Thank you