Write a note on the following: i) Linear or Waterfall Model; ii) Iterative/ Incremental or Fountain Model; iii) Prototyping/ Evolutionary Model; iv) Spiral model.

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written 5.7 years ago by

hetalgosavi • 1.6k

• modified 5.7 years ago

Each phase is executed in sequence. It establishes a formal analysis and design methodology with highly structured development phases.
The flow is unidirectional. Output of one phase serves as input to next phase.
The feature of linear model is that the bugs in the current design are not corrected immediately and development proceeds with current design.
The fixing of bug is done in support and deployment phase.
Advantages: Rich documentation, Easy project management, Good control over cost and schedule.
Drawbacks: No design implementation is done. It works with assumption. Risk analysis is done only once. Working model is available at the end and bug fixes are done in support phase.

Waterfall Model

It follows analysis, design and implementation. Evaluate the product and cycle back trough and conduct analysis, design and repeat the cycle.
It is a cascade of series of linear models. Here, requirements are known at the beginning and are derived into groups.

Advantages –

Provides good development cycle feedback at each function/ feature implementation and data can be used as reference for similar product development in future.
More responsive to changing user needs.
Provides a working model with minimum features at first cycle itself.
Less manufacturing risk.
Product development can be stopped at any stage.

Drawbacks –

Here, product is developed in multiple cycles. It produces refined prototype of the product at the end of each cycle.
There is no commercial deployment at each cycle’s end.
After requirement analysis, design for first prototype is made, development is started.
On finishing the prototype, it is sent to customer for evaluation. The customer evaluates and gives the feedback to developer in terms of shortcomings and improvements needed.
The developer refines the product according to customer’s expectation and repeats prototype development process.
After multiple iterations product is delivered to the customers and launched.

Advantages –

Drawbacks –

Deviation from expected cost and schedule due to requirement refinement.
Increased project management.
Minimal documentation on each prototype may create problem in backward prototype traceability.
Increased configuration management activities.

This model combines the elements of linear and prototyping models to give risk minimized EDLC model.
It is developed by Barry Boehm in 1988. It starts with project definition and traverse through all phases.
This model is suited for the development of complex products and situations where requirements and technology changes.
The prototype model is evaluated by customers against various parameters. The final product is built based on final prototype on agreement with client.
The activities are as follows –

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