Page: Evolutionary Process Models
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  • Evolutionary models are iterative type models.

  • They allow to develop more complete versions of the software.

Following are the evolutionary process models.

  1. The prototyping model

  2. The spiral model

1. The Prototyping model

  • Prototype is defined as first or preliminary form using which other forms are copied or derived

  • Prototype model is a set of general objectives for software.

  • It does not identify the requirements like detailed input, output

  • It is software working model of limited functionality

  • In this model, working programs are quickly produced.

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The different phases of Prototyping model are: 

  1. Communication In this phase, developer and customer meet and discuss the overall objectives of the software. 

  2. Quick design

  • Quick design is implemented when requirements are known.

  • It includes only the important aspects like input and output format of the software.

  • It focuses on those aspects which are visible to the user rather than the detailed plan.

  • It helps to construct a prototype.

3. Modeling quick design

  • This phase gives the clear idea about the development of software because the software is now built.

  • It allows the developer to better understand the exact requirements.

4. Construction of prototype

  • The prototype is evaluated by the customer itself.

5. Deployment, delivery, feedback

  • If the user is not satisfied with current prototype then it refines according to the requirements of the user.

  • The process of refining the prototype is repeated until all the  requirements of users are met.

  • When the users are satisfied with the developed prototype then the system is developed on the basis of final prototype.

Advantages of Prototyping Model

  • Prototype model need not know the detailed input, output, processes, adaptability of operating system and full machine interaction.

  • In the development process of this model users are actively involved.

  • The development process is the best platform to understand the system by the user.

  • Errors are detected much earlier.

  • Gives quick user feedback for better solutions.

  • It identifies the missing functionality easily. It also identifies the confusing or difficult functions.

Disadvantages of Prototyping Model:

  • The client involvement is more and it is not always considered by the developer.

  • It is a slow process because it takes more time for development

  • Many changes can disturb the rhythm of the development team.

  • It is a thrown away prototype when the users are confused with it.


2. The Spiral model

  • Spiral model is a risk driven process model.

  • It is used for generating the software projects.

  • In spiral model, an alternate solution is provided if the risk is found in the risk analysis, then alternate solutions are suggested and implemented

  • It is a combination of prototype and sequential model or waterfall model.

  • In one iteration all activities are done, for large project's the output is small.

The framework activities of the spiral model are as shown in the following figure.

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Advantages of Spiral Model

  • It reduces high amount of risk.

  • It is good for large and critical projects.

  • It gives strong approval and documentation control.

  • In spiral model, the software is produced early in the life cycle process.

Disadvantages of Spiral Model

  • It can be costly to develop a software model

  • It is not used for small projects.

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modified 7 weeks ago by gravatar for Sanket Shingote Sanket Shingote ♦♦ 250 written 3 months ago by gravatar for stanzaa37 stanzaa370
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