Incremental Model with Unified Process

Software Development Models

• The development models are the various processes or methodologies that are being selected for the development of the project depending on the project’s aims and goals.

• There are many development life cycle models that have been developed in order to achieve different required objectives.

There are various Software development models or methodologies. They are as follows:

• Waterfall model• V model• Incremental model• RAD model (Rapid Application Development)• Agile model• Iterative model• Spiral model

Software Development Models

Incremental Model• The incremental build model is a method of

software development where the model is designed, implemented and tested incrementally (a little more is added each time) until the product is finished.

• It involves both development and maintenance.

• The product is defined as finished when it satisfies all of its requirements.

Advantages• First increment satisfies most critical requirement-

possibility to use software immediately.

• It is easier to test and debug during a smaller iteration.

• This model is more flexible – less costly to change scope and requirements.

Disadvantages• Hard to decide on size of each increments.

• Progress can be hard to judge and problems hard to find because there is no documentation to demonstrate what has been done.

• Total cost is higher than waterfall.

Tasks in Incremental Model

Tasks Involved These tasks are common to all the models• Communication: helps to understand the objective.• Planning: required as many people (software teams)

work on the same project but different function at same time.

• Modeling: involves business modeling, data modeling, and process modeling.

• Construction: this involves the reuse software components and automatic code.

• Deployment: integration of all the increments.

Unified Process• The Unified Software Development Process or

Unified Process is a popular iterative and incremental software development process framework.

• The best-known of the Unified Process is the Rational Unified Process (RUP).

• Other examples are OpenUP and Agile Unified Process .

Unified Process CharacteristicsIterative and Incremental• The Elaboration, Construction and Transition phases

are divided into a series of iterations. Each iteration results in an increment, which is a release of the system that contains added or improved functionality compared with the previous release.

• Although most iterations will include work in most of the process disciplines (e.g. Requirements, Design, Implementation, Testing).

Use Case Driven

• In the Unified Process, use cases are used to capture the functional requirements and to define the contents of the iterations.

• Each iteration takes a set of use cases or scenarios from requirements all the way through implementation, test and deployment.

Architecture Centric• The Unified Process insists that architecture sit at

the heart of the project team's efforts to shape the system. Since no single model is sufficient to cover all aspects of a system, the Unified Process supports multiple architectural models and views.

• One of the most important deliverables of the process is the executable architecture baseline which is created during the Elaboration phase. This partial implementation of the system serves to validate the architecture and act as a foundation for remaining development.

When to use the Incremental model:

• This model can be used when the requirements of the complete system are clearly defined and understood.

• Major requirements must be defined; however, some details can evolve with time.

• There is a need to get a product to the market early.• A new technology is being used• Resources with needed skill set are not available• There are some high risk features and goals.

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