Testing_106 : SDLC Model:Iterative & Incremental Model

3) Incremental/Iterative Model :

• This model does not attempt to start with full specification of requirements. Multiple development cycles take place here, making the life cycle a 'multi-waterfall' cycle. Cycles are divided up into smaller, more easily managed iterations. Each iteration passes through the requirements, design, implementation and testing phases.
• A working version of software is produced during the first iteration, so you have working software early on during the software life cycle. Subsequent iterations build on the initial software produced during the first iteration.

Key Points :

• Development and delivery is broken down into increments.
• Each increment delivers part of the required functionality.
• Once the development of an increment is started, the requirements are frozen.
• Requirements for later increments can continue to evolve.

Advantages :

• The versions are provided after iteration of the incremental  model.
• After using first iterated model, user can give their suggestion and demand for changes.
• Easy to test as testing is done in iteration as per requirement.

Limitation :

•  More management attention is required due to frequent changes in requirements.

4) Rapid Application Development Model :

• RAD enables creation of fully functional software within a very short time.
• If the requirements are well understood and defines, and the project scope is constraint, the RAD process enables a development team to create a fully functional system within very short time period.
• For large projects RAD require highly skilled engineer in the team. Both end customer and developer should be committed to complete the system in a much abbreviated time frame.
• If commitments is lacking, RAD will fail.

Advantages :

• RAD produces systems more quickly and to a business focus, this approach tends to produces systems at a lower cost.
• Provides the ability to rapidly change system design as demanded by users.

Limitations :

• Due to inappropriate information, developed system might be misaligned.
• Project may end up with more resources than needed.
• Due to hurry, there may inconsistent designs within and across system.

Next Model : Spiral Model