SOFTWARE DEVELOPMENT LIFE CYCLE MODELS
SOFTWARE DEVELOPMENT LIFE CYCLE MODELS
1)WATERFALL MODEL
2)V-MODEL
3)ITERATIVE MODEL
4)RAD MODEL
5)SPIRAL MODEL
6)BIG BANG MODEL
WATERFALL MODEL:
Waterfall Model - Application
Every software developed is different and requires a suitable SDLC approach to be followed based on the internal and external factors. Some situations where the use of Waterfall model is most appropriate are −
Requirements are very well documented, clear and fixed.
Product definition is stable.
Technology is understood and is not dynamic.
Waterfall Model - Advantages
Some of the major advantages of the Waterfall Model are as follows −
* Simple and easy to understand and use
* Easy to manage due to the rigidity of the model. Each phase has specific deliverables and a review process.
* Phases are processed and completed one at a time.
* Well understood milestones.
*Easy to arrange tasks.
Waterfall Model - Disadvantages :
* High amounts of risk and uncertainty.
* Not a good model for complex and object-oriented projects.
* Poor model for long and ongoing projects.
*It is difficult to measure progress within stages.
*Cannot accommodate changing requirements.
2)V-Model
The V-model is an SDLC model where execution of processes happens in a sequential manner in a V-shape. It is also known as Verification and Validation model.
The V-Model is an extension of the waterfall model and is based on the association of a testing phase for each corresponding development stage. This means that for every single phase in the development cycle, there is a directly associated testing phase.
V- Model ─ Applications
* Requirements are well defined, clearly documented and fixed.
*Product definition is stable.
*Technology is not dynamic and is well understood by the project team.
V-Model - Pros and Cons
The advantages of the V-Model method are as follows −
* This is a highly-disciplined model and Phases are completed one at a time.
*Works well for smaller projects where requirements are very well understood.
* Simple and easy to understand and use.
The disadvantages of the V-Model method are as follows −
* High risk and uncertainty.
* Not a good model for complex and object-oriented projects.
* Poor model for long and ongoing projects.
3)ITERATIVE MODEL :
Iterative Model - Application
* Major requirements must be defined; however, some functionalities or requested enhancements may evolve with time.
* There is a time to the market constraint.
* A new technology is being used and is being learnt by the development team while working on the project.
Iterative Model - Pros and Cons
The advantages of the Iterative and Incremental SDLC Model are as follows −
* Some working functionality can be developed quickly and early in the life cycle.
* Results are obtained early and periodically.
* Testing and debugging during smaller iteration is easy.
* Easier to manage risk - High risk part is done first
The disadvantages of the Iterative and Incremental SDLC Model are as follows −
* More resources may be required.
* Not suitable for smaller projects.
* Management complexity is more.
* End of project may not be known which is a risk.
4)RAD MODEL
Rapid application development is a software development methodology that uses minimal planning in favor of rapid prototyping.
A prototype is a working model that is functionally equivalent to a component of the product.
Application Generation
The actual system is built and coding is done by using automation tools to convert process and data models into actual prototypes.
RAD Model - Pros and Cons
The advantages of the RAD Model are as follows −
*Changing requirements can be accommodated.
*Progress can be measured.
*Iteration time can be short with use of powerful RAD tools
The disadvantages of the RAD Model are as follows −
* Dependency on technically strong team members for identifying business requirements.
* Only system that can be modularized can be built using RAD.
* Requires highly skilled developers/designers.
5)SPIRAL MODEL :
Spiral Model Application
* When there is a budget constraint and risk evaluation is important.
* For medium to high-risk projects.
* Requirements are complex and need evaluation to get clarity.
* New product line which should be released in phases to get enough customer feedback.
* Significant changes are expected in the product during the development cycle.
Spiral Model - Pros and Cons
* Changing requirements can be accommodated.
* Allows extensive use of prototypes.
* Requirements can be captured more accurately.
6)BIG BANG MODEL
Big Bang Model - Pros and Cons
The advantage of this Big Bang Model is that it is very simple and requires very little or no planning. Easy to manage and no formal procedure are required.
The advantages of the Big Bang Model are as follows −
*This is a very simple model
*Little or no planning required
*Easy to manage
*Very few resources required
The disadvantages of the Big Bang Model are as follows −
*Very High risk and uncertainty.
*Not a good model for complex and object-oriented projects.
*Poor model for long and ongoing projects.
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