Answer – As the name suggests it is a simple process which is one way and does not have flexibility to revise the process phase already completed same as water once fall cannot jump back to its initial position. In this model one phase is completed and reviewed fully to enter the next phase. In this model phase do not overlap.
Advantages :- • It is a simple model. • Each phase is completed at a time and reviewed. • Works well with projects where the objective result is crystal clear. Specifically small projects with simple aim’s. • Such projects are generally predictable. • This model is one of the best model to be used if the requirements and the goals are very clear even the large products can be developed very effectively. If the large projects are divided in to small separate projects and then are developed with waterfall model. Researcher’s confirms that the projects will be very organized and effective in terms of resources.
Disadvantages:-
• Waterfall model is very disciplined approach and documentation is provided in each phase. Practically there is a considerable difference in the way a client understands a product as described by the specification document and the actual product. The waterfall model, depending as it does so crucially on written specification, can lead to the construction of products that simply do not meet the client’s requirements. • Not compatible to projects where requirements have high risks of uncertainty. • Once the project is in testing phase it is very difficult to go back and make the respective changes required because the concepts were not thought at the initial phase. • Minimum success rate observed for complex and object oriented projects. • Poor model for long and ongoing projects. • No working software