Waterfall Model Simplest software model Sequential design process Clear project objectives Stable project requirements. Concrete and clear approach to software development Amount of resources required is very minimal i.e. cheaper
Waterfall Model Strengths of Waterfall Model Minimizes planning overhead since it can be done up front. Structure minimizes wasted effort, so it works well for technically weak or inexperienced staff.
Waterfall Model Weaknesses of Waterfall Model Inflexible Onlythe final phase produces a non documentation deliverable Backing up to address mistakes is difficult.
Prototype Model Overcomes limitations of Waterfall model Prototype is made which is further modified as per the requirement of the customer
Prototype Model Strengths of Prototype Model Early functionality. Provides a process to perfect the requirements definition. Provides risk control. Documentation focuses on the end product not the evolution of the product.
Prototype Model Weaknesses of Prototype Model Less applicable to existing systems than to new, original development. Bad reputation among conservatives as a "quick and dirty" method. Suffers from bad documentation Sometimes produces a system with poor performance. Tendency for difficult problems to be pushed to the future so that the initial promise of the prototype is not met by subsequent products plans.
Spiral Model combines elements of both design and protoypein-stages
Agile Model It is an enhanced development software, not a alternative option. It is a distinct software development method. Its an iterative method.
Agile Model Advantages Agile by definition would naturally refer to something which is quick and easy to do. They are test-driven software development. It provides advice for how to be effective as a modeler.
Agile Model Disadvantages Difficult to apply where there are large team members. May increase the complexity of the system as scope of the system may expand beyond original plan. It does not define detailed procedures for how to create a given type of model.