Waterfall, Agile, and Rad Software

First, the waterfall model was the first process model to be introduced. It is very easy to operate. In this model, each phase must be completed before the next phase can begin. There is no overlapping in the phases. It’s the earliest SDLC approach that was used for software development. Some advantages of using the waterfall model is that it is simple and easy to comprehend and use. Since one phase is done at one time, it is easy to maintain. Phases are processed and completed one at a time and they do not overlap. Waterfall model works well for smaller projects where requirements are very well understood. The results are very well documented. Some disadvantages to the waterfall model is that it cannot adopt the changes in requirements. It is very hard to move back to another phase. Like let’s say during a certain stage it needs to go back to a previous stage. It would be very difficult to do so. It also does not work for long and ongoing projects.

Second, The agile model. The Agile SDLC model is a combination of iterative and incremental process models with focus on process adaptability and customer satisfaction by rapid delivery of working software product. Agile Methods break the product into small incremental builds. These builds are provided in iterations. Each iteration typically lasts from about one to three weeks. Every iteration involves cross functional teams working simultaneously on various areas. The advantage of an Agile model is that it is a very realistic approach o software development. Little to no planning is required, and it is easy to manage. It delivers early partial working solutions. And it gives flexibility to developers. Some disadvantages of the Agile model are that it is not suitable for handling complex dependencies. There is more risk of sustainability, maintainability and extensibility. There is a very high individual dependency, since there is minimum documentation generated. Also, transfer of technology to new team members may be difficult due to lack of documentation.

Third, the RAD model. Rapid Application Development (RAD) is a software development method that uses minimal planning in favor of rapid prototyping. The functional modules are developed simultaneously as prototypes and are integrated to make the complete product for faster product delivery. The customer gets early visibility in the software and can provide feedback on design, delivery, and other requirements. Some advantages of the RAD model are that it reduces development time as all prototypes are developed in parallel. It Increases reusability of components and quick initial reviews occur. It encourages customer feedback as the customer gets early visibility. And it Increases reusability of components. Some disadvantages of this model are that it depends on a strong team and individual performances for identifying business requirements. It requires highly skilled developers and designers. It cannot be used for cheaper projects as cost of modeling and automated code generation may be very high.