Which SDLC and Why?
Which Software Development Life Cycle and Why?
The Waterfall Model is the oldest and most well-known SDLC model. What are good candidate software development projects for the the Waterfall Model? Systems that have well-defined and understood requirements are a good fit for the Waterfall Model. The SDLC model has seven stages which each must be completed in order, before the next phase begins, the phase before it must be complete provides a strategic foundation in which a company can either update its existing system, or a company can create an entirely new system from scratch. The project cost for a the Waterfall Model is considerably less than other SDLCs because less resources and time are spent. The advantage of the the Waterfall Method is if the project is on a small to medium scale with simple to mediocre complexity and is short in duration. The risk of project failure is low.
The major weakness of the the Waterfall Model is that after project requirements are gathered in the first phase, there is no formal way to make changes to the project as requirements change or more information becomes available to the project team. Because requirements almost always change during long development cycles, often the product that is implemented at the end of the process is obsolete as it goes into production. The the Waterfall Model is a poor choice for software development projects where requirements are not well-known or understood by the development team. It might not a good model for complex projects or projects that take more than a few months to complete. The risk of project failure is to be considered in these circumstances.
In today’s business environment, the the Spiral Model is the most used SDLC model. Iteration to the software development life cycle was introduced in the the Spiral Model. The development team starts with a small set of requirements and goes through each development stage (except Installation and Maintenance) for those set of requirements. Based on lesson learned from the initial iteration (via a risk analysis process), the development team adds functionality for additional requirements in ever-increasing “spirals” until the application is ready for the Installation and Maintenance stage (production). Each of the iterations prior to the production version is a prototype of the application. The advantage of the the Spiral Model over the the Waterfall Model is that the iterative approach allows development to begin even when all the system requirements are not known or understood by the development team. As each prototype is tested, user feedback is used to make sure the project is on track. The risk analysis step provides a formal method to ensure the project stays on track even if requirements do change.
The disadvantage of the the Spiral Model is the draw and cost of the resources of the firm to maintain constant communication with the client and the development team, and then proceeding with verification processes. Development morale can be affected if the same requirements and functionality are continuously revisited. The length of the project may vary in length due to the amount of change in requirements. The risk of the project failure is low.