ABSTRACT
The process of developing software has become more complex over the years. This has led to the development of multiple models of the software development lifecycle (SDLC). The product lifecycle lasts the entire life of the product, from initial concept, through retirement, but the project lifecycle only lasts as long as it takes to produce the approved deliverables. The Waterfall Model is the original SDLC model. Each phase is clearly defined and must be completed prior to moving on to the next. The Spiral Model is a modified version of the waterfall designed to decrease the risks surrounding software development by the use of prototypes and risk analysis. The Incremental Model builds software during each of the steps. Each step, or increment, goes through the same processes until the final system is complete. Agile software development allows for requirements and deliverables to evolve through a collaborative approach.
