What is the software development lifecycle (SDLC)? Phases and models

The Software Development Life Cycle (SDLC) is a structured methodology used by software development teams to produce cost-effective and high-quality software products through a series of phases: planning, defining requirements, prototyping, implementation, integration and testing, deployment, and operations and maintenance. Initially detailed in Geoffrey Elliott's book "Global Business Information," the SDLC has evolved into various models, such as the traditional Waterfall model, characterized by its linear and sequential phase progression, and the Spiral model, which is risk-driven and combines elements of both the Waterfall and Iterative models. While the Waterfall model is noted for its simplicity and structured documentation, it lacks flexibility, making changes difficult once a phase is completed. Conversely, the Spiral model offers greater flexibility and risk management but requires more expertise and can be costlier. Despite the rise of more adaptive Agile methodologies, understanding the SDLC and its models remains valuable for product managers and teams aiming to develop processes tailored to their specific needs.