Many SDLC methods (System Development Life Cycle) exist that can be used by an organisation to effectively develop an information system.
A traditional SDLC is called a linear sequential model, also known as waterfall method. This model assumes that the system will be delivered in its final stages of the development life cycle.
Another SDLC method uses the prototyping model, which is often used to develop an understanding of system requirements only, without actually developing a final operational system.
More complex systems require more iterative development models to address the evolving complexity of advanced and sometimes large information system designs. Examples of these more complex models are RUP (Rational Unified Process), CBD (Component Based Development) and agile software development methods like Scrum and Extreme Programming.
The expected size and complexity of the system, development schedule, and length of a system’s life will affect the choice of which SDLC model to use.