SYSTEM DEVELOPMENT MODELSIntroductionA system model is a conceptual representation of the outlay of the entire system. It represents the multiple points of view and needs that should be incorporated into system development. There are different types of system development model, each of which has advantages and disadvantages. Waterfall model is one of the models used in system software development. As the name suggests, it has a characteristic resemblance to the geographical waterfall in its functioning. It assumes the linear and sequential system development model in execution. The development of the system is classified into each phase with distinct and varied objectives. Once a stage is passed, development proceeds to the next stage without reverse development in the previous focus (Bergen, 2004). Development stages include; Requirements, design, implementation, verification and maintenance. Separating development phases in the form of phases presents challenges and opportunities alike. It becomes easy to set deadlines for the different phases and easily monitor the execution of the set objectives. Furthermore, it is easy to understand and comprehend as the phases are distinct with different objectives (Johnson, 2007). On the other hand, it is inflexible since it does not allow reflection or modification of the previous stage. This makes it insensitive to advances in several fields. Apart from the waterfall method, system developers have another option to adopt the Agile method of system development. The agile method derives its meaning from the superficial meaning of agile which means fast. As a result, agile development methodology seeks to provide numerous opportunities to directly evaluate its system development models (Johnson, 2007). On the other hand, the system methodology requires more time and money than others. As a result, it is normally infamous compared to others. In the recent past, system lifecycle modeling has witnessed some changes and trends that are worth noting. First, most organizations have moved from acquiring software internally to purchasing it off-the-shelf as an off-the-shelf product or purchasing it from companies that build specific, bespoke software. Even in the recent past, Information Technology, through the systems developed, has become the efficient approach for managing data and various industrial processes (Bergenti, 2007). Companies have shifted focus to system development but have ventured far into purchasing tested brands and already customized systems.