<P> The product life cycle describes the process for building information systems in a very deliberate, structured and methodical way, reiterating each stage of the product's life . The systems development life cycle, according to Elliott & Strachan & Radford (2004), "originated in the 1960s, to develop large scale functional business systems in an age of large scale business conglomerates . Information systems activities revolved around heavy data processing and number crunching routines". </P> <P> Several systems development frameworks have been partly based on SDLC, such as the structured systems analysis and design method (SSADM) produced for the UK government Office of Government Commerce in the 1980s . Ever since, according to Elliott (2004), "the traditional life cycle approaches to systems development have been increasingly replaced with alternative approaches and frameworks, which attempted to overcome some of the inherent deficiencies of the traditional SDLC". </P> <P> The system development life cycle framework provides a sequence of activities for system designers and developers to follow . It consists of a set of steps or phases in which each phase of the SDLC uses the results of the previous one . </P> <P> The SDLC adheres to important phases that are essential for developers--such as planning, analysis, design, and implementation--and are explained in the section below . This includes evaluation of the currently used system, information gathering, feasibility studies, and request approval . A number of SDLC models have been created, including waterfall, fountain, spiral, build and fix, rapid prototyping, incremental, synchronize, and stabilize . The oldest of these, and the best known, is the waterfall model, a sequence of stages in which the output of each stage becomes the input for the next . These stages can be characterized and divided up in different ways, including the following: </P>

During which phase of the sdlc is the system made operational in a production environment