The success of a system relies on the approach of building it. If development approach is right then system will work successfully. Figure below portrays a System Development Life Cycle. System development life cycle (SDLC) is a standard methodology for development of Information System. It principally comprises four phases: System Analysis, System Design, System Construction & Implementation and System Support. Each phase comprises inputs, tasks and outputs. Traditional SDLC was strictly sequential. Developers first complete the previous phase then start the subsequent phase. Though now concept of Repository is introduced in SDLC and it is termed as FAST methodology where work is done across shared repository. It means that all inputs and outputs of phases should be stored in the repository. At any instance developers can backtrack to preceding phase and they may also work on two phases concurrently. 

Figure: System Development Life Cycle