At the initial time of business computing, information system development was a muddled procedure commonly producing discouraging results. To progress the quality of information systems and services an approach for system development life cycle (SDLC) is developed. The system development life cycle can be considered in five phases. Each phase in intended to address key issues and to produce outcome, which form the input for the next phase. The phases are as follows:

1. Preliminary investigation – determining the problem and scope
2. Analysis – understanding the existing system
3. Design – planning the new system
4. Development – doing the work to bring the new system into working condition
5. Implementation – converting to the new system

System development life cycle and activities:

Phases	Activities
Preliminary investigation	Problem definition Nature of problem Problem scope Objectives of the problem Feasibility test Report of the preliminary investigation
System Analysis	Data gathering Written documents Interviews Questionnaires Observation Sampling Data analysis Charts Tables System requirement Report to the management
System design	Preliminary design Prototyping Detail design Output requirement Input requirement Files and databases System processing Controls and backup
System Development	Scheduling activities Programming Testing
Implementation	Training Equipment conversion File conversion System conversion Audition Evaluation Maintenance

Waterfall Model:

The SDLC described above is a systematic step by step by process. However, it is not always wise to keep going if work in a later stage turns up problems with the work performed in an earlier stage. For example, in the system analysis phase, the analyst may discover that the problem has not been formulated correctly. To overcome this problem, the most popular waterfall model builds improvement pathways into the model that allow a return to a previous phase. It is the widely used way to implement the system development life cycle.