The system development life cycle model consists of the following activities:
i) Preliminary investigation:
It is undertaken when users come across a problem or opportunity and submit a formal request for a new system to the MIS department. This activity consists of three parts: request clarification, feasibility study and request approval. Generally the requests, which are submitted to the MIS
department, are not clearly stated. Hence, before any system investigations can be considered, the system request must be examined to determine precisely what the originator wants. Thereafter, the analyst tries to determine whether the system requested is feasible or not. Aspects of technical, economic and operational feasibility of the system are covered in the feasibility study. The third part of investigation relates to approval of the request. Not all requested systems are desirable or feasible. Based on the observations of the analyst, the management decides, which system should be taken up for development.
ii) Requirements analysis or system analysis:
If, after studying the result of preliminary investigation management decides to continue the development process, the needs of the users are studied. Analysts work closely with employees and managers of the organization for determining information requirements of the users. Several fact-finding techniques and tools are used for understanding the requirements. As details are gathered, the analysts study the present system to identify its problems and shortcomings and identify the features, which the new system should include to satisfy the new or changed user application environment. This step is also referred to as ‗‗system analysis‘‘.
iii) Design of the system:
During system design, the user requirements that arose from analyzing the user application environment are incorporated into a new systems design. The design of an information system produces the details that state how a system will meet the requirements identified above. The analysts design various reports/outputs, data entry procedures, inputs, files and database. He also selects file structures and data storage devices. These details design specification are then passed on to the programming staff so that software development can begin.
iv) Acquisition and development of software:
After the system design details are resolved, such resources need as specific type of hardware, software and services are determined. Subsequently, choices are made regarding, which products to buy or lease from which vendors. Software developers may install purchased software or they may write new, custom-designed programs. The choice depends on many factors such as time, cost and availability of programmers. The analyst works closely with the programmers if the software is to be developed in-house. During the phase, the analyst also works with users to develop worthwhile documentation for software, including various procedure manuals.
v) Systems testing:
Before the information system can be used, it must be tested. System testing is done experimentally to ensure that the software does not fail, i.e., it will run according to its specifications and in the way user expect. Special test data are input for processing, and results examined. If it is found satisfactory, it is eventually tested with actual data from the current system.
vi) Implementation and maintenance:
After the system is found to be fit, it is implemented with the actual data. Hardware is installed and users are then trained on the new system and eventually work on it is carried out independently. The results of the development efforts are reviewed to ensure that the new system satisfies user requirements. After implementation, the system is maintained, it is modified to adapt to changing users and business needs so that the system can be useful to the organization as long as possible.