What are the different stages of software development?

What are the different stages of software development?
Explain with examples why a program development requires systematic methods. What are the initial steps of program design?
Why should user be involved throughout the system development life cycle? Can you think of some specific examples of what might happen if the users are not involved?
Ans: A set of elements work together for a common goal is known as system i.e. education system, Police Security System, Banking System etc. Raw data is originated, processed / transmitted and received as information and the integration of it is known as information system.
To manage the existing information system by using computer is Computerized Information System(CIS). To manage Information System(MIS) we must know the structure of an organization. The structure of an organization can be leveled top to bottom as STRATEGIC --->TACTICAL ---> OPERATIONAL ---> TRANSACTION. And the data/information flow is more structured in lower level of an organization.
The various steps have to be flowed to develop a system is known as SDLC( System/Software Development Life Cycle) and they are:
SYSTEM ANALYSIS: System analysis is the analysis of the problem that the organization will try to solve with an information system. It consists of defining the problem, identifying its causes, specifying the solution, and identifying the information requirements that must be met by a system solution. The key to building any large information system is a through understanding of the existing organization and system.
FEASIBILITY STUDY: It involves a feasibility study to determine whether that solution is feasible, or achievable, given the organization's resources and constraints. Three major areas of feasibility must be address:
1. Technical Feasibility: Whether the proposed solution can be implemented with the available hardware, software, and technical resources.
2. Economic Feasibility: Whether the benefits of the proposed solution outweigh the costs.
3. Operational Feasibility: Whether the proposed solution is desirable within the existing managerial and organizational framework.
ESTABLISHING INFORMATION REQUIREMENTS :The system analyst has to define the specific information requirements that must be met by the system solution selected. At the most basic level, the information requirements of a new system involve identifying who needs what information, where, when and how. Requirements must consider economic, technical, and time constraints, as well as the goals, procedures, and decision processes of the organization.
SYSTEM DESIGN : System design shows how the system will fulfill the objective. It consists of all the specifications that give the system its form and structure. Information system design is an exacting and creative task demanding imagination, sensitivity to detail, and expert skills.
System design has three objectives. First, the system designer is responsible for considering alternative technology configurations. Second, designers are responsible for the management and control of the technical realization of system. Detailed programming specifications, coding of data, documentation, testing, and training are all the responsibility of the design staff. Third, the system designer details the system specifications that will deliver the functions identified during systems analysis.
PROGRAMMING : The process of translating design specification into software for the computer constitutes a smaller portion of the system development cycle than design and perhaps the testing activities.
TESTING : Exhaustive and thorough testing must be conducted to ascertain whether the system produces the right results. Test data must be carefully prepared, results reviewed, and corrections made in the system. Unit testing, system testing and acceptance testing must be done in sequence
CONVERSION : Conversion is the process of changing from the old system to the new system. It answers the question, "Will the new system work under real conditions?" Four main conversion strategies can be employed: the parallel strategy, the direct cutover strategy, the pilot study strategy, and the phased approach strategy.PRODUCTION & MAINTENANCE: After the new system is installed and conversion is complete, the system is said to be production. During this stage, the system will be reviewed by both users and technical specialists to determine how well it has met its original objectives and to decide whether any revisions or modifications are in order. Changes to a production system to correct errors, meet new requirements, or improve processing efficiency are termed maintenance.