The systems development life cycle (SDLC) is a conceptual model used in project management that describes the stages involved in an information system development project, from an initial feasibility study through maintenance of the completed application.
Various SDLC methodologies have been developed to guide the processes involved, including the waterfall model (which was the original SDLC method); rapid application development (RAD); joint application development (JAD); the fountain model; the spiral model; build and fix; and synchronize-and-stabilize. Frequently, several models are combined into some sort of hybrid methodology. Documentation is crucial regardless of the type of model chosen or devised for any application, and is usually done in parallel with the development process. Some methods work better for specific types of projects, but in the final analysis, the most important factor for the success of a project may be how closely the particular plan was followed.
In general, an SDLC methodology follows the following steps:
- The existing system is evaluated. Deficiencies are identified. This can be done by interviewing users of the system and consulting with support personnel.
- The new system requirements are defined. In particular, the deficiencies in the existing system must be addressed with specific proposals for improvement.
- The proposed system is designed. Plans are laid out concerning the physical construction, hardware, operating systems, programming, communications, and security issues.
- The new system is developed. The new components and programs must be obtained and installed. Users of the system must be trained in its use, and all aspects of performance must be tested. If necessary, adjustments must be made at this stage.
- The system is put into use. This can be done in various ways. The new system can phased in, according to application or location, and the old system gradually replaced. In some cases, it may be more cost-effective to shut down the old system and implement the new system all at once.
- Once the new system is up and running for a while, it should be exhaustively evaluated. Maintenance must be kept up rigorously at all times. Users of the system should be kept up-to-date concerning the latest modifications and procedures.
Stages in system development life cycle
What is Analysis?
The analysis stage is done by a system analysis before building a programme. In this stage the analysis should have to check all the customer requirements that need to develop the required software system. Before starting that process analysis must gather each and every requirements about that product
What is System Design?
This is the most crucial part in the development of a system based on the user requirements and the details of analysis the new system must be designed. The logical system design arrived at as a result of system analysis and is converted into physical system by designer.
What is Implementation?
In this stage physical system specifications are converted into a working and reliable solution. This is where the system is developed. It is followed by testing and then implementation.
What is Testing?
This is a one of most important stage in SDLC. The testing activities are mostly done in this stage. The testing is done in all aspects of the system and also tested in functionality and performance.
What is Maintenance?
Maintenance is includes all the activities after the installation of software. Removing errors is one of the activities of maintenance.
Examples for Software Process Models
- Waterfall model
- Spiral model
- RAD model (Rapid Application Model)
- Extended waterfall model
- Evolutionary development model