SOFTWARE DEVELOPMENT LIFE CYCLE

SOFTWARE
Software development is the process of developing software through successive phases in an orderly way. It is a complicated process as it requires careful planning and execution to meet the goals. Different phases in this development process include, the actual writing of code, preparation of requirements and objectives, the design of what is to be coded, and confirmation that what is developed has met objectives. Before systems development methods came into existence, the development of new systems or products was often carried out by using the experience and intuition of management and technical personnel. However, the complexity of modern systems and computer products long ago made the need clear for some kind of orderly development process.

The different phases involved in Software Development are as follows:
1.Identification of required software
2.Analysis of the software requirements
3.Detail specification of software requirements
4.Software Design
5.Programming
6.Testing
7.Maintenance


DEVELOPMENT PROCESS
The software development process is guided by some systematic software development method (SDM). Also referred by a number of terms, like process models, development guidelines, and systems development life cycle models (SDLC). All these Software Development methods generally include the following development phases:

• The existing system is evaluated and its drawbacks identified, usually through interaction with system users and support personnel.
• The new system requirements are defined, the drawbacks in the existing system are addressed with specific proposals for improvement.
• The proposed system is designed and plans are laid out concerning the physical construction, hardware, operating systems, programming, communications, and security issues.
• The new system is developed and the new components and programs are obtained and installed. Users of the system must be trained in its use and all aspects of performance is tested. If necessary, adjustments are made at this stage.
• The system is put into use. This can be done in different ways. The new system can phase 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 is exhaustively evaluated. Maintenance is kept up rigorously at all times. Users of the system are kept up-to-date concerning the latest modifications and procedures.

Systems Development Life Cycle Model

The Systems Development Life Cycle model was developed as a structured approach to information system development that guides all the processes involved from an initial feasibility study through to maintenance of the finished application. SDLC models take a variety of approaches to development. Some of these life cycle models include:

1. WATERFALL MODEL

2. V-SHAPE MODEL

3. SPIRAL MODEL

4. INCREMENTAL MODEL

5. PROTOTYPE MODEL

6. RAD MODEL

7. AGILE MODEL

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