Waterfall Model

In the waterfall model (also known as the classical life cycle model), the development of software proceeds linearly and sequentially from requirement analysis to design, coding, testing, integration, implementation, and maintenance. Thus, this model is also known as the linear sequential model. This model is simple to understand and represents easy-to-manage and measure processes. The waterfall model comprises different phases and each phase has its distinct goal. These phases are given below:

Requirement Analysis: This focuses on the requirements of the software which is to be developed. It determines the processes that are incorporated during the development of software. This phase involves interaction between the user and the software engineer and produces a document known as a software requirement specification (SRS).

Design: This determines the detailed process of developing software after analyzing the requirements. In this phase, the emphasis is on finding a solution to the problems defined in the requirement analysis phase. The software engineer is mainly concerned with the data structure, algorithmic detail, and interface representations.

Coding: This emphasizes the translation of design into a programming language using the coding style and guidelines. The program created should be easy to read and understand. All the programs are written are documented according to the specification.

Testing: This ensures that the product is developed according to the requirements of the user. Testing is performed to verify that the product is functioning efficiently, and with minimum errors. Note that testing is a multi-stage activity, which emphasizes verification and validation of the product.

Maintenance: This delivers fully functioning operational software to the user. Once the software is accepted and deployed at the user's end, various changes occur due to changes in the external environment. The changes also occur due to changing requirements of the user and changes occurring in the field of technology. This phase focuses o modifying software, correcting errors, and improving the performance of the software.