Software Development Lifecycle (SDLC) Models

Software Development Lifecycle (SDLC) Models

What is Software Development Lifecycle (SDLC) :

The software 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/product.

1. Understand the relationship between development, test activities and work products in the Development life cycle and give examples based on project and product characteristics and context.
2. Recognize the fact that software development models must be adapted to the context of project and product characteristics.
3. Recall reasons for different levels of testing and characteristics of good testing in any life cycle model.

The development process adopted for a project will depend on the project aims and goals. There are numerous development life cycles that have been developed in order to achieve different required objectives. These life cycles range from lightweight and fast methodologies, where time to market is of the essence, through to fully controlled and documented methodologies where quality and reliability are key drivers. Each of these methodologies has its place in modern software development and the most appropriate development process should be applied to each project.

The models specify the various stages of the process and the order in which they are carried out. The life cycle model that is adopted for a project will have a big impact on the testing that is carried out. Testing does not exist in isolation; test activities are highly related to software development activities. It will define the what, where, and when of our planned testing, influence regression testing, and largely determine which test techniques to use. The way testing is organized must fit the development life cycle or it will fail to deliver its benefit. If time to market is the key driver, then the testing must be fast and efficient. If a fully documented software development life cycle, with an audit trail of evidence, is required, the testing must be fully documented. 

Verification

Confirmation by examination and through the provision of objective evidence that specified requirements have been fulfilled.

Validation

Confirmation by examination and through provision of objective evidence that the requirements for a specific intended use or application have been fulfilled.

V-model

A framework to describe the software development life cycle activities from requirements specification to maintenance. The V-model illustrates how testing activities can be integrated into each phase of the software development life cycle.

In every development life cycle, a part of testing is focused on verification testing and a part is focused on validation testing. Verification is concerned with evaluating a work product, component or system to determine whether it meets the requirements set. In fact, verification focuses on the question 'Is the deliverable built according to the specification?'. Validation is concerned with evaluating a work product, component or system to determine whether it meets the user needs and requirements. Validation focuses on the question 'Is the deliverable fit for purpose, e.g. does it provide a solution to the problem?'.

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Types of Software Development Models:

• V Model
• Waterfall Model
• Iterative Lifecycles
• Rapid Application Development
• Agile Process
• Spiral Model

Check about Waterfall model and V-Model in SDLC (Software Development Lifecycle)