Software Development Lifecycle (SDLC) Models

Outline of software development models

SDLCs are meant to present an outline of software development teams can cling to. These lifecycles can be distinguished by their way of dealing with the different activities in the evolution of the software as well as their way of handling problems that arise during such a development. There are two types of models: those that go through each of the activities sequentially only once and those that go through each of the phases many times. Those that execute the stages in a lifecycle iteratively produce different artifacts (such as prototypes as well as documents) after each iteration. The major benefit is that even if the whole project is cancelled there are pieces left that could be used in further projects or developments.

Be aware that there is no one best practice for every development process. The following is just supposed to list the most common ways of managing software development processes. Depending on the company structure, complexity of the project, customer requirements and team size as well as knowledge in and usage of tools each of these models has advantages and disadvantages.

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:

1. Requirements Analysis: The system requirements are defined. In particular, the deficiencies in the existing system must be addressed with specific proposals for improvement. This can be done by interviewing users of the system and consulting with support personnel.

2. Design: The proposed system is designed. Plans are laid out concerning the physical construction, hardware, operating systems, programming, communications, and security issues.

3. Construction: 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.

4. Integration & Functional Testing: 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.

5. Acceptance: 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.

There are various approaches to managing project activities including agile, interactive, incremental, and phased approaches.

Regardless of the approach employed, careful consideration needs to be given to clarify surrounding project objectives, goals, and importantly, the roles and responsibilities of all participants and stakeholders.