SDLC Models Explained: Agile, Waterfall, V-Shaped, Iterative, Spiral

Victor Osetskyi
Aug 29, 2017 · 4 min read

One of the basic notions of the software construction — is the Software Development Life Cycle model. Or simply SDLC models. SDLC — is a continuous process, which starts from the moment, when it’s made a decision to launch the project, and it ends at the moment of its full removal from the exploitation. There is no one single SDLC model. They are divided into main groups, each with its features and weaknesses.

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No matter what type of SDLC model chosen, each of them has basic stages.

Stage 1. Planning and requirement analysis

Each software development life cycle model starts with the analysis, in which the stakeholders of the process discuss the requirements for the final product. The goal of this stage is the detailed definition of the system requirements. Besides, it is needed to make sure that all the process participants have clearly understood the tasks and how every requirement is going to be implemented. Often, the discussion involves the QA specialists who can interfere with the process with additions even during the development stage if it is necessary.

Stage 2. Designing project architecture

In the second phase of the software development life cycle, the developers are actually designing the architecture. All the different technical questions that may appear on this stage are discussed by all the stakeholders, including the customer. Also, here are defined the technologies used in the project, team load, limitations, time frames, and budget. The most appropriate project decisions are made according to the defined requirements.

Stage 3. Development and programming

After the requirements approved, the process goes to the next stage — actual development. Programmers start here with the source code writing while keeping in mind previously defined requirements. The system administrators adjust the software environment, web programmers develop the user interface of the program and the logic for its interaction with the server.
The programming by itself assumes four stages

  • Algorithm development
  • Source code writing
  • Compilation
  • Testing and debugging

Stage 4. Testing

The testing phase includes the debugging process. All the code flaws missed during the software development are detected here, documented, and passed back to the developers to fix. The testing process repeats until all the critical issues are removed and software workflow is stable.

Stage 5. Deployment

When the program is finalized and has no critical issues — it is time to launch it for the end users. After the new program version release, the tech support team joins. This department provides user feedback; consults and supports users during the time of exploitation. Moreover, the update of selected components is included in this phase, to make sure, that the software is up-to-date and is invulnerable to a security breach.

SDLC MODELS

Evolving from the first and oldest “waterfall” SDLC model, their variety significantly expanded. The SDLC models diversity is predetermined by the wide number of product types — starting with a simple website to complex medical software. And if you take one of the SDLC models mentioned below as the basis — in any case, it should be adjusted to the features of the product, project, and company. The most used, popular and important SDLC models are given below:

During the years of the SDLC evolution, different models were developed from the basic cascade model to meet a huge variety of software development requirements and expectations.

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Read the full article about SDLC Models Explained: Agile, Waterfall, V-Shaped, Iterative, Spiral here.

So if you are already experienced in the SDLC models and you have your own professional opinion on this — leave your comments in the section below. If you have questions on picking up a correct model for your business — Contact Us, so we could assist you in this question. or visit our Services Page to learn more.

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Existek is a custom software development company helping our customers to solve their business challenges with best in its class software. Contact us to get an instant and free expert consultation about your custom software development project.

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