Waterfall model of software development

One of the most famous and widely used software development processes is the Waterfall model. The Waterfall model is a sequential software development process. It was derived from the manufacturing industry. One can see a highly structured flow of processes that run in one direction. At the time of its creation, there were no other software development methodologies, and the only thing the developers could have imagined was the production line process that was simple to adapt for software development.

The following diagram illustrates the Waterfall model of software development:

Waterfall model

The Waterfall approach is simple to understand, as the steps involved are similar to that of the SDLC.

First, there is a requirement analysis phase, which is followed by the designing phase. There is a considerable time spent on the analysis and the designing part. And once it's over, there are no further additions or deletions. In short, once the development begins, there is no modification allowed in the design.

Then comes the implementation phase, where the actual development takes place. The development cycle can range from three months to six months. During this time, the testing team is usually free. When the development cycle is completed, a whole week's time is planned for performing the integration of the source code. During this time, many integration issues pop up and are fixed immediately. This stage is followed by the testing phase.

When the testing starts, it goes on for another three months or more, depending on the software solution. After the testing completes successfully, the source code is then deployed in the production environment. For this, a day or so is again planned to carry out the deployment in production. There is a possibility that some deployment issues may pop up. When the software solution goes live, teams get feedback and may also anticipate issues.

The last phase is the maintenance phase. Feedback from the users/customers is analyzed, and the whole cycle of developing, testing, and releasing new features and fixes in the form of patches or upgrades repeats.

There is no doubt that the Waterfall model worked remarkably for decades. However, flaws did exist, but they were simply ignored for a long time. Since, way back then software projects had ample time and resources to get the job done.

However, looking at the way software technologies have changed over the past few years, we can easily say that the Waterfall model won't suit the requirements of the current world.

Disadvantages of the Waterfall model

The following are some of the disadvantages of the Waterfall model:

• Working software is produced only at the end of the SDLC, which lasts for a year or so in most cases.
• There is a huge amount of uncertainty.
• It is not suitable for projects where the demand for new features is too frequent. For example, e-commerce projects.
• Integration is performed only after the entire development phase is complete. As a result, integration issues are found at a much later stage and in large quantities.
• There is no backward traceability.
• It's difficult to measure progress within stages.

Advantages of the Waterfall model

By looking at the disadvantages of the Waterfall model, we can say that it's mostly suitable for projects where:

• The requirements are well documented and fixed.
• There is enough funding available to maintain a management team, a testing team, a development team, a build and release team, a deployment team, and so on.
• The technology is fixed, and not dynamic.
• There are no ambiguous requirements. And most importantly, they don't pop up during any other phase apart from the requirement analysis phase.