Every software has its life cycle. And each product goes through the stages of the life cycle differently. To be able to manage the process there are software life cycle methodologies.
A software development methodology is a system that defines the order of tasks, methods of evaluation, and control. There are many different models of such a process, each describing a different approach. And the model choice depends on the project area, budget, and timing of the final product.
The approach determines the success of the project because without a correctly chosen development methodology it is difficult to achieve stability and safety in the product work. Therefore, project managers try to find the best option. In this article, we will tell you about the most popular ones.
This software model appeared as one of the earliest in development. The basic idea is that the stages depend on each other. The next stage begins after the end of the previous one, thus forming a progressive movement forward. Teams from different stages do not communicate with each other and are responsible only for their phase.
In reality, the Waterfall model is not so easy. On the one hand, the development process is fast, with predetermined costs and timelines. But it is hard to imagine a project that would be realistic to execute strictly sequentially.
Therefore, the waterfall model is only suitable for projects with well-defined requirements and ways to implement them. Testing starts only after development is complete. So all errors are only visible at the end because of the strict sequence of actions. It is difficult to go back because it is not clear what to go back to. If a failure occurs at any stage, its consequences are only visible at the end.
The cost of making changes is high because you have to wait for the entire project to be completed. Subsequent changes will significantly increase the budget and delay the project release.
The V-model is an improved version of the waterfall model. It provides support in the planning and implementation of the project. And in the course of the project, the team sets different tasks. For example, it can be to minimize risks or to increase and guarantee quality. And also to reduce the overall cost of the project and improve the quality of communication between the project participants.
A feature of the model is the ability to verify and test a product that is in the initial design stages. Control of the process arises at each phase to make sure that it is possible to move to the next level. The testing phase takes place at the same time the corresponding stage of development, for example, during the coding phase unit tests are written.
V-model is convenient when there are clear requirements and smooth operation of the product is important.
RAD Model (Rapid Application Development Model)
RAD is an application development methodology. Several teams develop components or functions in parallel, like multiple mini-projects. So, in the first phase, basic functions are released, and subsequent cycles allow new additions to be added. The process will only end when the system is fully implemented. The customer is involved from the early stages to obtain feedback and make changes.
The RAD model includes business modeling, data modeling, process modeling, application build, testing, and deployment phases.
This is a good solution for small projects. As well as projects with clear requirements where additional features can be implemented. This approach reduces costs and minimizes development time. But if you need a large-scale system that requires a high level of planning, rigorous design, and adherence to developed protocols, then the model is not suitable.
RAD isn’t ideal for building complex computer programs, operating systems, or programs that contain a large amount of code.
In the incremental model, a project is designed, implemented, and tested with minor additions until the end of development. The underlying principle implies extending the capabilities, completing the modules and functions of the application. The development process itself is a sequence of versions, each of which is a complete and workable product.
Each iteration has its number, and the product has a version number after each iteration, e.g. v.1, v.2, etc. When one version is in operation, the next version, taking into account the shortcomings of the previous one, is only planned or already under development. This is how minor versions with improvements appear. These are the changes that do not affect the development core and are presented as sub-versions or releases.
The spiral model is similar to the incremental, but with an emphasis on risk analysis. All stages of the life cycle go in turns. It assumes 4 stages for each turn: planning; risk analysis; design; evaluation of the result, and transition to a new turn. This process reflects the essence of the name: going up, one goes through one spiral cycle to achieve the final result. And the same set of processes doesn’t need to repeat from turn to turn. But the results of each of them lead to the main goal.
In the spiral model, it is possible to add additional functionality to the software even in the late stages of development. Suitable for large and expensive projects. For example, to introduce new product lines and conduct research.
Program development in the iterative model can start with the requirements for only a part of the functionality, which can be subsequently supplemented and modified. That is, the project consists of parts and passes through the stages of the life cycle at each of them. Each stage is complete in itself, and their totality forms the final result. This approach allows to combat uncertainty and verify the correctness of technical or any other solution at early stages.
The model consists of four main phases: requirements definition and analysis, design and engineering, development and testing, evaluation, requirements revision, and suggestions for additions. The phases are repeated in each iteration.
Using an iterative model reduces the risk of failure and wasted budget and allows complete development at the end of any iteration.
Agile is a set of principles and ideas of agile development. In this model, all stages of the life cycle go through in one iteration, ready for any changes. At the beginning of each iteration, the team evaluates and analyzes the results, and plans the next iteration.
The advantage is that after each iteration, the customer can observe the result. However, due to the lack of a specific formulation of the results, it is difficult to estimate the labor and development costs.
The methodology goes with large, long-term projects with constantly changing requirements and adaptable to market conditions.
Agile includes Scrum and Kanban methodologies.
Scrum is a software development system. This approach divides the workflow into equal sprints. Before the sprint, the team formulates tasks. In the end, they discuss the results and begin a new sprint. The sprints are very easy to compare with each other, which makes it possible to manage performance.
Each person involved in the process has a role. There is a Scrum Team that works on the project. The Scrum Master is the person who organizes the work. And the customer himself is the Product Owner.
Kanban is a system that builds on the visualization of the team’s task process. The idea is to reduce the number of tasks in progress. The team performs tasks that are handed in individually. It goes through To do – In progress – Code review – In testing – Done. The task passes all stages on the board independently of the others. This approach allows to see the organization of the entire project and understand where the problem occurred.
At Techvice, we use Agile methodologies. Because of the ever-changing requirements based on user feedback, this model allows us to experiment and improve the product.
Development methodologies comparison
We talked about the main software development methodologies. It is impossible to say which one will be more suitable for your project, because not always the model you like will be the best option for its implementation. Opinion about the effectiveness of this or that methodology is often based on personal experience.