8 Software Development Models: Detailed Guide 2021
In the article, you’ll get to know the 8 software development models, their structures, advantages, and disadvantages so that to have a greater ability to manage projects by combining best practices.
Before launching a project, you have various options of software development models to choose from. Do you need to split the work into several independent parts, and allocate a separate team for each of them? Or is it worth working in short iterations so that you can track your performance and make changes in time? Or is it better to plan all the stages in advance and do everything step by step? We will help you determine the best solution out of many.
- Software development models
- Waterfall model
- V model
- Incremental model
- RUP model
- Agile model
- Iterative model
- Spiral model
- Prototype model
- FAQ: Models of the System Development Life Cycle
Software development models
The software product has its own life cycle, which includes the stages from the idea identification till its implementation in the code and subsequent support. It is so-called navigation through the complex process of creating software.
The choice of Software Development Life Cycle (SDLC) depends on the specifics of the project, the budget, business preferences, timeline, and even the temperament of the manager. In fact, now there are over 50 software development models. Each of them has its own peculiarities and benefits as well as minuses. We’ll cover the 8 popular ones and dive deep into their essence.
Within the waterfall model, the engineering team strict-sequentially moves from one stage to another. The transition to a new phase is possible only after the completion of the previous one.
To illustrate, first, the stage of the requirements’ analysis is carried out. When it is completed, the process results in the design phase. After its full definition, a transition to the development phase takes place. And in such a manner, the next stages of testing, deployment, maintenance are worked out as well.
Due to such a strict process, the cost and the timeline of the software development are predetermined, and the entire process goes fast. However, this is a double-edged approach, since the waterfall model prevents you from taking steps back and you cannot be sure of the quality of the product until its development is complete. That is to say, if something does not fall into the plan requirements, then it most likely will not be implemented within the agreed budget and terms.
It turns out the waterfall model will give excellent results in projects with clear and pre-defined requirements and ways to implement them. We recommend using it in next cases:
- projects with known and fixed demands, for which there would be no changes in the development process;
- when a product migrates from one platform to another. That is to say, the requirements remain the same, only the system environment or programming language changes;
- projects where a pre-defined budget and timeline is required;
- when you are sure about all the tech stack and tools you need (still, preferably for small or mid-sized projects).
V-model (“Step by step” or validation and verification)
The V-model is focused on checking and testing a product from the first stages of development. While developers write the code, testers write unit tests. In other words, the testing part is carried out in parallel with development. If errors are found – they are at once eliminated, and only then a new phase of work starts. Thus, this approach is useful if uninterrupted and high reliable product functionality is critical to you.
We advise you to use this software development model when in advance you get available the methods of solving functional problems, the tech stack for their implementation and the talents with the necessary experience. Like the waterfall model, the V-shaped one works best when all requirements’ information is available in advance as well.
Within the incremental model, the software development process is divided into separate modules, which are performed in a linear sequence, but in several increments (versions). Consequently, the improvement of the product is planned all the time until the SDLC is completed.
The model like others has its pros and cons. Among the advantages, we can underline the next:
- the opportunity for the client to give feedback regarding each finished part and control how much work has been done;
- costs, reanalysis, and documentation set are significantly reduced if compared to a waterfall model;
- such an approach allows you to work out the risks and bring the basic version of the product to the market, when all the planned functionality may still be at the design stage.
The major cons are:
- if there are constant changes, the structure of the system can be violated;
- the need for a complete functional definition of the system at the beginning of the life cycle to ensure the definition of increments and project management;
- the deadlines for the delivery of the system can be delayed due to limited resources (talents, finances).
Rational Unified Process (RUP) model
A RUP model is an iterative process, which is carried out in several short-term iterations. Usually, the development lasts from 2 to 6 weeks. The model allows you to quickly respond to changing requirements, detect and eliminate risks at the early stages, and effectively control the quality of the product.
The peculiarity of the methodology is that the degree of formalization can vary depending on the needs of the project. You can create all the required documents and reach the maximum level of formalization at the end of each iteration, or when you need them for work, up to their complete absence.
RUP can be effective both in small projects, where you can reduce execution time and costs, and in large and complex ones, where a high level of formalism is required, for example, for the purpose of further certification of a product. This advantage makes it possible to use the same development team to implement different scope requirements.
Agile is a group of methodologies that strive to improve the product through repetitive work cycles and continuous customer feedback. The major project management methodologies include Scrum and Kanban.
Within the Scrum process, the team is led by the Scrum Master. Work is divided into short, repetitive cycles called sprints. Developers gradually add functionality to the system and deliver working code to the client at regular intervals. That enables minimizing project risks and increasing ROI.
In the case of Kanban, teams visualize tasks using a whiteboard or special online tools. Tasks move between columns indicating their status. This approach allows you to effectively prioritize, monitor the progress of the project, and limit the amount of work in progress.
Due to Agile flexibility and the maximum transparency of work processes, the model is highly popular in use. According to the State of Agile study (2020), 95% of respondents said that their companies partially or completely use Agile.
In the iterative model, the process of development doesn’t start with a complete specification of requirements. Instead, the team first implements a small set of software demands, which is then analyzed to determine further steps. Each iteration introduces design changes and new functionality.
The main idea behind this method is to design a system gradually and with repetitive loops. Thus, the team iteratively expands developing versions until the complete system is implemented.
The minus is that you can’t initially set the budget and terms for the implementation of the final version, since requirements are formed in the course of development and the total amount of work is not determined.
As the model name suggests, SDLC spins in a spiral and is divided into phases. They are planning, analysis and identification of risks, development, and testing. After each cycle, the team introduces a certain ready-made functional, assesses the result, and moves to a new round.
The spiral model uses two approaches of the waterfall and prototyping. However, compared to the Waterfall model, spiral development is quite flexible. For example, it is acceptable to return to the previous phase and revise the decisions made there. And only then move on. Thus, the spiral model can be useful if the customer cannot provide a sufficiently clear list of requirements for the final product, or in case significant changes are expected within the development.
Using the prototyping model allows you to create a working software component that implements individual functions already at the requirements’ phase. You can work with this prototype, determine its strengths and weaknesses, and report the results to the developers. This feedback helps to change and adjust the specification of requirements for a software product. As a result of this work, the project will reflect the real needs of users.
The prototyping model is recommended when:
- there is not fully set of requirements for the software product or they can be refined during the development process;
- there is the need for temporary demonstrations of the functionality;
- the developers are not sure about the chosen solutions regarding the user interface and functionality, the applied architecture or algorithm.
We introduced you to the basic software development models. However, the option you might like from the description is not always the best for the implementation of your particular project. To take advantage of partnering with an experienced development team will help you in your final choice.
At FreySoft it is within our power to find a solution that will allow you to build your project as efficiently as possible and ultimately bring the product to market. Besides our flexible engagement models, we offer our customers particular services and expertise including custom software development, PWA & native app development, AI & Machine learning solutions, UI/ UX design, quality control, security testing, technology and technical advice.
We’ve mastered a wide range of industries with the strongest track record in such domains as Fintech (find more about our recent Fintech project of switching from the monolith to microservices), e-commerce, automotive, hospitality & travel, security, healthcare.
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FAQ: Models of the System Development Life Cycle
The software engineering model is a structure of life process of any system or software product from identifying conception of an idea to the deployment. The model determines the sequence of execution and the relationship of processes, actions, and tasks throughout the life cycle. It can include the various amount of stages depending on the scope, size, complexity, and budget of the project.
The 7 main stages of SDLC are the idea identification, requirements’ analysis, system design (architecture), development phase, testing, deployment, and support. Each stage influences the actions in the subsequent ones and provides promising indications for the future of the product.
There is no best-fit solution for all software development. Project managers define different tasks and milestones in a product, and they organize them based on a variety of factors. You as a client and your engineering team mutually discuss the scope, size, and complexity of the future product. Further, based on the outcomes and business needs, you approve the solution of the best software development model.
The Waterfall is the oldest of all software development models. Winston Walker Royce first presented it in 1970. Since then, it has become widespread, especially in the software industry. It is best suited for short and uncomplicated projects with clearly defined requirements.