What Is SDLC? 7 Phases of System Development Life Cycle
Which is the most important phase in the systems development process? Although all seven phases of SDLC are critical, the most important one is widely considered to be the feasibility or requirements of the analysis stage, because this is when the project team receives the customer’s requirements and starts developing the product according to those needs.
What is SDLC?
The most widely used definition of the system development life cycle would be the following: it is a methodical model used for the efficient development of high-quality software. The model includes steps to develop, implement, maintain, and upgrade a particular software system. The ultimate goalof SDLC is to help teams develop a high-end product according to the stakeholder’s needs within an established timeframe. Despite being simple and straightforward, the model serves as a reliable tool for global development teams that stick to excellence and, if implemented thoughtfully, will serve as a step-by-step guide for digitally agile software development vendors. It contains several common methodologies that are customer-tailored for each specific project, and, if correctly chosen, can further aid the teams during each stage of the SDLC.
The 7 Phases of SDLC
Each stage of the software development life cycle should involve a variety of tech talents since it takes a lot of technical expertise to move from one step into another without delays and shortcomings. Many customers these days choose a dedicated team of software developers as a safe, flexible, and cost-efficient option suitable for various small and large-scale projects. Long story short, these are the seven fundamental system development life cycle phases:
- System analysis and requirements;
- Design and prototyping;
- Integration and testing;
Regardless of which software development methodology is chosen, they follow the basic stages creating any digital product. Now, let’s talk about each phase in more detail.
The planning stage is the first step in software development. Before getting down to business, it is crucial to create a well-thought-out strategy for the upcoming work. During this stage, developers usually analyze the core challenges of the project and dive deeper into the problem the software is intended to pinpoint. The ultimate goal of this stage is to come up with an idea of how the final software will help address a specific problem. Engineers and other team members are involved in discussing the technologies that will be used in the project, the workload of the team, the limitations, the time frame, and the budget. The customer’s requirements help to determine the best design solutions for the software.
System Analysis and Requirements
The purpose of this stage is to determine the detailed requirements for the future software since it is important to make sure that all team members understand the assignment and are ready to implement each of the stakeholder’s requirements in practice. QA experts are also involved in the discussion, meaning that they can set their own requirements and, if necessary, adjust the process. Depending on the selected development model, approaches to determining the moment of transition from one stage to another may vary. For example, in the cascade or V-model, the system analysis and requirements phase are fixed in the SRS document, the design of which should be completed before moving to the next stage.
Design and Prototyping
The design stage creates a basis for the development step and can relatively decrease the time spent on the following stages of SDLC. The team works together to outline:
- the system interface;
- main software features;
- network requirements.
A software requirements specification (SRS) document that was created during the early stages is typically complemented with more detailed data and structure that will later be utilized during development. The very first prototype of the software is constructed to help the team get a general idea of what the result should look like.
After all the product requirements are approved, the team can finally move to the development itself. At this phase, the developers start writing the program code in accordance with the previously defined needs. System administrators configure the software environment, while front-end developers build the user interface of the software along with the logic of its interaction with the server. They also write unit tests, conduct a review of the written code, create builds, and deploy the finished software in the software environment. This cycle is repeated until all requirements are fulfilled.
The development stage implies four core steps:
- Algorithm development (creating the logic of the software’s operation);
- Writing the source code;
- Compilation — conversion into machine code;
- Testing and debugging — (mainly unit testing).
Integration and Testing
Once the software is built, it’s time to put it to the test to understand what can go wrong when real users come into play. This step in the software development life cycle requires the team to check if they got what they initially wanted. At this stage, the team must check for defects and deficiencies. Later, after discovery, the experts try to resolve all issues until the product meets current specifications. This stage is crucial because it would be naive to think that all features would work correctly straight away. QA testers should cooperate with engineers as the latter sometimes don’t have enough knowledge of software testing tools and strategies.
As soon as the testing stage is over, it’s high time to integrate the information system into the environment, install it, and present the outcome to the end user. “Let’s start using what we’ve got.” This step includes feedback from end users. Depending on their feedback, the developers need to make changes and adjustments. Usually, this part of the SDLC process happens in a limited way at first. Occasionally, as required, a product may be released in a specific market prior to final launch.
The operation and maintenance phase includes all activities to ensure the effective functioning of software systems once it reaches the market and finally meets its end users, including fixing errors discovered during the testing phase, finding their reasons and eliminating them, improving the system’s operational characteristics, adapting the system to the environment, and, if necessary, more significant work on enhancing the system. The team dedicates its time and resources to helping the system evolve. In some cases, this phase can be the most expensive during the software development life cycle.
These are the main stages of software development. Each stage is a set of activities that help teams create a final software product. Depending on the selected software development model, they can change, go through cycles, or be flexible.
Basic SDLC Methodologies
Although the SDLC model is self-sufficient in and of itself, there are several more narrowed-down approaches that would help in moving software development forward. Here is a list of the most common ones:
The Waterfall Model
The waterfall model is one of the earlier approaches to SDLC, and it adopts a linear, sequential approach, meaning that the team has to fully complete one phase before starting another one. All the stages are interconnected but have different project plans. The outcome of the previous stage works as a foundation for the next one. This approach can be a good choice for small projects with clear and well-documented requirements and sufficient resources supported by the required expertise.
One of the most important advantages of the waterfall model is simplicity — a team cannot go forward if the work on the previous stage is not completed. Thanks to that, it is simple to control and manage since each stage has a particular deadline and deliverables. However, the methodology would not work on long and more complex projects with high levels of uncertainty and changing requirements. As soon as the software is in the testing stage, it is almost impossible to go back and change some features that were not initially thought over.
The Spiral Model
The spiral model is basically a waterfall model with a great focus on risk analysis. It enables developers to pass the project through spirals repeatedly, ensuring better testing and risk evaluation. The model is divided into four key stages: identification; design; construction or building; and evaluation and risk analysis. The core advantage of this model is that it enables a gradual approach to product development and refinement. It will be a perfect fit for medium-risk projects where the initial requirements have either changed drastically or the product needs to be changed significantly. Both the team and the customer should be aware, though, that the end deadline may be unknown due to the repeated circulation over the four stages.
The V-model, or Verification and Validation model, is somewhat like the waterfall model, and it requires a defined timeline because the testing stage is incorporated into each step of product development. The development cycle goes hand-in-hand with the testing one. Such a methodology would be suitable for small projects with clearly defined objectives and requirements. Plus, it is relatively easy to manage because each stage has clearly defined deliverables. But it has several drawbacks too: it is not useful for projects with a high risk of changing requirements, as well as overly complex and long projects.
The Iterative Model
The fundamental idea of iterative development is the following: instead of one long sequence of actions, the entire product life cycle is divided into several minicycles (iterations). In each of the iterations, a single component of the system is developed, altered, or improved, after which it is added to the previously developed functionality. Mini cycles are repeated a couple of times, and the result of each is an updated version of the product, which in turn undergoes testing with users. In order to test the result, the product does not have to be completely ready. Just implementing the basic functionality would be enough. This methodology is an effective approach to product development with many uncertainties. If a team intends to dynamically develop the project, constantly improve the functionality, and adapt it to the needs of users, then this is a viable alternative to the traditional waterfall model.
The Big Bang Model
This methodology is mostly used for small and experimental projects, and when the stakeholders don’t have a clear vision of what the software should look like. The team of engineers is working on various system variations, which helps the client decide on the one that best fits their needs. The Big Bang model doesn’t require a lot of planning — the team conducts a requirements analysis and carries out the development and design processes based on its understanding. This model is applicable only for small projects due to the high risk and uncertainty.
The Agile Model
This methodology saves developers the risk of spending months or even years on a process that ends up failing because of a small mistake at an early stage. Instead, the team members are expected to work directly with customers to understand the software goals and suggest solutions in a fast and streamlined way. While the team is focused on delivering consistent product functionality at each iteration, there is an opportunity to continually improve and redistribute the overall backlog of the product. New or changed backlog items can be scheduled for the next iteration, allowing for changes to be made over several weeks.
Benefits of Software Development Life Cycle
The SDLC framework exists to help businesses reduce time to market, deliver better performance, save money, and increase the potential value of their product. The SDLC is especially helpful in software development because it forces development teams to work within strict limits. In other words, to ensure the right action at the right time and for the right reasons, the SDLC will force developers to follow every step they need to take.
The model can be viewed as a blueprint for success; following it blindly doesn’t necessarily guarantee success, but it increases the likelihood that the customer will be happy with the results. Software development is a broad topic, and it can cover everything from web design tools and online forms to more robust machine learning or back-end systems. Whether your team is involved in writing code in the browser or doing more robust development, they need a roadmap.
Long story short, these are the core benefits of implementing a SDLC model:
- A clear understanding of the stakeholder’s requirements;
- The ability to track the progress at each stage of the SDLC;
- Detailed software testing;
- Close collaboration among the team members;
- Defined timeline for the product delivery;
- Team members’ flexibility.
Importance of 7 Phases of System Development Life Cycle
We’ve already explained why the SDLC model is crucial — it serves as a blueprint for teams and helps them create state-of-the-art software that will be of great use to multiple consumers. After all the details like the customer’s requirements, the scope of the project, and the budget are determined, it’s important to come up with a system that will be of great use for both the team and the customer. Otherwise, the outcome will not satisfy the customer and can even damage the reputation of the software development vendor. The project’s scope and complexity are the primary factors that help select the SDLC model and begin the software development process.
Which Is the Most Important Phase in the System’s Development Process?
It’s hard to single out one stage that is the most important since all seven are fundamentally interconnected and each stage feeds into the next one. The SDLC model cannot function without one of its core elements because it will lead to poor-quality software, low customer satisfaction, and a loss of money. However, if we had to choose a single most important stage, it would be system analysis and requirements. It functions as a guideline for all the following steps, helps the team become fully aware of the initial requirements, and meet or even exceed the customer’s expectations.
Successful and responsive software takes months to develop, but it can take a lot more time if all seven stages of the SDLC have not been executed correctly. Although the stages may vary in each specific project, the logic behind the model remains the same. Conversely, if a team understands the importance of each phase and dedicates all its resources to carefully planning, analyzing, designing, developing, implementing, and maintaining its creation, the software product is likely to exceed any expectations and meet the customer’s goals. It goes without saying that the mere ability to follow all seven stages will not guarantee success, but it will make the process easier, address potential shortcomings, and build a positive reputation both for the team and the software development services provider.