What’s the SDLC? – Explaining the Software Development Lifecycle

Managing the development of software can be hard because requirements change, technology moves forward, and different teams need to work together. The software development lifecycle (also known as the technique provides a structured management framework with clear goals for each step of the software development process. This helps solve these problems.

This method includes detailed rules for making, expanding, and running the software system. The SDLC makes a detailed plan with different stages, each with its steps and results. Following the SDLC makes development go faster and reduces the dangers and expenses that could come up with other production methods.

This article gives companies that want to use SDLC-based software development a complete guide. We will explain how SDLC strategies work by detailing each typical product lifecycle phase.

What's the Software Development Life Cycle?

The Software Development Life Cycle, also known as the SDLC, is a way to make high-quality software while spending as little money and time as possible. SDLC is a series of steps that help organisations quickly make thoroughly tested software ready to be used in the real world.

SDLC has six different phases, which are explained above. Well-known SDLC methods include the spiral model, the traditional waterfall model, as well as the one known as Agile.

So, what is the Software Development Life Cycle's working mechanism?

How the SDLC Works

The software development life cycle is a plan for each stage of making software. It breaks the process into different phases, each of which has its own:

• Anticipations.
• Activities.
• Outputs.
• Procedural guidance.
• Key individuals.
• Objectives.
• Written records.

How many steps there are and what they are will depend on the company and its goals for the product. Most businesses define SDLCs as having five to seven phases, but more complicated projects can have ten or more phases.

At the end of each step in an SDLC, there is a document, a diagram, a piece of working software, and so forth that is used as the input for the next phase. Even though this approach looks like a funnel, modern SDLC methods are only sometimes linear. In the SDLC, the team frequently takes back one or two steps to fix or improve things.

The SDLC for a product needs to be an ongoing procedure that the group updates or at least looks over often. Business experts, developers, QA staff, and stakeholders must work together to keep an SDLC current.

Since the 1960s, SDLC methods have been around, and most of their main ideas have changed. The testing phase was when the most important change happened. Testing was a separate Software Development Life Cycle (SDLC) step. Still, teams now prefer to work on security throughout the SDLC to make more reliable, secure-by-design software.

Phases and Best Practises

If you follow SDLC's best practices and stages, the process will go smoothly, quickly, and effectively.

Plan

Tasks like cost-benefit assessment, scheduling, estimating and allocating resources are often done during the planning phase. To make a software specification document, the development team gets requirements from customers, experts inside and outside the company, and managers.

The document lays out what is expected and the common goals, which helps with planning the project. The team figures out how much it will cost, makes a schedule, and comes up with a detailed plan for how to reach their goals.

Design

"How will we be able to get what we want?" At the beginning of this phase of the SDLC, the software requirements are turned into a plan of design called the Design specifications. Then, everyone interested in this plan looks it over and gives feedback and ideas. 

Having a plan for getting stakeholder feedback and putting it into this document is important. If the project fails at this stage, the costs will increase and, at worst, the whole thing will fall apart.

Implement

During the execution phase, the team that made the product writes the code for it. They look at the need to find smaller programming duties they can do daily to achieve the end result.

Build

At this point, the real building begins. Every developer needs to follow the plan that was made. Also, check that you have clear rules about the code's style and how it should be used.

For example, you could define a naming style for files or a naming style for variables, such as camelCase. This makes it less difficult for everyone on the team to create code in the next stage that is clear and easy to test.

Test

The development team checks for bugs in the software both automatically and by hand. As part of quality analysis, the software is tested for bugs to see if it meets customers' demands. Since many teams test every line of code they write as soon as they write it, the testing phase is often done at the same time as the development phase.

Software Deployment

At this point, the objective is to move the programme into the manufacturing setting so users can begin employing the product. However, many organisations opt to route the product into various deployment environments, such as testing or organising environments.

This allows everyone to try the product before it goes on the market. Also, any last mistakes can be found and fixed before the product is released.

The Evolution of Security's Role in the Software Development Life Cycle (SDLC)

Initially conceived, the Software Development Life Cycle (SDLC) treated security measures as a subsidiary component, relegated mainly to the testing stage. This approach led to numerous vulnerabilities either being detected too late or remaining undetected altogether.

The Paradigm Shift to Embedded Security

In contemporary times, it is universally acknowledged that security cannot be an afterthought in SDLC. Embedding security practices at every stage is paramount for creating robust software applications. By proactively identifying and rectifying vulnerabilities at the outset, not only is the software fortified, but time and financial resources required for rectifications at later stages are also minimised.

Principles of a Secure SDLC

The concept of "Secure SDLC" has gained considerable traction in today's software industry. In line with this paradigm, various security assurance techniques must be integrated throughout the development life cycle. This includes, but is not limited to, penetration testing, threat modelling, code reviews, and architecture assessments.

The Advantages of a Security-First Approach in SDLC

The merits of adopting a Secure SDLC model are manifold:

• Cost-Effectiveness: Early detection and rectification of vulnerabilities lead to decreased expenses in the long run.
• Enhanced Awareness: Key stakeholders are kept well-informed of security issues, thus enabling more educated decisions.
• Risk Mitigation: With a security-integrated approach, the overall business risk to the organisation is substantially reduced.
• Increased Software Integrity: A security-centric SDLC results in inherently safer software.
• Early Discovery of System Flaws: Security mechanisms enable the timely identification of potential system weaknesses.

Integrating security measures throughout all stages of the Software Development Life Cycle is not just best practice—it is essential for modern software development. With advancements in security testing tools, making SDLC secure has become more accessible than ever.

What Are the SDLC Models?

A software creation lifecycle model shows how SDLC works in a structured way to help organisations put it into practice. Different models put the SDLC phases in a different order to optimise the development cycle. Here, we look at a few typical SDLC models.

Waterfall

The waterfall model is the most basic and simplest SDLC model available. The stages of a waterfall happen in order, and each stage relies directly on how the one before it turned out. In an actual waterfall model, the group never steps back a step after completing a phase. This means the model's success depends on how well the team can avoid making mistakes.

Iterative

The iterative process says that teams should start making software with just a small subset of demands. Then, they keep improving versions as time passes until the whole software is ready to be made. The team makes a new software version at the end of each round.

V-Shaped Model

In a V-shaped model, the phases of verification and validation happen at the same time. A phase of validation follows each phase of testing. The model runs in a V-shape, with every stage of development followed by a testing phase.

Spiral

For risk analysis, the spiral model mixes the iterative model's small cycles with the waterfall model's linear flow. By making prototypes at each phase, you can use the spiral framework to ensure software is slowly released and improved.

Prototype Model

In the prototype model, the team has to make a working model of the product during the normal design phase. Companies choose this model because it lets them get valuable customer feedback early on. Users give feedback on the prototype, programmers make the changes that users ask for, and the team makes an improved prototype model.

This process keeps going until customers have no more negative feedback. After that, the group gets a customer-focused requirements assessment and makes the final product.

Agile

The phases of the SDLC are broken up into several phases of development by the agile model. The team moves quickly through the phases, making only small changes to the software in each cycle. They keep looking at requirements, strategies, and outcomes to act quickly when things change. The agile model works better than others because it is both incremental and incremental.

Big Bang Model

The Big Bang model is a risky SDLC type that puts most of its resources into development without doing a thorough evaluation at the beginning of the cycle.

A big bang begins with a little planning and moves quickly to the coding stage. Most of the time, developers are the sole individuals who figure out what needs to be done, write the code, and make sure the code works.

Which SDLC model works best and is used most often?

Each SDLC model gives your team a different way to handle project challenges. The details of the project and the desired results have a big impact on what model to use. For instance, the waterfall model is best for projects where your team needs more customer access and can only sometimes get feedback from them. 

However, the flexibility of the Agile model makes it better for lengthy endeavours with requirements that constantly change.

Because of this, the Agile SDLC framework is becoming more popular and in demand. This need is mostly due to how flexible and based on core principles the agile model is. By "core principles," we mean things like adaptability, customer engagement, lean growth, teamwork, time, long-term viability and testing, with teamwork and patience (faster delivery) being its two most important parts. 

So, instead of making a schedule for the project, agile ruptures it into smaller pieces called sprints that can be completed in a certain amount of time. This model puts adaptability, adaptability, collaboration, communication, quality, and early and continuous delivery at the top of its list of priorities. All of this is done to ensure that the result meets client requirements and can respond quickly to changes in the market. 

Conclusion

The Software Development Life Cycle (SDLC) is a set of rules for managing software projects that helps companies make high-quality software quickly and cheaply. It has six different parts: expectations, actions, outputs, guidance on how to do things, key people, goals, and written records. The SDLC is a continuous process that needs business experts, developers, QA staff, and stakeholders to work together.

Over time, the SDLC has changed, and the testing step has become a more important part of the process. At first, security steps were seen as less important and were put off until the testing stage. But this way of doing things has led to many security holes being found too late or not being found at all.

To make sure the SDLC works, it is important to stick to best practices and steps. During the planning phase, you'll do things like compare costs and benefits, make a schedule, estimate costs, and decide how to use resources. During the design phase, software needs are turned into a document called "design specifications," which is then reviewed by stakeholders to get their feedback and ideas.

During the execution phase, you write the code for the product and make sure there are clear rules about how and when to use the code. During the testing phase, bugs in the software are looked for. This is often done at the same time as the creation phase. During the software deployment phase, the program is put into a production setting so that users can try it out before it goes on the market.

In the end, the SDLC provides a structured management system for software development. This makes sure that the software is of high quality while keeping costs and time to a minimum.

The idea of a Secure SDLC (Secure Development Life Cycle) has gotten a lot of attention in the software business. This shows how important security practices are at every stage of the development life cycle. This means putting together different ways to make sure security, like penetration testing, threat modelling, code reviews, and architecture studies.

Adopting a Secure SDLC model has many benefits, such as saving money, making people more aware, reducing risks, improving software security, and finding system flaws early on. With the improvement of security testing tools, it is now easier than ever to make sure that SDLC is safe.

SDLC models are set up to make the development cycle run as smoothly as possible. The waterfall model, the iterative model, the V-shaped model, the spiral model, the prototype model, the agile model, and the big bang model are all common. Each model gives you a different way to deal with problems on a project. The waterfall model is best for projects that need more customer access and comments, while the Agile model is better for long projects with requirements that change all the time.

The Agile SDLC framework is becoming more popular because it is flexible and built on core principles like adaptability, customer engagement, lean growth, teamwork, time, long-term viability, and testing. Agile divides projects into smaller chunks called "sprints." It puts adaptability, collaboration, communication, quality, and early and continuous delivery at the top of its list of priorities to make sure the end result meets client needs and reacts quickly to changes in the market.

Content Summary

• The Software Development Life Cycle (SDLC) provides a structured framework for managing software development.
• SDLC helps in tackling challenges like changing requirements and technological advancements.
• This methodology offers clear objectives for each development phase.
• SDLC optimises the use of time and financial resources in software development.
• A typical SDLC has between five to seven phases, although more complex projects might have more.
• Traditional SDLC methods, like the waterfall model, are often linear.
• In modern SDLC methods, phases are sometimes revisited for improvements.
• The SDLC is an evolving process requiring regular updates from business experts, developers, and stakeholders.
• Security practices have transitioned from being a phase to being integrated throughout the SDLC.
• The secure-by-design approach is considered the best practice in modern SDLCs.
• Planning is the first phase involving cost-benefit analysis, scheduling, and resource allocation.
• The planning phase culminates in a software specification document outlining the project's requirements and goals.
• The design phase involves turning software requirements into design specifications.
• Stakeholder feedback is crucial during the design phase to prevent costly errors.
• Implementation follows the design phase, where the actual coding happens.
• The build phase involves adhering to predefined coding rules for uniformity.
• Both automated and manual testing occur in the testing phase.
• Quality assurance tests ensure the software meets customer demands.
• Deployment involves moving the software into a production environment.
• Many companies deploy to multiple environments for last-minute adjustments.
• The SDLC model chosen depends on the project details and desired outcomes.
• The waterfall model is a linear approach where each phase depends on the previous one.
• The iterative model encourages starting with a small set of requirements and refining the software over time.
• The V-shaped model runs in parallel with the verification and validation phases.
• The spiral model incorporates risk analysis and prototypes for gradual software improvement.
• The prototype model facilitates early customer feedback through working models.
• The agile model is incremental and iterative, allowing for rapid adjustments.
• Agile prioritises customer engagement, adaptability, and quality.
• The Big Bang model is a risky approach that leans heavily on the development phase.
• Agile models are gaining popularity due to their flexibility and responsiveness to change.
• Agile employs sprints, which are small, time-bound units of work.
• The number of phases in an SDLC can vary depending on the complexity of the project.
• Each SDLC phase produces a deliverable that serves as an input for the next phase.
• The SDLC needs to be periodically reviewed and updated to stay current.
• The SDLC has been around since the 1960s, but its core principles have evolved.
• Early detection of security vulnerabilities in a Secure SDLC saves time and money.
• A Secure SDLC keeps key stakeholders informed about security issues.
• Security measures, when integrated into the SDLC, mitigate overall business risks.
• Penetration testing, threat modelling, and code reviews are techniques used in a Secure SDLC.
• Secure SDLC aims for software that is inherently more secure.
• Adopting best practices in SDLC makes the development process efficient.
• Detailed planning is crucial to a project's success in any SDLC model.
• Code style guidelines help maintain uniformity across the development team.
• Testing is now often integrated into the development phase rather than being separate.
• Deployment strategies often involve using multiple environments to catch last-minute issues.
• Project length and changing requirements often dictate the choice of an SDLC model.
• The waterfall model is suitable for projects with stable requirements and limited customer feedback.
• Core principles of Agile include adaptability, customer engagement, and teamwork.
• Agile models are better for long-term projects with frequently changing requirements.
• The SDLC's primary goal is to produce high-quality software in the most efficient manner possible.