The Software Development Lifecycle - SDLC
Every piece of software starts as an idea and works its way through a series of stages until a release is developed and deployed. The Software Development Lifecycle (SDLC) is a process that is widely used by businesses to develop and deploy software that is of exceptional quality.
In this blog, we’re looking at this process, the various stages involved in it, and the different models and methodologies available. Read on to know more.
What is the Software Development Lifecycle?
The Software Development Life Cycle or SDLC, is a systematic method for making high-quality, low-cost software in the shortest amount of time. A common analogy used in the IT industry is that of building a house. The SDLC serves as the blueprint for building the software from scratch. The detailed plan describes how to develop, maintain, replace, and change or improve specific software. The life cycle focuses on enhancing software quality and the development process as a whole. Depending on the scope of the project, the entire process is normally divided into six to eight steps.
Essentially, the SDLC is a method for measuring and improving the development process. It enables a thorough examination of each stage of the process. As a result, businesses can maximise efficiency at each stage. As the capabilities and complexity of computers continue to increase, developers are under immense pressure to deliver cheaper software faster and meet growing customer expectations. SDLC helps achieve these diverse goals by identifying bottlenecks and higher costs and rectifying them so that operations run smoothly.
How Does SDLC Work?
The Software Development Life Cycle basically defines each task involved in the creation of a software application. With SDLC, businesses can anticipate costly mistakes thereby minimizing waste, reducing repetitive rework, and last-minute fixes. This helps to improve the efficiency of the development process. Additionally, continuous monitoring and measurements ensure that the project goes according to plan and remains a viable investment for the company.
SDLC begins by assessing the existing systems for flaws. It then defines the new requirements of the system. It then goes through phases of analysis, planning, design, development, testing, and deployment to build the software. There is also a strong emphasis on the testing phase in the SDLC methodology to ensure quality code in every cycle.
Stages of SDLC
Quality software is created using a well-defined step-by-step process. If any of the steps are ignored or followed shoddily, your software development efforts will be futile. The systems-development life cycle has traditionally been divided into five stages. However, this number has now increased to include two, three or even up to five additional stages in order to more clearly define the specific actions required to meet different goals. In this section, we'll go over the seven most common SDLC stages:
Planning
The goal of this first step is to determine the scope of the project and develop appropriate solutions. This includes calculating labour and material costs, developing a timetable with specific goals, and forming project teams and a leadership structure. It can also include feedback from potential clients, developers, subject matter experts, sales representatives, and other stakeholders. This step sets the course for the software development process. In addition, it establishes boundaries to prevent the project from expanding or diverging from its original purpose.Systems Analysis and Defining Requirements
In this phase, existing systems are analyzed to understand what end users need and expect from the software. The team also take into account the functional requirements of the project and the resources required to build it.Systems Design and Prototyping
This third stage clearly describes the specifications, features, and operations required to meet the functional requirements of the proposed system that will be implemented. It demonstrates a basic, working version of the application. This prototype can also be shown to stakeholders for feedback and improvements. Changing the prototype is much easier and less expensive than making changes to the product in the development phase.
Software Development
This stage marks the completion of the preliminary processes and the beginning of the production phase. This is where the actual writing of code begins. A small project can be handled by a single developer, whereas larger projects may require multiple teams. This process also involves many other tasks such as finding and fixing errors, waiting for test results, or compiling code. SDLC accounts for all these delays and allows developers to work on other duties as well.
Integration and Testing
This step includes system integration and testing to determine whether the proposed design meets the original set of business objectives. Each function is tested to ensure that it works properly. Performance testing ensures that the different parts of the application work together seamlessly, eliminating any lags or hangs. User satisfaction and usage increase as a result.
Implementation/Deployment
This sixth stage involves writing most of the code and then putting the software into production. Users can then access the application.
Operations and Maintenance
At this point, the development cycle is almost done. The application is complete and is being used by customers. They find bugs that were not discovered during testing, and also provide feedback for additional functionalities to boost performance. New development cycles can be launched for fixing these errors and adding new features.
SDLC Models and Methodolgies Explained
Now that we’ve understood the phases in SDLC, let’s take a look at the SDLC methodologies. Here are some models to consider:
Waterfall
Waterfall is widely regarded as one of the most traditional SDLC methodologies. It's also a very simple approach: complete one phase before moving on to the next. Each stage is independent of the previous stage and has its own project plan.
Pros:
- Each phase can be reviewed for continuity and feasibility before proceeding
- Very easy to understand and manage
Cons:
- Lack of speed and flexibility for long-term projects
Iterative
In this model, developers make an initial and basic version of the software first. They then review and improve upon this basic version in many small steps or iterations. This method is generally followed for very large applications.
Pros:
- Generates a functional version of the product early on in the process
- Less expensive to implement changes
Cons:
- Can exceed its scope fast
- Depletes resources quickly due to its repetitive nature
Spiral
The Spiral model borrows from the repetition in the Iterative model. The project iteratively spirals through four phases (planning, risk analysis, engineering, and evaluation) until completed. This model is also typically used for large projects.
Pros:
- Very flexible
- Allows for multiple rounds of fine-tuning
- Lot of room for customization and customer feedback
- Helps to avoid and mitigate risks early on
Cons:
- Your project could get stuck in a never-ending spiral
-
V-Shape
The V-shaped model, also known as the Verification and Validation model, evolved from Waterfall and is distinguished by a testing phase for each development stage. Each stage starts only after the previous one has ended, just like in the Waterfall model.
Pros:
- Useful when there are no unknown requirements
Cons:
- Difficult to go back and make changes
Big Bang
This method is an oddity in SDLC methodologies as it doesn’t have a set process to follow. Very little time is spent on planning and a large proportion of the resources go towards development. This model is typically used for smaller projects, and is not recommended for large or complex projects.
Pros:
- Very simple and easy to implement
- There is no formal procedure, so it is easy to manage
Cons:
- High-risk model
- Can incur huge expenses if requirements are misunderstood
Agile
The agile model generates continuous releases, each with minor, incremental changes from the previous one. The product is also tested at each iteration. The main focus of this approach is customer experience and input.
Pros:
- Faster delivery
- Improved customer satisfaction
- Bugs and errors are identified and addressed before they become big issues
Cons:
- The project could go off-track if the team relies heavily on user inputs
Rapid Application Development (RAD)
Rapid application development (RAD) is a software development methodology that prioritizes rapid prototyping over extensive planning. It involves the process of collecting customer requirements through workshops or focus groups, early prototype testing by customers using iterative concepts, reusing existing prototypes (components), continuous integration, and rapid delivery. It is generally not recommended for smaller projects.
Pros:
- Reduces development time
- Enables integration from the beginning
- Reduces manual coding due to the reusability of components
- Adaptable and flexible to changes
Cons:
- Difficult to manage
- Not suitable for higher risk projects
- Not compatible with all applications
All of the above SDLC models provide different processes to achieve software/product development goals. Finding the best SDLC methodology for your business is heavily influenced by not only the expected outcome, but also the parameters under which the project is carried out. Always ensure that the developers you hire have experience in the model of your choice.
Integrating Cybersecurity into SDLC
Unfortunately, security tends to lag behind functionality, particularly in software development. The reality is that security should not be treated as a separate concern; rather, it should be inherently integrated into the process of designing software.
However, here is a significant obstacle to overcome: a staggering 86% of developers do not consider security a top priority when writing code. Research indicates that more than half of developers struggle to safeguard their code against common vulnerabilities. Why does this persist? The pressure of time constraints and a lack of guidance from managers regarding secure coding practices are major roadblocks, as highlighted by 24% and 20% of developers, respectively.
Forward-thinking companies need to understand this challenge and adopt long-term strategies. Investing in high-quality and secure code minimizes future fixes. Here are some strategies you can implement to make cybersecurity a part of your SDLC process:
Penetration Testing in SDLC
Penetration testing, or pen testing, isn't just about finding flaws in your software; it's a vital gauge for the overall health of your Software Development Lifecycle (SDLC). However, it's time to shift focus and use pen tests to unearth issues in your processes, not just the code. While automated tests from third parties are efficient, they can't replace the human touch. Humans, despite being slower and more expensive, can mimic hackers, offering a nuanced evaluation of how an application responds to a pen test. This human touch may catch responses that automated tools could potentially miss.
Meeting Regulatory Standards
Shifting left is a technique in which security and compliance testing occurs earlier in the SDLC, rather than waiting until the end to test the final product. When you infuse security into coding practices and development processes from the beginning, it maintains consistency and ensures that the code meets security standards and compliance requirements. Additionally, incorporating regular audits into the process can help you identify issues early on and correct them before they cause major problems.
Threat Modeling in SDLC
Hackers will steal anything valuable they can get their hands on. When you're building a cool new application, they will undoubtedly target it, especially because intellectual property is such a desirable prize for them. Threat modeling is all about being smart and outsmarting the bad guys to keep your things safe. It is an excellent way to identify potential vulnerabilities in your application and raise awareness about the security implications of your designs. With threat modeling, developers can gain a fresh perspective on their designs and proactively consider ways to address potential threats from the beginning.
DevSecOps
DevSecOps (short for Development, Security and Operations) is the software development approach that is all about shifting left and ensuring security from the very beginning. DevSecOps ensures continuous integration from planning and design through development, QA/testing, release, and production operation. To learn all about this approach, check out our blog post on the same.
Security Automation within SDLC
Automated security tools streamline the process of identifying and addressing vulnerabilities in software development. These tools check code for security flaws, keep an eye out for unusual activities on the infrastructure, and notify users of any potential violations. They act like the constant 'watchdog' that never sleeps and always has a keen eye out for potential threats.
Conclusion
The Software Development Life Cycle is an essential framework required to build products that satisfy a strong market demand. SDLC's overarching goal is to establish a standard path for the software development team to follow. Without this clear path and sense of direction, development efforts are likely to fail.
Learn how Threat Intelligence can help enhance your SDLC by integrating security in the processes right from the start.
Book a demo
with one of our experts today to know more.
