Software Development Life Cycle (SDLC): Methodology and Stages

In 2018 an estimated $836 billion was contributed to the US economy by the software development sector. Today, software represents an essential component of any successful business.

That means there are more companies than ever out there today developing new software solutions. Many of them are adopting the SDLC approach. This is otherwise known, in long-form, as the Software Development Life Cycle.

We’re going to go into detail on the methodology behind the SDLC. Then, we’re going to go through each of its 7 core phases in turn, so you know how software design in 2021 really works.

What Is the Methodology Behind the Software Development Life Cycle?

The Software Development Life Cycle has been designed in order to streamline the process of software development for developers. It’s designed as a 7 phase process to ensure that software development can be completed efficiently, with as few errors as possible.

It’s also designed to make the process of development easier for companies overall.

You may also have heard it referred to as the Systems Development Life Cycle or the Applications Development Life Cycle. All of these phrases refer to the same essential 7 phase process.

The cycle breaks down software development into several core stages. These are in relation to planning, creating, testing, and deploying, with several phases included in all of these stages. There’s also a final stage, known as maintenance, which is reserved for after a solution has been developed.

Some more advanced versions of the SDLC include 10 phases, rather than 7. These are usually for more advanced software solutions, which require greater effort overall.

Phase 1: The Planning Phase

The first phase of the Software Development Life Cycle is perhaps the most important of them all. This is the planning phase, which must be completed before any actual development on a project can commence.

The project manager will use this phase to outline the terms of the development cycle. This will include how many people will be working on the project, and how long they expect it to take overall.

It’ll also involve budgeting how much the development process will cost to complete.

Much of the initial planning involves financial and organizational considerations. The actual software itself will not be developed in detail at this stage; that comes next.

Instead, though an idea is in mind, a plan will be made to ensure that a software’s development is actually feasible.

When it comes to larger companies, this phase will include involvement from board members and shareholders. It’s about conceptualizing what the end result of the software will actually look like before development commences.

Phase 2: Defining Requirements

This is what can be seen as a secondary addition to the overall planning phase. After the costs and workforce aspects of a project have been planned out, a project manager defines the requirements of the software.

This additional planning phase involves outlining what exactly this software intends to do. This is in terms of the solution it is providing the customer, as well as who the customers are.

The software might be designed for businesses, or for the customer as an end-user. A lot of software today is designed with both of these target markets in mind.

This is also the stage where some of the essential features of a piece of software will be conceptualized. This involves ascertaining what traditional features will be needed.

These include things like search functions, profiles, or security features. Then, the project manager needs to consider any brand new features which need time to be developed.

Finally, this is where an inventory is considered, should additional machinery be required. Certain software may require advanced machines that are controlled by the software itself.

If this is the case, this needs to be acknowledged before moving to phase 3.

Phase 3: Design and Prototyping

This is where the design of the software actually begins.

After the initial two planning phases, developers will get to work on prototyping the software.

The nature of this phase will depend on the software in question. Sometimes, this phase can take an extremely long period of time due to the complexity of the project itself.

Prototyping is a vital part of the process. This is because it ensures that features and aspects can be trialed before developed fully.

Other models, such as Agile or the waterfall model, may also be implemented here.

The extensive nature of this phase also means a lot of aspects of software design must be considered. These include, but aren’t necessarily limited to:

• Platforms – deciding what the software will run on (Windows, Mac, Mobile, etc)
• Programming – the coding language and how problems will be solved
• Communications – how software talks to itself
• Architecture – the overall design of software
• UI and UX – the ways in which the end-user interacts with software
• Security – the ways in which software remains secure

All of these can be complex design processes in their own right. Security for instance can include consideration of CISSP Security Certification. Certain developers spend decades furthering their understanding of UI and UX alone.

It’s important to note however that this stage doesn’t involve actual software development. This is instead focused on firming up design; development comes next.

Phase 4: Developing the Software

Finally, in phase 4, the actual development of software commences. This development will be driven by prototypes, many of which are likely to have failed.

It’s also driven by the design principles that were created and perfected in phase 3 of the process. Software development is a costly and time-consuming endeavor, which is why the actual development doesn’t happen until this far into the process.

The development itself may be handled by an entire team, who focus on different areas.

Or, it could be the work of one person. This is dependent on what the project is and the barriers that were set earlier on in the life cycle.

Documentation, such as writing user guides, is also usually handled during this phase. This is to ensure that users are able to understand the software, without having created it themselves.

Once the development itself is complete, the project moves into the lengthy testing phase.

Phase 5: The Testing Phase

Within the testing phase, developers ensure that everything they’ve developed is working properly.

This involves recognizing and fixing any serious glitches that may have occurred during programming. It’s common for larger companies to outsource certain aspects of the testing phase.

This is because problems can arise from seemingly random areas within a software code. The more people testing a developed piece of software, the more likely it is that all the errors are found and fixed.

Testing doesn’t just involve glitches, it also involves checking aspects like UI and security. All of these areas may need improving before the software is ready to be launched to market.

Phase 6: Deployment

Finally, once all testing has been completed and all errors are fixed, the software is deployed to market.

This will usually involve extensive marketing initiatives, to advertise the new software to customers. The nature of this marketing will depend on the company and the software itself.

Some may provide incentives for early adopters, whereas others may simply launch with little fanfare.

However, the launch of the software doesn’t signify the end of the development process.

Phase 7: Monitoring, Maintenance, and Updating

The work of a software developer is never really done. Even after a software solution has launched, it will require constant monitoring.

This is to keep checking for any errors or glitches that may arise following the product launch. Developers will also typically be required to update software often.

This can be in the form of adding additional features to the software, which can again be advertised. Or, it may involve redesigning software to launch an entirely new version to market.

This is the nature of software development in 2021; nothing is ever completely finished. This is why phase 7 is the longest phase, as it never really ends until a new version of the software has been launched.

Monitoring teams themselves will vary in size, dependent on the size of the project and the company itself.

This is the full phase breakdown of the SDLC. It’s a methodology followed by the majority of developers making software solutions, videogames, and other technology available on the market today.

Where Can I Find Out More?

You should now know what the Software Development Life Cycle is, and what its many phases are. But like anything relating to software development, it isn’t the easiest thing to get your head around.

If you’re in need of further information regarding the SDLC or anything else related to tech or software development, make sure to take a look through some of the previous posts on our website.