Software Development Life Cycle (SDLC) Demystified: A Thorough Beginner’s Handbook in Software Engineering
1. What Is the Software Development Lifecycle or SDLC?
The Software Development Life Cycle (SDLC) is a process used in software engineering to design, develop, test, and deploy software applications. It is a structured approach to software development that helps organizations improve the quality of their software products, reduce costs, and minimize risks. The SDLC encompasses several phases with goals, deliverables, and stakeholders.
In this article, we will discuss the various phases of the SDLC, including their benefits and challenges. We will also provide some best practices for implementing the SDLC in your organization.
2. Agenda for this Series
The remainder of the topics in this series can be found below:
3. What Are the Main Principles of the SDLC?
The Software Development Lifecycle (SDLC) is a structured approach that allows software development teams to manage the delivery of large software projects. It can be characterized by the following:
4. What Are the 7 Phases of the SDLC in Software Engineering?
Some people define the SDLC as consisting of 5 stages. Others, on the other hand, prefer the 7-stage definition, which includes Planning and Support (or maintenance). We have adopted the 7-stage SDLC simply because it caters to the process end-to-end.
4.1 Stage 1: Planning
4.1.1 What Activities Occur in the Planning Phase of the SDLC?
The planning phase is the first step in the SDLC. It involves defining the project’s objectives, scope, and requirements. The planning phase is critical because it lays the foundation for the entire project. Some of the key activities in this phase include:
4.1.2 Who Are the Stakeholders of the SDLC Planning Phase?
The stakeholders involved directly in the planning and preparation of a software development project are typically:
4.1.3 SDLC Planning Tools and Techniques
While planning and allocating resources, delivery managers ideally aim for the following targets:
4.2 Stage 2: Analysis
4.2.1 What Activities Occur in the Analysis Phase of the SDLC?
The analysis phase is where the software requirements are analyzed in detail. During this phase, the project team will work with the stakeholders to identify the business requirements, functional requirements, and non-functional requirements. Some of the critical activities in this phase include:
4.2.2 Who Are the Stakeholders in the SDLC Analysis Phase?
The stakeholders involved directly in the analysis phase of a software development project highly depend on whether you are using an Agile Methodology or a Waterfall project management approach. Typically, they would be:
4.2.3 SDLC Analysis Phase Techniques
Two criteria must be met for this stage to be successful:
4.3 Stage 3: Design
4.3.1 What Activities Occur in the Design Phase of the SDLC?
The design phase is where the software architecture and design are created. During this phase, the project team will create the software design, including the system architecture, database design, user interface design, and program design. Some of the key activities in this phase include:
4.3.2 Who Are the Stakeholders in the SDLC Design Phase?
The stakeholders often involved in the design phase of the SLDC are as follows:
The design phase of the SDLC typically involves two main efforts: creating a solution design from software components and documenting, socializing, and approving the design.
4.3.3 SDLC Design Phase Techniques
4.4 Stage 4: Development
4.4.1 What Activities Occur in the Development Phase of the SDLC?
The development phase is where the actual software is developed. During this phase, the project team will write the code, perform unit testing, and integrate the components. Some of the key activities in this phase include:
4.4.2 Who Are the Stakeholders in the SDLC Development Phase?
At the core of any development team are those responsible for implementing new features. These are:
4.4.3 SDLC Development Phase Techniques
Developers must produce working software that meets today’s quality standards regarding coding and functionality. The techniques used are numerous, in fact, too many to list here. However, we will name a few to illustrate the idea.
4.5 Stage 5: Testing
4.5.1 What Activities Occur in the Testing Phase of the SDLC?
The testing phase is where the software is tested for defects and errors. During this phase, the project team will perform various types of testing, such as unit testing, integration testing, system testing, and acceptance testing. Some of the key activities in this phase include:
4.5.2 Who Are the Stakeholders in the SDLC Testing Phase?
Testing activities have broader to include a range of specialists, of which we name the following:
4.5.3 SDLC Testing Phase Techniques
Software Testing is always a great place to start when looking for ways to optimize your delivery. One significant factor immediately comes to mind: test automation.
4.6 Stage 6: Deployment
4.6.1 What Activities Occur in the Deployment Phase of the SDLC?
The deployment phase is where the software is deployed to the production environment. During this phase, the project team will install the software, configure it, and perform any necessary data migration. Some of the key activities in this phase include:
4.6.2 Who Are the Stakeholders in the SDLC Deployment Phase?
Deployment has increasingly become more sophisticated through DevOps practices. This has led to new specialised roles being created to cover previously unknown areas:
4.6.3 SDLC Deployment Phase Techniques
Deployment to production has moved to a new level with continuous delivery, automated deployment, and frequent releases. The infrastructure supporting automated and advanced deployment methods (tools and processes) falls under DevOps. DevOps practices allow the fusion of development and operations in a single, streamlined process.
4.7 Stage 7: Support and Maintenance
4.7.1 What Activities Occur under Support and Maintenance?
The maintenance phase is where the software is maintained and updated. During this phase, the project team will fix defects, perform upgrades, and make enhancements to the software. Some of the key activities in this phase include:
4.7.2 Who Are the Stakeholders in the SDLC Maintenance Phase?
Most software support tasks revolve around running a service desk, which includes the following experts:
4.7.3 Support and Maintenance Techniques
Triage, time management, SLA awareness, and customer satisfaction are the hallmarks of customer support.
5. What Are the Benefits of Having an SDLC in Software Engineering?
A well-defined Software Development Life Cycle (SDLC) contributes to various aspects of software engineering, leading to several advantages. Here’s how it helps achieve the specified points:
A well-defined SDLC is instrumental in achieving these goals by providing a structured framework that promotes efficiency, collaboration, and quality throughout the software development process.
Balancing flexibility with structure
The SDLC can be very structured, limiting the project team’s flexibility.
Balancing flexibility with structure is key to ensuring that the project team can respond to changes in requirements or other issues that may arise.
6. Improving Deliveries and the SDLC
6.1 Why Does the SDLC Need Continuous Improvement?
The fundamental ideas of the SDLC have changed very little over the past 50 years, but its implementation details have undergone a huge metamorphosis. This change is visible in the following areas:
This expansion and sophistication meant that the implementation details of the SDLC (or how exactly it runs as a process) have become increasingly relevant to its efficiency and effectiveness in affording the successful delivery of software projects. As with anything complex, the SDLC requires continuous maintenance, adaptation, and improvement.
In the next few sections, we will tackle some powerful techniques to improve your SDLC.
6.2 Process Standardization
Employees sometimes view standardization as a means for curbing creativity, innovation, and personal initiatives.
While that statement may not be entirely untrue, process standardization across the organization guarantees minimum outcome variations (see article on Six Sigma) and ensures improvements are applied consistently.
What is essential in standardization is that you pick time-proven methods and use them consistently. You can always run continuous improvement exercises on those methods for optimal results.
If you create bespoke processes for your organization, there will be significant implications. While a customized standard of operations may work better for you in the long run, its initial cost can be pretty high. Ideally, you want to use a vocabulary that everybody can understand so that integrating new people into your teams or discussing issues with customers remains simple.
6.3 Reducing Non-Value-Adding Work
Taiichi Ohno, one of the top contributors to the world-famous Toyota Production System, implemented the following technique for eliminating waste on the shop floor of the Toyota production plants to an astounding degree of perfection. The process is as follows:
This five-step process should not be confused with scientific management (a.k.a. Taylorism). Scientific management, proposed by Frederick Taylor in the 1880s, was likely to be counter-productive as employees found ways to game the system.
This method is a radical deviation from the statistical analysis of data collected remotely and analysed behind a comfortable desk. Its advantages include gathering firsthand information as seen through experienced eyes. This method is known in Toyota as Genchi Genbutsu.
6.4 Team Structure and Performance
Although it would not make much sense to have a prescription for team size and profiles for its members, some rules of thumb apply in non-complex environments. Here are some expert opinions on the matter:
6.5 Retrospectives, Kaizen Workshops, and Continuous Improvement Processes
At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behaviour accordingly.
— The Agile Manifesto
As the organization grows and pressure for faster and better deliveries increases, people will find less time to improve what they do. In his timeless classic The 7 Habits of Highly Effective People, Stephen Covey describes this phenomenon as “sharpening the saw”.
Even if individual initiatives were made here and there, these would continue to be local, spurious improvements and cease to suffice.
To maintain software delivery in top shape, continuous improvement methods must be ingrained in the DNA of the system. In addition to that, they also need to be amalgamated into a single, system-wide activity. Scrum uses retrospectives after each sprint. The double activity of Kaizen and Hansei is slightly different, but the objective is the same.
Such exercises are essential for morale; they convey to the staff that the company is committed to continuously improving its people and processes, not just about the present but also the future.
7. Stability vs Adaptability: Responding to Change in the SDLC
7.1 Working in a Dynamic Environment
The software development industry has undergone significant changes, which can be readily seen in the remarkable technological advances of the last two decades and the prevalence of software in every area of life.
This rapid and boiling dynamic impacts software development, specifically the Software Development Lifecycle. While technology has its own lifecycle, it constantly drags software development with it. Every time a new technology is invented, customer preferences evolve, and new methods of integrating the technology into the development process become vital.
Therefore, the SDLC must evolve. As mentioned before, while its fundamental concepts remain the same, its implementation is constantly changing.
7.2 Technology Lifecycles
The pace at which software or any other technology-based industry changes is breathtaking. Sometimes, that leaves us with a feeling of helplessness that’s difficult to ignore.
The question then becomes, how do we, as professionals in the software industry, keep producing premium-quality products despite the ever-changing nature of technology, tools, techniques, and methods that come with it?
It might help to look at the software industry’s evolution not as a homogenous, monolithic entity but as four significant sub-fields, each characterised by a predetermined lifetime.
| Subfield | Description | Lifetime |
|---|---|---|
| Tools | Programming languages, frameworks, and database engines. | < 10 years |
| Delivery Methods, Customer Preferences | Project management techniques, project delivery methodologies (Agile, Waterfall, DevOps), business needs (eCommerce, payment methods, IoT, smartwatches, cloud technology…) | 10-20 years |
| Tech Concepts | Personal computers, quantum computing, digitization, internet, smartphones, AI…) | 20-30 years |
| Business Management | Taylorism, The Toyota Way, Lean Manufacturing, Six Sigma, Operational Excellence | 30+ years |
The lifetime in this context does not represent an expiration but the average duration before a newer concept arises and challenges the status quo.
Like any other field in science or technology, historical progress seems to happen in jumps, followed by plateaus, rather than monotonic, incremental improvement.
7.3 Measured Responses to Disruptions
What would be an adequate response from your organization for the above four disruption levels? Below are some thoughts.
Level 1: Short-Term Fluctuations
Level 1 entries appear and disappear every day. Use reliable technology, always! The gravest mistake you can commit would be trying to catch up with their destructive pace.
Level 2: Big Changes
Level 2 entries are technological trends that change dramatically every decade or two. Consider the emergence of digital payments, for example. While people still use cash nowadays, they would also like to take advantage of the convenience of mobile phones or watches.
Although embracing those new methods is not strictly vital, not doing so places your business in a less-than-ideal situation vis-a-vis competition.
Level 3: Major Disruptions
Looking at entries from Level 3, we immediately recognize game-changing technological revolutions that put so many giants out of business overnight.
Those past giants failed to reinvent their value proposition and were swiftly replaced by newcomers who leveraged new technologies to offer innovative solutions.
Level 4: Paradigm Shifts
It is somehow fortunate that the more potent concepts of Level 4, those that make a business successful or otherwise, change exceptionally slowly. There is more than enough time for everyone to master them.
These occur as part of larger sociological, economic, or technological revolutions. Because Level 4 fields, such as Operational Excellence and Complexity Theory, sit at the top of the hierarchy as one of the lot’s most stable concepts, ideas, and mental constructs, it makes sense to consider them and invest time in applying and mastering them thoroughly.
8. Final Words
We hope this article has allowed you to understand the Software Development Lifecycle (SDLC) and the most popular techniques and tools for its implementation. We also hope that we have successfully conveyed the need for continuous improvement in pursuit of Operational Excellence.
The SDLC is of prime importance to any software developer as it’s the common denominator, the main thread in the story of any development team.