SDLC: System Development Life Cycle

For years now, the Software Development Life Cycle, or SDLC for short, has cemented itself as the de-facto process to help build information systems, systems engineering, and software engineering from the ground up by encompassing key phases that can be grouped in planning, implementation, and maintenance of the system solution. 

The SDLC has grown to be critical thanks to its standardized phases that manage a balancing act between costs, quality, and time to meet modern business demands, urgency, complexity, and to top it off, with tight budgets.

Table of contents:

1. What is system development life cycle? 
2. Why should you have a system development life cycle in place?
3. The SDLC Phases.
4. SDLC: Methodologies of System Development.
5. SDLC Roles.
6. Conclusion.

What is system development life cycle? 

Let’s briefly explain. In general, SDLC is a closed loop in which each stage affects the actions in subsequent ones and provides clear information for future stages. To answer specific questions and ensure consistency in your development process, usually, all six stages try to effectively and consistently influence each other.

But before we run and take off by explaining each of the SDLC phases, let’s first define what a system is. By industry standards, a system is a combination of hardware, software, and human resources that perform the assigned tasks of collecting, processing, and displaying information. 

Within that context, the SDLC helps the system come to fruition. Some may wonder why it’s so important to develop and operate information systems in a cyclical fashion and to that, we can find the answer as it’s traced back to the constant changes in conditions in which the information system is located that influence the outcome of the system.

Whether it’s upgrading to new hardware, updating software development tools, increasing user requirements, or scaling the amount of information in the business environment and domain areas, a system’s life cycle always consists of planning, implementing, and maintaining. Of course, through iterative processes and changing business demands, there are now more phases involved including analysis, design, development, testing, and decommissioning or transition to a new information system, all of which have become crucial and can be used depending on the nature of each project.

We’re living in an Agile world where the Agile methodology has taken over most software development projects as it helps create products iteratively and flexibly to navigate and manage requirements of information systems with ease and effectiveness. The Agile methodology can work in harmony with the SDLC process by pairing phases with iteration frameworks. 

As a result, each stage will have roles of project participants who will take an active role in their tasks. In this article, we will focus on the main project roles which include the project manager, analyst, architect, developer, tester, and DevOps. It’s worth noting that each project participant plays an important role across the SDLC and they all have a direct impact on the overall wellbeing of projects. 

Why should you have a system development life cycle in place?

Alleviating software development complexity is chief among the key best practices for developing software. To that end, using the SDLC process goes a long way in compartmentalizing and breaking down robust tasks, into smaller, more manageable tasks that are easier to measure and achieve. Thanks to its framework of structured phases, those involved in the SDLC can help shape the project and manage it in a more streamlined fashion. 

In addition to these reasons, it’s also extremely valuable to have an SDLC in place when developing software as it helps transform an idea project into a fully-fledged, functional, and fully operational system. The SDLC covers both the technical and operational aspects of building software, encompassing activities such as process and procedure development, change management, policy development, user experience, impact, and adherence to security regulations.

It is very easy to explain the system development life cycle using the analogy of pouring water into glasses. When water is poured from one glass to another, in the end, if done carefully, you will still have a full glass of water without losing a drop. At each stage, you will transfer the most valuable information throughout the project, focusing on the goals and objectives of the project, and making changes to the project where necessary to improve the user experience.

To top it off, the SDLC process helps plan ahead of time and analyze the structured phases and goals of a specific project so it becomes easier to tackle, delegate, and address. Goal-oriented processes don’t follow a one-size-fits-all methodology; instead, they are responsive and quick to adapt to changing user and requirement needs, which is why a thorough plan goes a long way in defining costs and staffing decisions, providing clear goals and deliverables, measuring performance, and validating each phase of the life cycle to improve quality. 

The importance of the software development cycle comes first in any software development process. The quality, lead time, and budget of the output product depend on properly-constructed cycles. This will save the team efforts of programmers, testers, and PMs while increasing the survivability of the product in the conditions of real user operations. Next, we will cover the main phases involved in the System Development Life Cycle to review what each entails.

The SDLC Phases

The SDLC phases are designed in a way that progressively develops or alters a system across its life cycle. If followed through from beginning to end, the SDLC will help deploy a fully-operational, high-quality system that meets and/or exceeds client requirements, all within the specified time and budget constraints. 

Next, we’ll be dissecting each of the SDLC phases.

Planning

Setting a strong foundation and defining a clear understanding of a project is crucial to the success of any information system. For this reason, the SDLCs first phase is planning where stakeholders and all parties involved in the project participate to clearly define requirements and the nature of what the information system will need to solve. The planning phase helps delineate all subsequent tasks so they can be planned and budgeted for accordingly. 

To achieve a comprehensive planning cycle, members of the project need to have a deep understanding of what tasks the future information system needs to solve. With that foundation as context, the quality and time spent on the planning phase have a direct correlation to the success of the project. 

In this phase, the team defines the key components of the project at a high level, they define the environment in which the information system will operate along with the necessary technical, budget, and human resources required to complete the project. 

Analysis 

Once a thorough plan is set in place, next comes the analysis phase. This crucial phase is where project members dive deep and define the technical requirements of the system so they can be properly addressed. 

The analysis phase in SDLC allows you to receive feedback and support from relevant internal and external stakeholders. At the same time, you will need to think broadly about who your potential users will be. At this stage, you will include your clients, designers, management team, programmers, testers, and other technical team members. In general, this stage is all about answering the question: “What problems need to be solved?”

Also, during the analysis phase, the team defines the inputs and outputs of the data flow in and out of the system by undertaking a thorough system analysis of the business processes that need to be covered and solved by the future system. 

This phase is closely tied to documenting all the project specifications and the team usually takes sufficient time to properly document each detail for future reference.

Design

Progressing down the SDLC, the next phase that typically follows analysis is the design phase. In this phase, all the documentation that the team created in the analysis phase is used to develop the actual technical documentation of the project. This could be a statement of work in corporate or SRS in IEEE830 format.

In the design phase, project members define the structure of project components as well as key elements of the system by defining the interfaces that will exchange data within the workflow. It’s very common for the project teams to use UML diagrams in the design phase to design the system’s architecture.

Development 

Ah, what many consider the pièce de résistance, the development phase. By far, one of the richest phases in the SDLC process, the development phase is used to write the actual code of the system’s software, develop and deploy the system’s hardware, configure cloud systems, implement interaction protocols, and prepare the primary test data. So, you can see why it’s such a big deal.

During the development phase, thanks to the UML diagrams that were built in the design phase, project teams carefully implement the system’s architecture in program code by creating methods and algorithms for information processing, preparing the project outputs, and building a monitoring system for the system. 

Testing and deployment

Right after the development phase, comes testing and deployment. What does this phase entail, really? Well, for any system to work as intended, it needs to be thoroughly tested and tested again until the results match the expected outcome.

This phase is crucial as it directly impacts the quality of the outputs as it’s where the Quality Assurance (QA) team takes assertive steps to verify and validate the elements of the information system across multiple software testing scenarios, be it through a black box or white box testing. 

In this phase, the QA team also helps improve code coverage through automated tests and using resources from both the backend and the frontend of the system. Here, the QA team also carries out trial runs to collect system behavior data for insights on what can be improved or tweaked for a superior user and system experience. 

Once the production environment is thoroughly tested, it’s primed to be deployed and out into the world. Typically, this task is performed by the DevOps team with the help of CI/CD methodology. Also, deployment entails the implementation of cloud services, hardware, monitoring systems, the configuration of maintenance protocols of complex data, security measures, and data access restrictions.

Maintenance

The SDLC doesn’t necessarily stop once the system is out living and breathing. What comes next is the maintenance phase where the project teams carefully assess the system to help reduce the cost of operation and maintenance through several methods like feedback collection, error detection and elimination, and optimal performance standards.

For example, a system’s maintenance may also include the tracking and monitoring of the system's security, eliminating potential risks and threats, assembling a list of functionalities that need to be updated, adapting the system to environment changes and new business requirements, and more. 

Read more about the SDLC phases in this article.

SDLC: Methodologies of System Development

SDLC is not an isolated process, in fact, there are many methodologies available that are paired successfully to meet unique project needs. Each methodology has its distinctive collection of pros and cons that should be weighed down to decide which aspect or trait will yield the best results for an SDLC project. 

In general, SDLC in information systems is defined by a model and described in the form of a methodology. The life cycle model or paradigm defines the overall organization and, as a rule, its main phases and principles of transition between them. The methodology or method determines the set of actions, their detailed content, and the roles/responsibilities of specialists at all stages of the selected software development model.

From Agile to Waterfall as the most prominent methodologies that can be tied to the SDLC effort, there are other noteworthy options to consider including the prototyping model, the iterative model, the spiral model, the v-shape model, Scrum, Kanban, the fountain model, the build and fix model, the Rapid Application Development (RAD) model, and many more. 

Let’s dissect some of the most widely used SDLC methodologies next.

Waterfall

Waterfall is something of a staple in the SDLC sphere. Many associate this methodology with a traditional way of doing things, following a sequential and linear approach to developing software. 

Thanks to this systematic and rigidly standardized approach, Waterfall consists of a series of stages and each one needs to be completed before moving on to the next one, without exceptions. A typical and straightforward Waterfall workflow includes requirements, design, execution, testing, and release.

Rapid application development (RAD)

Adaptive and fast by nature, the RAD model puts less emphasis on planning and more on adaptive tasks. What do we mean by this? RAD favors rapid prototypes as a means to substitute development and testing cycles, making it one of the most popular SDLC models for software as it allows for rapid software development without the need to develop schedules at the beginning of each dev cycle.

RAD’s development model was first conceived back in the 80s to solve the need of developers looking for a more effective solution than the traditional Waterfall. One of the biggest faults of the Waterfall methodology, and one that most developers complain about, is the complexity to change core functions and software features. In RAD, the development evolution is continuous and flexible to suit changing business needs, which is a must in today’s modern environment.

Prototyping

When you hear the word prototype, if you’re like us, your mind wanders off to miniature airplanes or cars that we sometimes referred to as prototypes.

Well, in the context of software development, it’s not too far from the truth. The prototyping model builds prototypes or small replicas of the software to emulate how the final product will behave with all the functioning aspects built to behave as expected.

By having the product emulate expected behavior on a small scale and in a controlled environment, it’s easier for developers to visualize components to ensure the software solves the needs it was designed for. 

Prototyping has different variants which are typically grouped as throwaway or evolutionary. Throwaway prototypes create replicas of the software that will eventually be discarded while evolutionary prototypes create a robust replica that will continuously be refined until it reaches its final version.

Spiral 

Considered one of the most popular methodologies for SDLC, the Spiral model is an exceptional solution for risk handling. This model’s key differentiator is its diagrammatic visualization which resembles that of a spiral with many loops across the spiral which can vary from project to project. 

Each loop within the spiral is called a phase and they can be defined based on the needs of the project managers in terms of risks. Another interesting aspect of the spiral model is its radius which represents the costs of the project while the angular dimension sheds light on the progress being made on the project in each current phase. 

Many project managers favor the spiral model for large and complex projects because it leverages the phases of Waterfall but splits them into planning, risk assessment, and prototype building, making it a hybrid of sorts that works especially well in these types of projects.

Agile

In our book, and we might be a little biased, Agile is the methodology that developers favor the most out of all the methodologies out there. 

Famous for its iterative approach to software development that offers rapid-fire progress, Agile is a framework that fosters highly collaborative environments between all the teams involved in a project.

It’s dynamic, adaptive, flexible, lightweight, and extremely responsive, working in sprints with a defined time period to complete small and highly manageable tasks, thus reducing the time in which software goes live. Through and through, Agile is an advocate of adaptive planning, evolutionary development, continuous improvement, responsiveness, flexibility, and quick delivery.

Kanban, Scrum, or Agile: read more to see which model works better in which case.

Iterative and incremental

The iterative and incremental SDLC model does its name honor. This model is kicked off with a small set of requirements which is then enhanced iteratively with evolving versions until you reach a final product that’s ready to be implemented and deployed. The iterative and incremental model is the answer to Waterfall’s many faults; for example, the iterative life cycle starts by specifying and implementing only a portion of the software, which is then reviewed to dictate which features will follow next.

In short, the iterative and incremental model works through multiple, repeated, and incremental cycles so developers can pinpoint which areas to improve based on previous deployments of the software.

V model

An extended arm of the Waterfall methodology, the v-model executes processes sequentially in an upward fashion, which in visual context resembles the letter V.  Some refer to the v-model as the verification and validation model thanks to its foundation of testing phases for each development phase. In short, every piece of software development is associated with a testing phase.

One thing to note about the v-model is that no phase can start until the previous one is completed including a corresponding testing exercise. 

The beauty of software development is that methodologies can be combined to create a hybrid solution that distinctively addresses the unique needs of a project. Usually, organizations prefer to trust system analysts to make that decision and select the best-suited methodology or combination of models. 

Next, we’re going to explore the roles of a system analyst and an information system architect to better understand what each role entails, how they uphold the standards of the SDLC, and the valuable skills they need to have as they are an integral part of any software project’s success.

SDLC Roles

System Analyst

System Analysts are knowledgeable in analysis and design techniques to solve business problems via information technology. Oftentimes, system analysts are tasked with identifying opportunity area gaps and generating organizational improvements to reach specific goals. Overall, the System Analyst is a professional who has strong interpersonal, technical, analytical, and management skills.

The System Analyst works on high-level system reviews to assess if systems and infrastructures operate effectively and efficiently. System analysts research problems, find or develop solutions, recommend a course of action, communicate and coordinate with stakeholders, choose resources, and design action plans to reach a goal and meet predefined requirements. They are experts at studying a system, process, or procedure to come up with the best solutions.

Ideally, System Analysts are highly skilled and knowledgeable in multiple operating systems, hardware configurations, programming languages, and software and hardware platforms. They are usually involved from the beginning stages of a project and up until the post-evaluation review of the solution. In short, this type of professional is known for being able to help transform requirements into technical design specifications by understanding and determining how to solve a problem with a diverse selection of platforms, protocols, software, hardware, and communication outlets.

Information System Architect

The Information System Architect architects the project across its life cycle; In short, this professional designs the software architecture and defines the main interfaces and key elements of the information system as a whole.

Within the SDLC framework, the Information System Architect takes on highly active roles during the planning, analysis, and design phases, and acts as a companion role in all other phases of development. 

The Information System Architect is responsible for selecting the high-level tech stack and component structure of the future solution. Once the technologies and components are selected, the architect proceeds to determine the implementation patterns and components to then create a thorough description of the interaction protocols, programming languages, frameworks, data storage systems, and cloud systems. 

In the later stages of the SDLC, the architect systematically reviews the system’s requirements, maintains close communication with the client, supervises the architectural aspects of the system at all stages of implementation and testing, and modulates any reengineering or refactoring efforts of the system.

Project Manager

As a multilayered role, the Project Manager is in charge of managing and overseeing the end-to-end SDLC effort, allocating resources and handling other operational tasks such as financials, planning, and more. They are typically tasked with selecting the right project management methodology with full ownership of the methodology components. 

Project managers are also responsible for keeping stakeholders in the loop of everything that’s happening with a project by engaging with them regularly and keeping communication channels open and flowing. This professional is also tasked with developing and employing best practices and standards for project documentation as well as comprehensive documentation of requirements. Additionally, project managers must also carefully evaluate the risks of the project across every phase and craft contingency plans to mitigate or reduce risks as much as possible.

Software Developer

Integral to the success of any SDLC project, the developer writes project code and integrates system elements into a cohesive end product. Developers are responsible for developing the system architecture with assistance from the System Architect, evaluating and carefully selecting the right tech stack based on unique project needs. 

Developers help develop scripts for automated testing and fix any system flaws or defects as testers identify them.

Tester (QA)

The project is as good as it is thoroughly tested, which is why the tester's role is critical in any SDLC effort. Testers test the software and validate that it’s behaving as intended as well as approving the beta version release once it’s properly tested and retested.

In the first SDLC phases, testers design and develop a test plan with a specific set of acceptance tests based on which decisions will determine the product’s transition to the next development phase and the criteria for defects in subsequent testing iterations. 

Testers typically use both black and white box testing, and take an active role when writing QA automation scripts with developers.

DevOps Engineer

DevOps engineers are IT professionals who work side-by-side with developers and other IT personnel to look after and guide code releases and deployments. DevOps professionals play a key role in the SDLC effort, especially in the planning and system operation components. 

Early in the project, DevOps professionals engage in project planning in concert with the system architect and system analyst to help select the optimal CI/C tools and cloud-based solutions that meet the unique needs of the information system. DevOps professionals are acutely aware of project requirements and use them as the foundation behind every technology, architecture, and tool selection. 

DevOps professionals also work side-by-side with developers and testers to help monitor the end product across its cloud infrastructure, scalability, and load. This unique role frequently moves several times throughout SDLC phases, formulating requirements for the system along the way for the next development cycle, and upholding SDLC standards.

Conclusion

Time and again, it’s been proven that projects not only benefit but thrive by following a standardized set of steps to achieve a final result. Cue the Software Development Life Cycle which allows the team to work on manageable phases until the project is released. By doing so, teams establish a systematic fashion to go about creating new solutions to existing problems in a controlled and standardized manner. 

Before embarking on a new project, it’s important to identify how the SDLC will cover and satisfy the overall requirements to deliver the best results. Next, you can select the best SDLC methodology or a combination of methodologies to help you address the best approach to execute the SDLC. 

At Svitla Systems, we have expert teams of specialists who are knowledgeable in all the major SDLC methodologies, as well as the latest and most successful methods to help you build a powerful information system.