A lot of people talk about software development methodologies. More often than we’d like, these methodologies go forgotten or are not employed to their full extent. Other times, people get caught up in trying to decide which is the best software development methodology for their unique needs.

But if one thing is true is that it’s better to have some form of methodology than a complete lack of it. Any software development methodology for information systems will have a foundation on the Software Development Life Cycle (SDLC), whether it is the classic Waterfall model, Evolutionary, Agile SCRUM, Kanban, or other new models. SDLC will always be present, the only question is in what time frame and in what variation.

Let’s take a look at the stages of this life cycle and see how they affect the development process.

What is SDLC?

The Software Development Life Cycle consists of seven main phases that any software system goes through. Keep in mind that all systems are different in terms of complexity, required components, and expected functionality.

The product life cycle describes the process of building information systems in a very thoughtful, structured, and methodical way, repeating each stage of the product life cycle. The systems development life cycle was proposed in the early 1960s for the development of large-scale, functional business systems. Information system’s activity was based on heavy data processing and processing of arrays of routine calculations.

The Structured Systems Analysis and Design Method (SSADM) developed for the UK Government Commerce Authority in the 1980s was based in part on SDLC. Traditional approaches to developing systems are reconfigured based on the environment and developers’ capabilities to maximize the satisfaction of future users of the system.

Why SDLC matters

Before starting software development, it is very important to understand the full information system development cycle and to imagine exactly what types of activities will be performed at each stage.

It can be compared to building a large boat, where every stage of its construction is planned, from launching, operation in the ocean, scheduled maintenance, and refitting.

While it is possible to build a very large sea vessel without any sort of methodology, chances are that it will not go smoothly and it will probably not work properly. This happens in software as well - you can write a very robust system but may not be able to configure it to work successfully for real users.

The best practice is always to plan all stages of the SDLC correctly and the whole system will work as intended.

Stage 1. Planning

The planning phase is the most critical step in creating a successful system. During this phase, you determine what you want to do and what tasks to solve.

Software requirements engineering is the discipline of analyzing and documenting software requirements, which consists of transforming the requirements of the system proposed by the customer into a description of software requirements and their validation.

• Software Requirements consists of the following sections:
• Requirement Engineering
• Requirement Elicitation
• Requirement Analysis
• Requirement Specification
• Requirement Validation
• Requirement Management

Requirements identification is the process of extracting information from various sources (contracts, analysts' materials on the composition of system tasks and functions, etc.), conducting technical activities (interviews, collecting proposals, etc.) to form individual requirements for the product and the development process.

As a result of this phase, we will obtain a description of the requirements for the future system.

Stage 2. Analysis.

It is necessary to define and document the requirements of the end-user of the system - what are their expectations and how to fulfill them. In addition, a feasibility study is made for the project, which clarifies whether the project is organizationally, economically, legally, and technologically feasible.

At present, more than 50 object-oriented methods have been developed, which are used as mechanisms for developing object models and building software systems based on them. The main concept of these methods is the object, as well as other definitions of the elements of the subject area that is created.

The method of object-oriented modeling involves the sequential implementation of two stages: object-oriented analysis and object-oriented design.

Object analysis - the study of objects of the subject area. The subject area includes those objects and relationships between them that are essential in describing the requirements and conditions in solving problems. In the object-oriented design process, it’s important to determine software objects and the ways they will interact along with database schemas.

Requirements analysis – the process of studying the needs and goals of users, classification, and transformation into requirements for a system, hardware, and software, establishing and resolving conflicts between requirements, defining priorities, system boundaries, and principles of interaction with the operating environment.

Specification of software requirements – the process of the formalized description of functional and non-functional requirements, and requirements for quality characteristics in accordance with the quality standard ISO/IEC 9126, which will be developed on the processes of SDLC software.

As a result of completing this phase, we will receive a complete set of clearly written system requirements.

Stage 3. Design.

The design phase begins after a good understanding of customer requirements has been achieved. This phase defines the system elements, components, security level, modules, architecture, various interfaces, and data types that the system operates on.

System design defines, in general terms, how the system will look and operate. Then, an extended, detailed design is made, taking into account all functional and technical requirements, both logically and physically.

This stage is very important and it is necessary to allow enough time to complete this phase with the required quality level. This will avoid wasting time in the following stages since it is much easier to fix errors at the design level than to redo the program code and reconfigure the systems on the servers.

System design is now usually described in the form of UML diagrams. This makes it possible to quickly and accurately describe all the necessary technical points. And developers are well aware of this approach since they have the necessary knowledge and can quickly and efficiently develop systems according to the developed design.

As a result of performing this phase, we will receive a description of the design of the system with components, relationships, and relationships between the constituent parts.

Stage 4. Development.

This phase follows a complete understanding of the system requirements and specifications. This is the process of system development when the system design is already fully completed and understandable to all parties.

In the system development lifecycle, this is where code is written. If the hardware part is available, the system includes the hardware part, and the development phase will include the configuration and adjustment of the hardware for specific requirements and functions.

In most projects, this part takes the most time and effort. To facilitate the task at this stage, various methodologies are used, including agile approaches and the decomposition of the software implementation of the information system.

At this stage, the system is ready for installation on test servers to test the functionality by the QA department.

As a result of this phase, we will have a functioning system ready for testing.

Stage 5. Testing and integration.

At this stage, various components and subsystems are assembled into one integral system. Then, the system is tested in various modes to analyze its state, behavior, and functioning.

Testing is becoming more and more important for customer satisfaction, and every year, the requirements for the quality of system performance are increasing.

Testing can be performed by real users or by a dedicated team of employees. Testing methodologies include white box testing, black box testing, automation, and manual testing, etc.

Testing can be manual or automated to make sure that results obtained from the system are consistent with those intended and desired. At this stage, all components of the information system are integrated into a single whole.

As a result of this phase, we will have a functioning and tested system, ready for use by customers.

Stage 6. Implementation.

After the testing phase, the information system should be transferred to the production environment for use by real users. This process involves the deployment of hardware and software, and the corresponding settings and configuration of all system components.

End-users may need training to become familiar with the system and know how to use it. The implementation phase can be very long, depending on the complexity of the system.

The implementation process itself may not take much time, but it is essential since an error in deploying the system further can have critical consequences for the entire information system, for example, loss of important data, failure of control systems, and so on.

As a result of this phase, we will get a functioning system on the customer's side, ready for use and prepared by a part of users who are familiar with the operation of the system.

Stage 7. Maintenance.

At this final stage, the system is fine-tuned as needed for certain improved parameters, for example, to improve performance, increase operational stability, reduce the risks of security breaches or data loss.

This phase ensures that the system remains up to date and usable by replacing old hardware, improving software, evaluating performance, and applying new updates. This is to ensure that it meets all required standards and includes the latest technology to protect against security threats.

During this phase, periodic technical support of the system is carried out to ensure that the system is not out of date. This includes replacing old equipment and continuously evaluating performance.

It also updates certain components to ensure that the system meets the required standards and the latest technology to avoid being exposed to current security threats.

Be clear about your backup and deployment options across a variety of cloud systems. Use containerization where necessary.

As a result of completing this phase, we will receive the necessary set of requirements for creating new functionality and then proceed to Phase 1.

How to Avoid Typical Mistakes in SDLC

Typical mistakes in SDLC development that should be strictly avoided:

• Not allocating enough time for the first stage so the customer can clearly and with great detail formulate the requirements for the system. This mistake affects all subsequent stages. To avoid this error, do not proceed to the following stages until the requirements are written out. 
• The analysis of the system was carried out in great detail in individual sectors, but there is no complete picture. The system does not function clearly. To avoid this situation, it is recommended to consider more possible use cases for the system.
• The system design is not worked out in sufficient detail and there is no basis to choose the right architecture. To avoid this situation, try using different kinds of UML diagrams. State diagrams and sequence diagrams will help a lot.
• Development of violated estimates per stage. To avoid this situation, set aside at least 20 percent of the reserve to cover risks.
• Adding new functionality during the testing stage. This will, most likely, break the whole system, sooner or later. To avoid this situation, first, complete one SDLC cycle, and on the next turn of the cycle, implement the new functionality.
• Forget to clearly prescribe instructions to deploy the system and the necessary actions to maintain operability during the implementation stage. To avoid this, request to write documentation on the necessary areas of work of all components.
• There is no user feedback during the maintenance phase. This will soon lead to big, difficult questions that will be difficult to resolve. Always be ready to go to the next round of SDLC to meet the needs of real users because the system is created for them.

Conclusion

After reviewing the seven main stages of the system development life cycle, we have identified an iterative process for each phase of the project. From project experience, it is necessary to maintain a high level of communication with the customer.

Oftentimes, prototypes can be used to help in large projects. We build the system with short iterations, and then in SDLC, we can close the first and last stages in a spiral for the foreseeable work area. We put together a large information system from pieces and account for all requirements during each iteration.

Many models of the development life cycle of information systems have been developed precisely on the basis of project management experience. At Svitla Systems, for each development team and for each client, our experienced PMs and team leaders make correct use of the SDLC methodology and employ the highest quality standards, which saves time, budget, and additional costs of correcting strategic errors.

In what exactly can Svitla Systems help with in terms of the SDLC?

• Develop projects for its customers from the ground up, taking into account the proper SDLC methodology
• Clearly align the design methodology with SDLC
• Strictly follow the Agile methodology and adhere to the SDLC plan at every iteration and milestone
• Help correct the existing SDLC, if any, or create a cycle description from scratch
• Audit the SDLC cycle in new projects and in projects that are ongoing

Our clients have successful development and an accurate, transparent understanding of the software development life cycle and high-quality software solutions.