Typically, the software development process is lengthy and time-consuming. In contrast, project managers and system analysts may make better use of the software development life cycle to define information systems or software products as well as plan, create, test, and finally deploy them with higher regularity, efficiency, and overall quality.

In this article, we will go through the definition of the Software Development Life Cycle. We will also see different SDLC phases with examples.

What Is Software Development Life Cycle (SDLC)

Let us see SDLC meaning. It is possible to express the software life cycle in both visual and diagrammatic form using a software life cycle model (also known as a process model). A life cycle model depicts all of the processes that are necessary to move a software product through the various phases of its life cycle. 

It also reflects the organizational structure within which these procedures are to be carried out. In other words, a life cycle model depicts the numerous operations carried out on a software product from the time of its conception until the time of its decommissioning. A variety of life cycle models may be used to divide important development tasks into stages in a variety of ways. 

As a result, regardless of which life cycle model is used, the key activities are included in all life cycle models, even if the actions may be carried out in a different sequence in various life cycle models. During every stage of the life cycle, more than one activity may be carried out at the same time.

Need For Secure Software Development Life Cycle

The development team must first select which life cycle model is most appropriate for a certain strategy and then adhere to that model. The development of a software product would not be conducted in a methodical and disciplined way if a precise life cycle model were not used throughout the process. 

When a software product is being developed by a team, there must be a clear understanding among team members as to when and what should be done. Otherwise, it would indicate anarchy and the collapse of the endeavor. An example might be used to define the nature of the issue. 

Consider the following scenario: a software development problem is broken into many sections, each of which is allocated to a different team member. Consider the following scenario: the team representative is given complete autonomy to develop the duties that have been allocated to them in any manner they see fit. 

One representative may likely begin writing the code for his or her portion first, while another may opt to prepare the test documentation first, and yet another engineer may begin with the design phase of the tasks that have been given to him or her. The use of this strategy would be one of the most effective ways to ensure project failure. 

A software life cycle model explains the criteria for entering and exiting each step of the software development process. A phase may only begin if all of the stage-entry conditions for that phase have been met. As a result, without a software life cycle model, it is impossible to determine the criteria for entering and exiting a stage. 

Software project managers will find it difficult to keep track of the development of their projects if they do not use software life cycle models.

SDLC Phases

Every SDLC goes through these phases:

  • Planning & Requirement Gathering

The requirement analysis step of the software development life cycle (SDLC) is the most critical and basic. Customer, sales department, market surveys, and domain specialists in the sector provide input into this process, which is carried out by the team’s top members of staff. 

Once this information has been collected, it will be utilised to establish the main project strategy as well as perform a product feasibility analysis in the areas of economics, operational efficiency, and technical feasibility. During the planning stage, it is also necessary to consider the need for quality assurance and to identify the risks that may be connected with the project. 

The conclusion of the technical feasibility study will be the definition of the numerous technical methods that may be used to effectively execute the project with the least amount of risk possible.

  • Defining Requirements

Following completion of the requirement analysis, the next stage is to explicitly describe and record the product needs, which must then be accepted by the customer or market analysts before moving further. During the project life cycle, this is accomplished via the use of an SRS (Software Requirement Specification) document, which contains all of the product requirements that will be planned and produced.

  • Designing The Product Architecture

In order to come up with the ideal architecture for the product that is being produced, SRS is used as a reference by product architects. Based on the requirements described in the SRS, often more than one design approach for the product architecture is offered and documented in a DDS – Design Document Specification – document called the Design Document Specification.

This DDS is evaluated by all of the major stakeholders, and the optimum design approach for the product is chosen based on a variety of characteristics like as risk assessment, product robustness, design modularity, budget and schedule restrictions.

Using a design approach, it is possible to explicitly specify all of the architectural modules of a product, as well as the depiction of communication and data flow with the external and third-party modules (if any). The internal design of all modules of the proposed architecture should be thoroughly documented in DDS, down to the most minute of the details.

  • Development Of The Product

The real creation and construction of the product take place during this stage of the SDLC. During this step, the programming code is produced in accordance with DDS. If the design is completed in a precise and orderly way, code generation may be completed without a lot of difficulties.

Developers must adhere to the coding standards established by their business, and programming tools such as compilers, interpreters, debuggers, and other similar tools are used to create the code in question. Coding is done using a variety of high-level programming languages, including C, C++, Pascal, Java, and PHP, among others. 

The programming language is selected in accordance with the kind of software that is being produced.

  • Testing Phase

This stage is frequently a subset of all the stages since, in contemporary SDLC models, testing activities are primarily engaged in all of the phases of the SDLC process. Product faults are reported, tracked, repaired, and retested in this stage until the product meets the quality requirements stated in the SRS. 

This stage does not include any other phases of the product’s development or manufacturing.

  • Product Launch & Maintenance

Once the product has been thoroughly tested and is ready for deployment, it is officially launched in the relevant market. Product deployment may take place in stages, depending on the business strategy of the organization in question. It is possible that the product will be introduced in a restricted market sector and evaluated in a real-world business context initially (UAT- User acceptance testing).

The product may then be launched in its current form or with proposed improvements in the targeted market niche, depending on the input received. After a product is introduced to the market, it is maintained for the benefit of the current client base.

SDLC Phases
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These were Software Development Life Cycle phases. Now we will see different Software Development Life Cycle models.

Different Software Development Life Cycle Models

Now as we know SDLC phases, let us see SDLC models:

  • Waterfall Model Of Software Development Life cycle

The waterfall model is the most widely used software development lifecycle, model. The whole software development process is separated into many stages according to this technique of working. With the waterfall model, development is seen as flowing smoothly downhill through the processes of requirements analysis, design, implementation, testing, integration, and maintenance.

It is important to note that the linear ordering of activities has certain major repercussions. First and foremost, certification procedures must be used after each stage to distinguish between the end of one phase and the beginning of the next. 

The term “verification and validation” refers to the process of checking whether the output of a stage is consistent with its input (which is the output of the previous step) and if the output of a stage is compatible with the overall requirements of the system.

Waterfall Model Of Software Development Life cycle

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  • RAD Model Of Software Development Life Cycle

In contrast to the waterfall paradigm, the RAD (Rapid Application Development) methodology is built on prototyping and iterative development, with no explicit planning required. Writing software entails the planning that is necessary to create the final result, and this is done throughout the writing process.

Early user testing of prototypes utilizing an iterative approach, reuse of existing prototypes (components), continuous integration, and quick delivery are the primary goals of rapid application development. Workshops and focus groups are used to obtain client needs. When it comes to software development, fast application development is a process that relies on minimum preparation in favor of quick prototyping.

Prototypes are a functioning model of a component of a product that is functionally equal to that component. According to the RAD approach, functional modules are built-in parallel as prototypes, which are then combined to form the final product, resulting in quicker product delivery. 

Because there is no formal preplanning, it is much simpler to integrate modifications into the development process as they occur throughout the process. A rapid application development (RAD) project follows an iterative and incremental paradigm, with small teams made up of developers, domain experts, client representatives, and other IT resources working on a component or prototype progressively.

The most critical component of ensuring that this approach is effective in ensuring that the prototypes created are reusable.

RAD Model Of Software Development Life Cycle

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  • Spiral Model Of Software Development Life Cycle

The spiral model is a process model that is driven by risk. A waterfall, incremental, waterfall and other process models are included in this SDLC model, which assists the organization in adopting components of one or more of these models. In design and development, the spiral approach is a mix of fast prototyping and concurrent operations in both design and development.

To begin a cycle in the spiral, identify your goals, the many choices that are available to you for accomplishing your goals, and any limitations that you may be subjected to. The first quarter of the cycle is represented by the number 1. (upper-left quadrant). The next phase in the cycle is to compare and contrast the various possibilities in light of the goals and restrictions. 

At this stage, the emphasis of assessment is on the perception of risk associated with the project. The next phase is to devise solutions for dealing with uncertainties and hazards that have been identified. Benchmarking, simulation, and prototyping are examples of activities that may be included in this stage.

Spiral Model Of Software Development Life Cycle

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  • V-Model Of Software Development Life Cycle

Testing and development are scheduled in simultaneously under this form of SDLC model, which is similar to the one used by Microsoft. As a result, there are verification stages on one side of the process and a validation phase on the other. The Coding step is when the V-Model joins.

V-Model Of Software Development Life Cycle

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  • Agile Software Development Life Cycle Model

Iterative and incremental process models are combined in the Agile Software Development Life Cycle model, with the emphasis on process flexibility and customer satisfaction via the delivery of a functional software product at a faster pace. Agile methods divide a product into tiny incremental builds, which are then combined. Iterations of these builds are available. 

In most cases, each repetition lasts between one and three weeks in duration. Each project, according to the Agile model, must be approached differently, and current methodologies must be adjusted to better meet the goals of the project at hand. To provide particular features for a release, the tasks in Agile are separated into time boxes (short periods).

The technique is iterative, with each iteration resulting in the delivery of a functional software build. For features, each build is incremental, with the final version including all of the features specified by the client.

Agile Software Development Life Cycle Model

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  • Big Bang model Of Software Development Life Cycle

This model entails concentrating all available resources on software development and coding, with little or no consideration given to other aspects of the project. It is understood and executed as needs are identified. The programme may or may not need a full rewrite if any modifications are necessary.

In addition to being suitable for small projects with one or two developers working collaboratively, this approach may also be used for academic or practise projects. For a product when the needs are not fully known and the ultimate release date is not specified, this is a suitable model to use.

Big Bang model Of Software Development Life Cycle

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  • Iterative Model Of Software Development Life Cycle

The iterative process begins with modest implementation of a subset of the software requirements and progresses via many iterative enhancements of those versions until the whole system is realized. Design adjustments are performed and new functional capabilities are introduced with each iteration. 

The underlying concept of this strategy is to construct a system via repeated cycles (iterative development) and in smaller sections at a time, rather than all at once (incremental).

Iterative Model Of Software Development Life Cycle

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Software Development Life Cycle: Helping To Build Successful Products

When building IT projects, Software Development Life Cycle (SDLC) is often employed. To ensure that all stages of the development process are completed on time and in the correct order, software development managers will use SDLCs to outline various development stages, ensure that everyone completes stages on time and in the correct order, and ensure that the project is delivered as quickly and bug-free as possible.