What is Software Development Life Cycle (SDLC)? Learn SDLC Phases, Processes, and Models

The software industry uses the Software Development Life Cycle process to develop, manufacture, and test high-quality software. Its goal is to produce high-quality software that satisfies customer requirements while staying on schedule and budget.

• The term "Software Development Life Cycle" refers to the SDLC process.
• It is also known as software development.
• The SDLC (software development life cycle) is a concept that specifies the actions that must be completed at each step of the software development cycle
• ISO/IEC 12207 is a global software life-cycle management standard. It aspires to be the ideal Model for all software development and maintenance aspects.

Software Development Life Cycle Process:

The software development life cycle (SDLC) is a process that ensures the quality and accuracy of software produced. The SDLC process attempts to provide high-quality software that satisfies the client's needs. The SDLC is a thorough method that outlines how to structure, produce, and maintain specific software used by  product development services company. Each level of the SDLC life cycle has its method and outputs that feed into the next stage.

Companies use the Software Development Life Cycle (SDLC) for developing software applications for many reasons:

• To show a planned approach to software development: The software development life cycle (SDLC) offers a plan for managing the software development process, ensuring all necessary steps are taken and the final product conforms with the specifications.
• Ensure a level of application quality by The testing and quality assurance phases of the SDLC
• give assurance that the software is error-free and conforms with the requirements.
• Limiting expenses and risks: By identifying and controlling risks early in the development cycle, companies may lessen costs and the effect of any problems that do surface.
• To improve communication and collaboration: The SDLC guarantees that customers, end users, and developers are all involved in the creation process and that their needs are fulfilled.
• To increase output: The SDLC helps organizations make the most use of their resources by optimizing the development process, potentially increasing productivity and efficiency.
• To improve the project's success: Implementing a well-defined SDLC methodology and using it to guide the team toward the project's goal would increase the likelihood of success.

Ultimately, the SDLC is a useful tool for product development company to utilize when creating software applications since it ensures that the finished product is of high caliber, complies with specifications, and is delivered on schedule and budget.

The development team must choose a life cycle model appropriate for a certain strategy and then adhere to it.

The creation of a software product would not be organized and disciplined without the use of a precise life cycle model. While developing a software product, team members must agree on when and what to do. Otherwise, it would be an indicator of chaos and project failure.

A software life cycle model describes the criteria for entering and leaving each phase. Only if the stage-entry requirements have been met can a phased start. So, detecting a stage's entrance and exit criteria is impossible without a software life cycle model. Without software life cycle models, it is difficult for project managers to track the project's progress.

SDLC Cycle:

A software life cycle model, often known as a process model, depicts the software life cycle in graphical and diagrammatic form. A life cycle model displays every operation needed to take a software product through each phase of its life cycle. It also includes the organizational structure within which these strategies will be implemented.

A life cycle model, in other words, represents the many activities performed on software from creation through retirement. The essential development activities may be scheduled according to phases in various life cycle models. So, no matter whether the life cycle model is used, all fundamental tasks are included, even if they may be carried out in different sequences depending on the model. You can carry out several activities at every stage of the life cycle.

SDLC Phases:

The product development services company and developers use the Software Development Life Cycle to discover effective strategies to reduce mistakes and utilize unique software solutions (SDLC).

We'll take you step-by-step through the stages that make up the software development life cycle process.

Requirement Gathering and Analysis:

To create a product that meets the consumer's needs, all necessary information is gathered from them during this phase. Any questions must be answered within this specific time.

The business analyst and project manager schedule a meeting with the client to obtain all the necessary information, such as what the customer wants to construct, who will be the end user and the product's purpose. When building a product, it is critical to have a basic grasp of it.

An analysis is conducted to determine whether the creation of a product is feasible once the requirements are gathered. A call is scheduled for additional discussion in the event of any uncertainty.

Once the need is fully understood, the SRS (Software Requirement Specification) document is made. The developers and the client should read this document carefully and save a copy for their records. Everything that has to be conceived and developed during the project life cycle is included. The primary categories of feasibility assessments done by  product development services company are as follows:

• Economic: Is it possible to accomplish the project within the allocated budget?
• Legal: Can we conduct this project by cyber legislation and other legal requirements?
• Operation viability: Are we able to provide operations that meet client expectations?
• Technical: We must determine whether the program will run on the existing computer system.
• Schedule: Determine if you can finish the project on time according to the timetable provided.

Design:

The system and software design documents are created at this phase following the requirement specification document, which clarifies the entire system's architecture. The design phase informs the model's subsequent phase. At this step, two different types of design papers are created:

High-Level Design (HLD):

The architecture of software packages is provided.

• Names and short descriptions of each module.
• A description of each module's features.
• Module dependencies and interface relationships.
• Identification of database tables and their essential components.
• Detailed architecture diagrams and technological information.

Low-Level Planning (LLD):

It explains how each feature and component of the product should operate.

• The logic of the modules' practical use.
• Tables in databases that detail kind and size.
• Full interface details.
• Focus on all dependence problems.
• An alphabetical list of errors.
• Each module's full inputs and outputs.

Implementation of Coding:

Production starts at this point, and the product is constructed. The DDS produces the programming code to maximize the effectiveness of the product's creation. The code is created by developers using various tools and programming languages. They are chosen following the requirements of the software being created. Some programming tools could include:

• Compilers
• Interpreters
• Debuggers


Programming languages include:

• C
• C++
• Pascal
• PHP
• Java


Important information regarding this phase:

• The SDLC model's longest phase is this one.
• The Front end, Middleware, and Back-end makeup this phase.
• Front-end: Coding development and SEO settings are completed.
• They link the front end with the back end in Middleware.
• A database is constructed in the back end.

Testing:

After the software is ready, it is installed in the testing set by the product development services company. The testing team begins by examining the system's general usability. That ensures the entire program functions in line with the client's requirements. Since the software is developed in phases, it is particularly crucial to this step of the SDLC. Combining these software components during testing enables one to evaluate how well each component works together and how well the software functions. At this phase, the QA and testing teams may identify defects or errors, which they report to developers. The development team fixed the problem and returned it to QA for another test. This procedure is repeated until the software is free of bugs, stable, and meets the system's business requirements.

Deployment:

The software is deployed in the production environment or undergoes UAT (User Acceptance Testing); depending on the customer's expectations, the system design can only start after the requirements have been firmly established. Following its requirements and level of complexity, the software can be installed manually or automatically.

While using UAT, a copy of the production environment is made, and the customer and developers test the software together. The consumer must approve the application to go online if they find it to be what they expected.

Maintenance: Each consumer uses software products differently since they have various demands; thus, certain problems can arise and must be fixed. At this maintenance stage, these client issues are resolved. The following 3 steps occur following the system's deployment and the customers' use of the developed system:

• Bug fixing - Certain circumstances not tested at all result in reported bugs.
• Improvement - Including some new features in the current software.
• Upgrade - Updating the software to newer versions of the software.

Teams may initially decide to deploy the product to a limited client base to reduce the maintenance that must be done. That can provide developers insight into how the product is doing and allow them to make last-minute changes before its official release.

Software Development Life Cycle Models:

The Software Development Life Cycle (SDLC) is a project management conceptual framework that specifies the processes of an information system development project, beginning with a feasibility assessment and ending with continuing support for the final product.

Many product development consulting firms have the life cycle models specified and designed in the development phase. To ensure success in the software development stage, each process model adheres to a set of steps that are specific to its type.

Waterfall Model: The waterfall model is the first Model used in the SDLC. The linear sequential Model is another name for it. The findings of one stage in this Model are used as input for the next phase. The following phase can begin once the previous phase has finished developing.

• Initially, requirements are gathered and analyzed. System design can only start after the requirements have been firmly established. In this example, the SRS document serves as both an input and an output for the System Design process.
• Throughout the system design and software architecture phases, documents are prepared as input for the implementation and coding phase.
• Coding is completed in the implementation phase, and the software created serves as the input for the following testing step.
• The produced code is rigorously checked throughout testing to find any software flaws. When a problem is fixed, it is retested and recorded in the defect tracking tool. Bug logging, retesting, and regression testing are all carried out until the software is complete. Upon client approval, the developed code is deployed into production.
• The developers are in charge of resolving any issues in the production environment that come under the scope of maintenance.

Application:

Every software generated is unique, depends on internal and external circumstances and must use a proper SDLC strategy. The following are some scenarios when the waterfall model is most useful:

• The requirements have been outlined, fixed, and meticulously documented
• The definition of the product is steady.
• Understanding technology means it is not dynamic.
• No unclear criteria exist.
• There are numerous resources available with the essential knowledge to support the product.
• The task is short.


Benefits of the waterfall model:

• The waterfall model is understandably straightforward, in which all steps are carried out sequentially.
• Because the deliverables for each phase are clearly defined, complexity is avoided, and project management by a product development services company is largely utilized.


Drawbacks of the waterfall model:

• The waterfall approach requires a lot of time and cannot be utilized for projects with a short lifespan since we cannot begin a new phase until the current phase is finished.
• This model assumes that the requirements are crystal clear throughout the requirement collection and analysis phase itself and that any modifications made during the following stages would increase expenses because they would need to be made during each step. As a result, it cannot be utilized for projects whose needs are ambiguous or whose requirements are dynamic.

V-Shaped Model:

The Verification and Validation Model is another name for the V-Model. With this methodology, development and testing go concurrently, and verification and validation go hand in hand. The only difference between the V and waterfall models is that testing and test planning begin earlier in the V-Model. The V-Model contains numerous Verification steps, each described in more detail below.

• Analysis of business requirements: The needs for the product are first grasped from the client's viewpoint at this phase of the development cycle. The consumer is extensively communicated with at this phase to ascertain his expectations and precise needs. Given that most consumers are unsure about their specific wants, this is a crucial task that has to be managed carefully. Although business requirements may be utilized as input for acceptance testing, the design planning for the acceptance test is completed at this stage.
• Creating systems: After fully understanding your product's requirements, it's time to design the entire system. The system design will include a thorough grasp of the hardware and communication configuration for the product being developed. Based on the system design, the system test plan is created. Doing this sooner makes more time for the actual test run.
• Construction design:In this stage, architectural specifications are comprehended and designed. The final decision is frequently reached after weighing various technological methods' technical and economic feasibility. Many functionalities are handled by modules further separated within the system design, often called High-Level Design (HLD).
  At this point, it is obvious and stated how data would be transferred and communicated inside the internal modules and with other systems. Here the knowledge may be used to develop and describe integration tests at this level.
• Device Design:This stage, known as Low-Level Design, specifies the internal details for all the system modules (LLD). The design must be compatible with the other system architecture modules and external systems. Unit testing is a crucial step in any development process since it enables the early elimination of most flaws and mistakes. These unit tests may now be created based on the internal module designs.

Coding Phase:

In the coding phase, the actual coding of the system components created during the design phase is done. The system and architectural requirements determine the most appropriate programming language.

The coding is done by a product development services company following the coding standards and rules. Before the final build is checked into the repository, the code undergoes several code reviews and is optimized for optimum performance.

Validation Phase:

These are detailed explanations of each Validation Phase of a V-Model.

• A unit test: The code is subjected to unit tests created during the module design process at this validation step. Unit testing, which is code-level testing, helps in the early bug-elimination phase but is imperfect.
• Integrity checks: Architectural design is connected to integration testing. Integration tests evaluate how well the system's internal parts get along and communicate
• System evaluation: System design and testing are closely related processes. System tests examine how the system functions and is connected to other systems. Most hardware and software compatibility problems can be found during the execution of this system test.
• Adoption testing: Acceptance testing involves evaluating the product in a user environment and connected to the business requirement analysis step. Compatibility problems with other systems in the user environment are discovered during acceptance tests. Moreover, it finds non-functional problems in the real user environment, such as load and performance flaws.

Application:

Although both models are sequential, the V-model application is similar to the waterfall model. When the project begins, the requirements must be crystal clear because it is typically expensive to go back and make adjustments. This technique is employed by software product development services as medical development is a highly controlled area. The situations listed below are best for using the V-Model application.

• The requirements are clearly stated, set, and well-documented.
• The definition of the product is steady.
• The project team has a solid understanding of technology and knows it is not dynamic.
• There aren't any unclear or vague criteria.
• The undertaking is brief.


Benefits of the V-Model:

• It is a simple model
• Smaller projects with stated requirements that freeze in the early stages benefit from the V-model approach.
• It is a systematic, disciplined approach that yields a high-quality end product.

Drawback of the V-Model:

• For current projects, a V-shaped model is not recommended.
• Further requirement changes would be prohibitively expensive.

Prototype Model:

The prototype model is a model in which the software prototype is created first. Comparing prototype models to the software reveals that they perform poorly and have limited functional capabilities. Prototypes are built with dummy functionality. That is a useful tool for figuring out what the customers want.

• Software prototypes are created before the final product to obtain useful user input.
• After considering user feedback, the client once more examines the prototype. This procedure continues till the customer accepts the model.
• After gathering requirements, a rapid design is made, and a prototype is developed before being delivered to the customer for review.

The prototype is modified in response to client comments and the clarified need, then represented to the client for review. The customer must accept the prototype before one develops a simple program. The Waterfall model is used to build the actual software.

Benefits of a Prototype Model:

• Development costs and time are reduced when flaws are discovered considerably sooner using prototype models.
• A change in need, a missing feature, or a lack of functionality can all be found during the assessment process and included in the finalized prototype.
• A customer's involvement from the beginning clears up any misunderstandings about the functionality's requirements.

Drawbacks of the prototype model:

Due to their involvement at every stage of the process, the customer can change the specifications for the final product, which complicates the scope and may increase the production time.

Spiral Model: Iterative and prototype approaches are part of the Spiral Model. The iterations follow the Spiral Model's phases. The innermost loop in the model is for requirement collecting and analysis, followed by planning, risk analysis, development, and assessment. The loops in the model reflect the phases of the SDLC process used by the software product development services. The second cycle includes designing, then comes testing and implementation. Four phases make up the Spiral Model:

• Planning: Gathering requirements is a part of the planning step, during which the client is asked for all the necessary information, which is recorded. The writing of the software requirement specification document marks the start of the next step.
• Risk assessment: The best solution for the risks involved in this phase is chosen, and analysis is completed by creating the prototype. As an illustration, there is a chance that the data access rate from a remote database will be excessively sluggish. Building a prototype of the data access subsystem will eliminate the danger.
• Engineering: Coding and testing are completed when the risk analysis is completed.
• Assessment: The client assesses the system created and makes plans for the following iteration.

Benefits of the spiral Model:

• Risk analysis makes considerable use of the prototype models.
• Any functional alterations or enhancements that might be included in the subsequent iteration.

Drawbacks of the Spiral Model:

• The spiral model is best suited for large projects alone.
• The cost may be high because it may take multiple iterations and a long time to achieve the desired outcome.

Iterative Incremental Model:

The product is divided into manageable pieces using the iterative, incremental methodology. For instance, a feature that creates the iteration throughout is chosen and put into practice. Phases such as requirement analysis, design, coding, and testing are completed throughout each iteration. After each iteration, a product is valued and forwarded to the client for evaluation and feedback by product development services. The newly integrated functionality is merged with consumer feedback in the subsequent iteration. Hence as iterations lead, the product gains or has add-ins, and the end version has all the required features.

Iterative Incremental Model Phases:

• Inception phase: The project's requirements and scope are defined.
• Elaboration phase: The functional architecture of a product is supplied during the elaboration phase. That also satisfies non-functional needs and addresses risks identified during the inception phase.
• Construction phase: During the construction phase, the architecture is filled with code that is ready for deployment and is produced through functional requirement analysis, design, implementation, and testing.
• Transition phase: The product is deployed in the Production environment during the Transition Phase.

Iterative Model - Application

Iterative and incremental development has several specialized uses in the software business, just like other SDLC models. The circumstances listed below are where this model is most frequently used by  software product development services:

• The system's requirements are well-defined and comprehended.
• Key criteria must be specified; however, certain proposed functionality or improvements may change.
• The market limitation has a timeframe.
• The development team uses and learns new technology while working on the project.
• Resources with the required skill sets are not readily available and will only be employed under a contract for certain iterations
• Several high-risk elements and objectives might alter in the future.

Iterative and incremental modeling's benefits include the following:

• Each requirement modification is possible and won't cost anything because one may include a new need following iteration.
• The iterations examine and identify risk.
• Early defect detection is achieved.
• The product is simple to manage because it has been broken into tiny pieces.

The iterative and incremental model has certain drawbacks:

• A complete grasp of a product is necessary to tear down and develop progressively.

Big Bang Model: The Big Bang Model has no established procedure. Input and output consist of money and labor; the result is a created good that may or may not be what the client requires.

The Big Bang Model doesn't need a lot of schedule or planning. The developer analyzes the requirements, writes the code, and creates the product per his knowledge. This strategy is only applied to modest projects. The lack of rigorous testing and a testing team might spell disaster for the project.

Benefits of the Big Bang Model:

• It is a very basic model.
• There is less need for scheduling and planning.
• The developer has the freedom to create their program.

Drawbacks of the Big Bang Model:

• You cannot handle large, ongoing, sophisticated projects with big-bang models.
• High uncertainty and danger.

Agile Model:

The incremental and iterative models are combined to create the agile Model through software product development services. This model gives less emphasis on requirements while creating a product and more attention on flexibility.

With Agile, a product is broken down into manageable incremental builds. It is not entirely produced in a single session. With each build, more features are added. The future upgrade enhances existing functions.

Sprints are the term used for iterations in agile. A sprint lasts two to four weeks. Each sprint ends with the product owner verifying it before it is provided to the client with their permission. Consumer input is used to make improvements, and the following sprint will focus on his recommendations and enhancements. Each sprint includes testing to reduce the possibility of any failures.

Benefits of the Agile Model

• That gives you greater freedom to adjust to the changes.
• The new functionality is simple to implement.
• Customer satisfaction because we consider their feedback and suggestions at every stage.

Disadvantages of the Agile Model:

• Inadequate documentation.
• Agile requires highly qualified and experienced personnel.
• The project would fail if the customer were unsure exactly how they wanted the final result.

Conclusion: Using an appropriate life cycle is essential for a project to be successfully finished by  software product development services. In turn, this facilitates management. There are benefits and drawbacks to each software development life cycle model. The elements like need (whether it is obvious or confusing), system complexity, project size, cost, talent limitation, etc., may help establish the optimal model for every project.

Spiral and Agile models, for instance, are ideal to utilize when a need is uncertain since they may readily accommodate necessary adjustments at any stage. All other SDLC models are built only on the waterfall model, which is a fundamental model.