Software Development Lifecycle (SDLC) Beginners Guide

Software development Life cycle (SDLC) is a process of producing high-quality software at the lowest cost and in possibly less time. Generally, SDLC has well-tested and ready-to-use phases which provide an organization to help in creating high-quality software. ISO/IEC 12207 is an international standard of software life cycle process. This standard defines all the tasks which need to develop and maintain software. SDLC targets to produce high-quality software by meeting the expectations of clients within the time limit and in budget. It is made up of a plan which describes how to develop, maintain, alter, and improve the software.

Why we need SDLC

Basically, SDLC is a method with the process, which helps in creating high-quality software. By this you can understand the whole criteria of producing effective software, that’s why SDLC is important. Without SDLC you can’t create a standard software because it gives a standard way to produce an effective and efficient software that will run in the market with client expectations which will help him in managing his part of work. With time we update the software as per customer feedbacks to get a better result which is also a part of SDLC.

Benefits of the Software Development Lifecycle

  • Forms the base for project planning.
  • Helps to estimate cost and time.
  • It gives the clarity of the project and the development process.
  • Enhance the speed and accuracy of development progress.
  • Minimizes the risks and maintenance during the project.
  • Its given standard improves client relations.
  • SDLC implement checks to ensure that the software is well tested before being installed in greater source code
  • Developers can’t move to the next step until the prior one is completed by SDLC.

What are the SDLC phases

Analyze:-  This is the initial stage to produce software. Before creating software we gather information from the client which is required to create the software as what will be nature of software, facilities, etc. The collected data will make a sense of exactly what kind of software the client wants which will help us in making a plan and collecting the correct resources.

Planning:-  Planning is the second phase of SDLC. Without a clear vision, it is hard to plan and gather everything related to the project goals. Planning is the one which will decide what will be the timeline of each phase and estimation of cost, and challenges involved as well as the effectiveness and exactly what resources we need to produce a software.

Designing:-  Designing is the next part after planning to look into it as it is an important part to give an identity to software, like how it will be looking like, what features will be given at what place, what be the symbol kind of things which will make it unique and easy to use for users and to meet the client requirements.

Development:- The actual stage of producing software starts from here. The development process may involve teams of people, new technologies, and unexpected challenges. Developers must follow the coding guidelines defined by the programming tools like compilers, interpreters, debuggers, etc. are used to generate the code. Different high-level programming languages such as C, C++, Pascal, Java, and PHP are used for coding. The programming language is chosen with respect to the type of software that will be developed.

Testing:- In this phase of work, software development is done and ready to test to assure quality. Testing or quality assurance ensures the solutions implemented, pass the standard for quality and performance. It can involve end-to-end tests, identifying bugs or defects in the software. This stage refers to the testing only stage of the software where product defects are tracked, fixed, and reported until the product comes into the quality standards defined in the SRS.
Deployment:- After finishing the testing stage it comes to officially deploy the software in the market to get used by the customers. This is the final stage of bringing the software in the market to check whether the created software is getting liked and useful by the customers as per expectations or not. The product may first be released in a limited area and tested in a real business environment. Then based on the feedback, the product might be released as it is or with suggested enhancements in the targeting market area.

Monitoring:- After officially releasing the software in the market, it comes under monitoring to check how its performing and what changes and enhancement it needs, which will be solved by the giving update. In this stage, the software is operationalized to ensure there are no issues or incidents related to the deployment. Sometimes to give the update we have got to down the server but in some cases, we can give the update without making the server down (as being live in market/ properly working). This stage can involve reviewing, understanding, and monitoring network settings, infrastructure configurations, and performance of application services.

Software Development Life Cycle Models

Waterfall Model:-

A little too old and harsh model is the Waterfall model. It is one of the old-fashioned SDLC models that is not much preferred in the modern software development ecosystem.

The reason it is not favored much is that it runs on a very inflexible structure conditioning that the entire set of requirements should be laid down from the very beginning of a project. This limits the freedom and flexibility of the actual design and development of software.

After completing the development, the product goes through the test for meeting its initial requirements. If it is not good enough, it is to be restructured, which is a lot of work.

Usually, software development companies resist dealing with Waterfall though it still seems to be an effective model for the handful of projects.


RAD Model:-

The rapid Application Development (RAD) process is an adoption of the waterfall model. It aims to developing software in a short period. The RAD model is based on prototyping and iterative development with no specific planning involved. The process of writing the software itself involves the required planning for developing the product. The RAD model is based on the concept that a better system can be developed in less time by using focus groups to collect system requirements

  • Business Modeling
  • Data Modeling
  • Process Modeling
  • Application Generation
  • Testing and Turnover

 Spiral Model:-

The spiral model is a risk-based process model. This SDLC model helps the group to adopt elements of one or more process models like waterfall, incremental, etc. The spiral technique is a combination of fast prototyping and concurrency in design and development activities. The following will explain the typical uses of a Spiral Model –

  • When there is a budget compellable and risk evaluation is important.
  • For intermediate to high-risk projects.
  • Long-term project commitment because of probable changes to economic priorities as the requirements change with time.
  • Customer is not sure of their requirements which is ordinarily the case.
  • Requirements are complicated and need evaluation to get clarity.
  • Some changes are expected in the product during the development cycle.


V-Model :-

In this model execution of processes happens in a sequential method in a ‘V-shape’. It is also known as ‘Verification and Validation model’. The V-Model is an Expansion of the waterfall model and is based on the association of a testing phase for each related development stage. That means for every single phase in the development cycle, there is a directly associated testing stage. This is a disciplined model and the next phase starts only after completion of the previous phase.

Incremental Model :-

The incremental model is not a distinct model. It is radically a series of waterfall cycles. The requirements are divided into groups at the initial stage of the project. For each group, the SDLC model is adhered to develop software. The SDLC process repeats with each release adding more functionality till all requirements are met.

use of  Incremental Model:-

  • When the requirements are much superior.
  • A project has a lengthy development program.
  • When Software team are not well skilful or trained.
  • When the customer demands an immediate release of the product.
  • You can develop precedence requirements first.


Agile Model :-  

The agile model is a model which promotes continuous interaction of development and testing during the SDLC process of any project. The agile model is a combination of iterative and incremental process models with aims on process and customer satisfaction by continuous delivery of working software products. Agile Methods have divided the product into small incremental builds. These builds are issued in iterations. Each iteration lasts from typically one to three weeks. Every iteration involves cross-functional teams working together on various areas like

  • Planning
  • Requirements Analysis
  • Design
  • Coding
  • Unit Testing and
  • Acceptance Testing.

At the end of the iteration, a functional product is displayed to the customer.

Iterative Model :-

In the iterative model, the iterative process starts with the implementation of a small set of software requirements, makes  enhancements in the evolving versions till the complete system is implemented and ready to deploy on the market. In this model development of the life cycle doesn’t start with full requirements, instead, it begins with the implementation of just a part of the software, which will be reviewed to identify further requirements later. This process is repeated till the new version of the software is produced at the end.

Big bang model :- 

The big bang model comprises focusing all types of possible resources in software development and coding with little bit or no planning. This model works best for small projects with the smaller size development team who works together. It is useful in academic software projects as well. It is also an ideal model where requirements are either unknown or a final release date is not provided.

Advantages of the Big Bang Model

  • This is very easy to use model
  • Little bit or no planning required
  • Easy to handle
  • Very few resources are needed
  • provides flexibility to developers

Disadvantages of the Big Bang Model

  • Very High risk & uncertainty.
  • Not a good model for difficult and object-oriented projects.
  • Poor model for long-term and ongoing projects.
  • Can become very expensive if requirements are not properly understood.


Prototype Model :-

The prototype model starts with the gathering of required information to start the development process. In this the developer meets the client, understand the purpose of software and identify the actual requirement. Then a quick design is created, focused on each aspect of the software which will be visible to the user. Then it goes ahead with the development of prototype, customer checks and try to identify if any modification needs to be done. In this step, looping occurs and better versions of prototype are created. It continuously happens being in touch with client to show him if any further requirements needs to be done.  This process remains continue till the user is satisfied. Once the user is satisfied, the prototype is converted into the actual system to deploy in market.

DevOps:-  Let’s understand. In the agile Model, both Development and testing activities were concurrent, unlike the waterfall model. It was lost on practices that didn’t come up to speed with agile practices. Due to lack of collaborations between developers ad the operations team, slow down the development process and releases. Then software companies started realizing the need for better collaboration between teams and faster delivery of software. It gave birth to the DevOps approach. DevOps enabled fast software delivery with minimum problems to fix and faster resolution of problems. The term DevOps is deprived of two words development and operations. DevOps is a practice that allows a single team to manage the whole application development life cycle, i.e. development, testing, deployment, etc. The aim of DevOps is to shorten the development life cycle. DevOps is a software development approach that helps in producing high-quality software with reliability and in less time. DevOps is a software development method that aims at communication, integration, and collaboration between IT professionals to enable continuous deployment of products.

Which SDLC Model is Best

As far I have understood, DevOps is the best model in today’s software ecosystem which provides a better development life cycle with high effectiveness and efficiency in work progress.  But it doesn’t mean rest models are not useful, they are also useful and still getting used by some organizations who feel that model is best in their work. DevOps is a practice of bringing development and operation teams together whereas, Agile refers to the continuous iterative approach, which aims at collaboration, customer feedback, small, and continuous releases. DevOps’ purpose is to manage end-to-end engineering processes. It helps in increasing an organization’s speed to deliver applications and services.  The agile purpose is to manage difficult projects. The agile development process divides the product into smaller pieces and integrates them for final testing. It can be implemented in many ways, including Scrum, XP, etc.


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