Software Development Life Cycle (SDLC) Models & Phases

Software Development Life Cycle (SDLC) Methodologies & Phases in Software Engineering

The software development life cycle comes to the picture when you are going to prepare software with good quality. Because when we are implementing this life cycle structure into our software development, then we divide the complete process into two different stages.

Which helps us to get a quality product within a defined time. As we are following different phases, it helps us to find out where we need to improve. so that we can improve that point in the future iteration to increase productivity and also the quality of the software.

This is another continuous and posts up manual testing tutorial concept. In our last post, we have discussed in detail about what is quality assurance, what is quality control, and what are the difference between the QA and QC in details with a real-time example scenario.

If you look into the different stages of different methodology than they are of the same from one methodology to another. Sometimes those phases or stages occurred in order, or mixture together you may feel like some steps are occur in parallel.

The workflow of SDLC may be involved in a repetitive transaction or the iteration of phases to get the final software.

SDLC Phases

Following are the best practices and/or stages of SDLC to ensure that the process works in a smooth, efficient, and productive way:

• Requirement analysis
• Feasibility study
• Architecture design
• Software development
• Testing
• Deployment
• Maintenance

Requirement Analysis Phase

This is the initial stage of the SDLC model, which is a planning phase. In this phase, collaboration happens between taking orders from tech, business, and leadership minutes of the organization. and also some activities will be carried out in this stage which include

• Analyze and translate the business questions into engineering problems by considering various factors like cost, performance, functionality, and risk.
• Evaluate the broad scope of the project to identify the available resources
• Consider project opportunities and risk across the technical and business aspect of every decision choice in SDLC phases.

The output of a requirement analysis phase is project plans, schedule, cost estimation, and procurement requirements.

Feasibility Study In Software Engineering

Once the requirements are clearly understood, and the SRS ( software requirement specification) document is prepared. This document should be thoroughly followed by the developers and also review by the customer for future reference.

The feasibility study evaluates the following vital aspects, which are:

• Economic: where we are trying to find out, is it financially viable to invest in this project based on the available resources?
• Legal: what is the scope of Regulation and the organizational capacity to guarantee compliance?
• Operational: can you feel the requirement within the scope of definition according to the proposed operational framework and workflow.
• Technical: What is the availability of Technology and HR resources to support the SDLC process?
  Schedule: can we finish the project on time?

After going through with all the above vital points, the Executive Decision-makers should answer those a book keypoint questions and study them carefully before proceeding with the software design and implementation process.

If you are following the Waterfall model, then the output will be a document that lists all the requirements. But if you are following Asal methodology, then you will get a backlog of tasks to be performed.

Architectural Design Phase

Once the requirements are understood, software architects and developers are beginning to design the software. For design, the software the architect may use an architecture framework to compose in an application by utilizing the existing components, promoting reuse and standardization.

In the same manner, developers are started using some design patterns to solve the algorithm problems inconsistently. In the design, the phase makes a model to represent how the software application will work. And for that, this design phase has some key aspects which include:

• Architecture: architectures are responsible for defining the programming language, industry practice, overall design, and use of any existing template of the organization.
• User interface: it defines how a customer interacts with the software and also how is the software will respond to the inputs.
• Platforms: here we are taking the consideration of the developed software that will run on which platform like Apple Android Windows version Linux.
• Programming: Here, we are defining what programming language will be used and also include the method for solving the problems and performing task applications.
• Communication: here, we define how the application can communicate with other assets to search a central server, database, and separate instance of the application.
• Security: hair where try to figure out how to secure the application which may include SSL certificate to the application, password protection, secure storage of files & and Secure storage of credentials.

While taking consideration of all the points, a prototype can be prepared. This prototype is an earlier version of the software which demonstrates how the application will look like in the future and how it will work.

This design and the prototype can be demonstrated in front of the stakeholders to get feedback or improve the application. Because making a prototype is less expensive as compared to rewrite the code to make a change in the development phase.

The output of this phase is design documents that list all the patterns and components selected for the project.

Software Development Phase

In this phase, the developers are started writing the code with the chosen programming language. If that’s a small project, then the complete system is handled by a single developer but if that’s a big project, in that case, that my broken off with several teams.

If there are multiple teams are working under this project to develop the application. In that case, is a source code management application will be introduced which helps the developer to track the code changes.

Depending on the software testing methodology, if you are following is a methodology, then hear the timebox is divided with sprints, or if you are following waterfall methodology, then the complete application will be delivered.

Regardless of methodology, the development teams should produce software as quickly as possible. And also the business stakeholders are engaged regularly in the agile methods to ensure that the expectation are being met.

The output of this phase is testable and functional software.

Testing Phase

The testing phase is one of the crucial stages of the SDLC model. It is impossible to deliver a quality software product without software testing. The testing time has created a test plan based on the predefined software requirement.

The test plan contains the availability of resources for testing, instructions, and assignments for testers. Also, the test plan includes what type of test should be conducted and which test reports should be delivered to the technical executive and decision-makers.

In the testing phase of SDLC, the developed software is going through a variety of testing measure the quality of the product. which includes:

• Code quality
• Unit-testing
• Integration testing
• Performance testing
• Security testing

the best way to do all this type of testing without skip is to automate them. For performing all this type of testing, you can take the help of the famous automation tool like Selenium.

The output of this testing phase is a functional software, which is ready for deployment to the production environment.

Deployment Phase

In the development phase, the application is made available to the end-user. Many companies prepare the deployment phase. but before shipping or deliver the final product to the customer, there are some procedures and preparations of activities are involved, like:

• Documentation
• Transferring ownership and licensing
• Deploying and installing the product on the customer system

the output of this phase, Software release to production of the working software.

Maintenance Phase

At this point, the development cycle is almost finished, because the application is already delivered and being used by the end customers. But still, the maintenance phase is critical because the end-user may have found some bugs which are not during the testing. These errors to be resolved as soon as possible.

Besides bug fixtures, you make get some additional feature requests for future releases. And each new release request is lunch a new development life cycle.

Advantages / Benefits of SDLC:

• The process of SDLC gives software developers and clients a clear and defined goal.
• It provides better understanding on how the project will be accomplished in phases or stages.
• It facilitates planning, control, data management, technical guidance and implementation processes of applications’ development.
• Better quality assurance factor and less rework is guaranteed by the SDLC.
• The final product will be solid and reliable because it underwent intense testing in the process of development.
• It offers an organized approach which is easy to understand and less confusing for both developers and clients alike.
• Major roles are defined clearly during the SDLC as well as their accomplishments are also defined.
• It has a structure which can accommodate a team of people with different skills and expertise having various roles to play in the project’s success.
• SDLC allows for adjustments or changes on strategy, approach or tactics even in the middle of the development process without affecting its successful outcome.
• Software versioning is facilitated by the SDLC as it has a proper version control system.
• Better decision making is possible because of accurate and detailed documentation which can be easily accessed by stakeholders or clients alike.
• Software Development Life Cycle promotes teamwork, synergy and coordination among team members due to its clear definition on responsibilities and accountabilities of each member involved in the process.
• It ensures, less costly and more cost-effective software development because all the costs from each project phase are included in the total budget.
• The SDLC facilitates smooth rollout of applications as it has a proper deployment planning system to follow.
• Application maintenance is also provided for as part of the Software Development Life Cycle.
• Modern SDLC is not limited to programming languages but can be applied in other domains like architecture and design as well.
• Better understanding of a project’s scope, issues and possible solutions are possible due to the clear definition of roles and responsibilities set in the process of SDLC.
• There is less or no ambiguity in responsibilities and accountabilities of each team member.
• The software product’s quality is guaranteed because it is subjected to intense testing at the conclusion of each phase or stage of SDLC.
• Shortened development time is possible with a well-established Software Development Life Cycle as compared to non-structured approach or other software development process methodology.
• There is a high level of predictability due to the involvement and collaboration of all concerned parties in the software development cycle.
• It assures lesser cost overruns compared to project without Software Development Life Cycle or proper SDLCM implementation structure, processes and procedures
• Applications which are developed following an established SDLC process are more reliable and less prone to errors or bugs.
• It can be integrated into other process of software development like Software Engineering, Software Development Processes, Information Technology Service Management, Project Management among others.

Disadvantages / Problems / Limitations:

• Often the SDLC is implemented by project managers who are not technically sound in computer science and this often leads to poor project management due to the very technical nature of software development.
• It is cumbersome and difficult to implement especially for those who are unskilled or unfamiliar with this kind of methodology.
• The SDLC can be applied only in small scale projects which have a defined scope, time frame and budget.
• It cannot be applied in projects that require flexibility, creativity and adaptability which are inherent to many innovative software developments.
• The SDLC is mostly applicable for software development only but can also be used in other disciplines like architecture and design

Other SDLC Models

There are multiple software development models available, and various organizations follow those. Some of these models are:

• Waterfall model
• Spiral model
• Iterative-incremental model
• V-shaped model

Final Words

When we are planning to develop software, then it always starts with a concept, and after that, it slowly goes with some series of phases like analysis to deployment. For the development of any type of software, we are following several methods.

But out of all of these methods, there are two methods that are mostly used by various organizations. Those are Waterfall model which is a very common and another one is a soil which is rapidly overtaking in companies like large and small. Whichever method you choose but use the right tool for the job.

It is very much challenging to deliver software without following any method. Because we can say like there is no perfect method, but it’s far better to use a method than none.