SDLC (Software development life Cycle)

This ppt contains all information about SDLC along with its phases and Models

1. SDLC (Software Development Lifecycle) By: Prithviraj Date: 31-03-2023

2. What is SDLC ? SDLC stands for Software Development Lifecycle It is a set of planned activities for developing any software product Using SDLC is very important for developing a software, SDLC divides all the tasks to be followed while developing a software into various phases which makes the software most accurate and perfect satisfying all the requirements and also for maintenance of the software Without SDLC, it becomes tough for software project managers to monitor the progress of the project.

3. Phases of SDLC There are 6 stages of SDLC which are: Planning and Requirements Analysis Designing Development/Coding Testing Deployment and Maintenance

4. Planning and Requirements It is the first and the most important phase of SDLC In this phase the Business analyst collects the client’s requirements Based on that information it is then used to plan the basic project approach , expenditure, risk analysis, technical analysis, etc. After planning a document is prepared called BRS (Business requirement specification)

5. Analysis Once the requirement analysis is completed the next step is to make SRS (Software requirement specification) based on BSR (Business requirement specification) SRS document consists of all the product requirements to be designed and developed during the project Based on SRS, two documents are further made that are FRS (Functional requirement specification) and SRS (System requirement specification)

6. Designing Based on the requirements specified in SRS, product architecture is proposed and a document is made called DDS (Design Document Specification) System architect will convert the design into LLD (Low-Level Design) and HLD (High-Level Design) which can de done by third-party application if required LLD - HLD -

7. Development The coding of the project is started as per DDS during this stage. DDS helps in coding for accomplishing the project without much hassle. Developers must follow the coding guidelines defined by their organization or manager and programming tools like compilers, interpreters, debuggers, etc. are used to generate the code. Different high-level programming languages are used such as C, C++, Pascal, Java, and PHP are used for coding. The programming language is chosen with respect to the type of software being developed.

8. Testing This stage refers to the testing of the software where software’s defects are reported, tracked, fixed, and retested until the product reaches the quality standards defined in the SRS (Software Requirement Specification) Testing can be done manually and or by using automation tools

9. Deployment and Maintenance Deployment Once the product is tested and ready to be deployed, it is released in the market. Maintenance Once the product is deployed in the market the client may want to update or want to do some changes to the product then the maintenance part does this task Also, when product users use the software they may give feedback which should be resolved from time to time

10. SDLC Models There are various software development life cycle models which are followed during the software development process. Each model follows a Series of steps to ensure success in the process of software development. There are 9 models of SDLC which are: Waterfall Model V–Model Iterative Model Spiral Model Agile Model Fish Model Big-Bang Model RAD Model (Rapid Application Development) Prototype Model

11. 1. Waterfall Model In the waterfall model all the processes of software development are divided into various phases/parts These parts are nothing but SDLC phases ( Planning and Requirement, Analysis, Designing, Development/Coding, Testing, Deployment and Maintenance) In the waterfall Model the output of one phase is the input to its next phase sequentially When one phase is completed fully (100%) only then next phase will be executed In this model we can’t go back from any phase

12. Waterfall Model Diagram and its Phases

13. Advantages and Disadvantages Of Waterfall Model Advantages Simple and easy to understand and use Easy to manage due to its rigidness Phases are processed and completed one at a time In the Waterfall Model, processes and results are well documented Disadvantages If any changes are required at any phase, the whole process needs to be start from the beginning. For example, if the application has now shifted to the coding phase, and there is a change in requirement, It becomes tough to go back and change it. This Model is not suitable for complex/large projects.

14. 2. V–Model ‘V’ in ‘V-Model’ stands for verification and validation, hence it is called V- Model It is called V-Model because of its structure. On the left side, there are all the verification processes and on the right side, there are all the validation phases, they are connected by the development/coding phase at the bottom, which makes a v shape like structure In this model, testing is associated with every phase, which means that every single phase in the development cycle, they are directly associated to the testing phase Verification – In verification, reviewing is done without executing code. It is the process of evaluation of the product development process to find whether specified requirements meet. Verification involves – Requirement analysis, System design, Architecture design, and Module design

15. Validation - It involves testing of functional and non-functional testing, which is done after executing code. Validation involves – Unit Testing, Integration testing, System testing, and Acceptance testing

16. Advantages and Disadvantages Of V-Model Advantages Simple and easy to understand and use. It works perfectly for smaller projects where requirements are very well understood. Each and every component is tested parallelly at every phase, so the chances of errors are less Disadvantages This Model is not suitable for large and complex Once an application is in the testing stage, it is difficult to go back and change functionality, which means we can’t go back from any phase which affects customer satisfaction

17. 3. Iterative Model This Model is just like Waterfall Model, unlike waterfall Model, in this, we can go back to the previous phase if any changes are required The Iterative Model allows going not only to the previous phase but also allows accessing all of its earlier phases Due to its allowance to go back to the previous or earlier phase, it results in time-saving, cost-saving as well as effort-saving as we have to not start from the beginning again if any change is required It is also called Advanced version of the Waterfall Model

18. Iterative Model Diagram

19. Advantages and Disadvantages Of Iterative Model Advantages This model is easy to understand and execute Some working functionality can be developed quickly and early in the life cycle. Less costly to change the scope/requirements. Testing and debugging during smaller iterations are easy. Disadvantages Requirement changes can cause over budget. Project completion date is not confirmed because of changing requirements.

20. 4. Spiral Model In the Spiral Model all phases are divided into 4 quadrants that are: Objective determination and identifying alternative solutions Identifying and resolving risks Developing and verifying Reviewing and planning for the next phase Objective determination and identifying alternative solutions: This phase starts with gathering the business requirements This phase also includes understanding the system requirements by continuous communication between the customer and the system analyst.

21. Identifying and resolving risks: It is the next phase in the spiral model, in this phase, we calculate and identify all the risks and prepare solutions for that risks before developing the project Developing and verifying : In this phase, the design of the project is made and after designing the developers develop the project after developing the project, the testing team will test the software deeply and then the project goes into the last quadrant/phase Reviewing and planning for the next phase: In this phase, the developed project is shown to the client or manager if any refinement is required it again starts from 1 st quadrant which makes one spiral  

22. A software project repeatedly passes through these phases in iterations called Spirals.

23. 5. Agile Model In this model the ’Agile’ means – fast, so as the name suggests, this model is used when the project deadline is short/less In Agile Model, the tasks are divided into smaller parts which are done from time to time which is called iteration for delivering the project instantly In this Model, a working software build is delivered after each iteration. The final build/iterations hold all the features required by the customer. Customer’s interaction is the backbone of the Agile Model

24. Advantages and Disadvantages Of Agile Model Advantages Resource requirements are minimum. Project delivery time is fast One-to-one communication with the client Changes can be done frequently Little or no planning is required Easy to manage Adaptive software development methods

25. Disadvantages Less documentation may result in confusion and conflicts Transfer of technology to new team members may be quite challenging due to lack of documentation. Depends heavily on customer interaction, so if customer is not clear, team can be driven in the wrong direction

26. 6. Fish Model In the Fish Model, verification and validation are done parallelly at each phase by two different teams.   In Verification, reviewing is done of the whole phase, and In Validation, testing is done of the whole phase. Except deployment and maintenance phases all other processes are done by separate teams and then reports are generated, by the end of the phases.   All the phases when connected via a diagram it makes a fish like structure, that’s why it is called Fish Model

27. Fish Model

28. Advantages and Disadvantages Of Iterative Model Advantages Fish Model is easy to implement   Fish model is used for developing secure and Highly quality software Fish Model is easy to implement and all the documents are created one by one as the phases are completed Disadvantages This SDLC is expensive in terms of cost & time since it involves verification as well as validation on almost all the phases it is not suitable for small projects

29. 7. Big- Bang Model In the Big Bang model of the SDLC model, the model does not follow any specific process The development just starts with the required money and efforts as the input, and the output is the software developed which may or may not be as per customer requirement There is no/less planning Usually this model is followed for small projects where the development teams are very small For example – Academic projects

30. Advantages and Disadvantages Of Big-Bang Model Advantages This is a very simple model to understand Little or no planning required Easy to manage Very few resources required Disadvantages Very High risk and uncertainty Not a good model for complex and object-oriented projects Poor model for long and ongoing projects

31. 9. RAD Model (Rapid Application Development Model) Rapid application development is an SDLC Model that uses minimal planning or not specific planning In this model the project is broken down into small modules and each module may/may not be assigned independently to separate teams. These modules can finally be combined to form the final product using some powerful developer tools such as JAVA, C++, Visual BASIC, XML, etc. is also an integral part of the projects.

32. Advantages and Disadvantages Of RAD Model Advantages It takes less time as powerful RAD tools are used Feedback from the customer is available at the initial stages Expenses are lesser as fewer developers are required and automation tools are used Disadvantages Highly skilled professionals are required for use of powerful tools It is suitable for large projects only

33. 9. Prototype Model In this type of model, a toy model (aka Prototype Model) is made first which is only a dummy model of a project that is made on the basis of the client’s requirement If the client accepts that toy model (Acceptance) then it goes to the next phases which are designing, developing, testing, deploying & Maintenance which is called iterative development If any changes are required by the user, it can be done at an earlier stage itself

34. Advantages and Disadvantages Of Prototype Model Advantages Customer satisfaction Reduce Maintenance cost Reduces time and cost as the defects can be detected much earlier Disadvantages Can take a long time It would be difficult if the customer is not clear with their idea