unit-1 PART -1

[Virtual Presenter] Software is a program or set of programs containing instructions that provide the desired functionality. Engineering is the process of designing and building something that serves a particular purpose and finds a cost-effective solution to problems. Software Engineering is the process of designing, developing, testing, and maintaining software. It is a systematic and disciplined approach to software development that aims to create high-quality, reliable, and maintainable software. By following the principles of software engineering and using the appropriate tools and methodologies, software developers can create high-quality, reliable, and maintainable software that meets the needs of its users..

[Audio] The rapid increase in software demand, the complexity of software, and software challenges led to the difficulty of writing useful and efficient computer programs in the required time, resulting in a software crisis. As the workforce, methods, and tools remained unchanged despite these increases, software budget problems, efficiency problems, quality problems, management problems, and delivery problems emerged, ultimately leading to a software crisis..

[Audio] The cost of owning and maintaining software was as expensive as developing the software. Projects were running overtime. Software was very inefficient, with poor quality and often failing to meet user requirements. On average, software projects took twice as long to complete as scheduled. Software was rarely delivered on time, and non-optimal resource utilization made it difficult to modify, test, and improve the software. The complexity of the software itself was also hard to change. These difficulties contributed to the software crisis, which was caused by poor project management, inadequate training in software engineering, inexperienced team members, and limited productivity gains..

[Audio] The Software Development Life Cycle (SDLC) is a process that is followed for software building within a software organization. It consists of a precise plan that describes how to develop, maintain, replace, and enhance specific software. The life cycle defines a method for improving the quality of software and the overall development process..

[Audio] During this stage, we analyze the requirements of our software project by gathering information from various sources such as customer inputs and market surveys. This data allows us to build the foundation of our project, ensuring that it meets the needs of our users. With all the necessary details in hand, we can now design our project and lay the groundwork for success..

[Audio] All requirements for the target software are specified in this stage. These requirements receive approval from customers, market analysts, and stakeholders. This process is facilitated through the utilization of SRS, which outlines all aspects that need to be defined and created throughout the project lifecycle. As a reference, SRS enables software designers to develop the optimal architecture for the software. With the requirements outlined in SRS, various designs for the product architecture appear in the Design Document Specification. Market analysts and stakeholders assess this DDS, considering all relevant factors, and select the most practical and logical design for development..

[Audio] Developers start the fundamental development of the product at this stage. They use a specific programming code based on the design in the DDS. It is essential for coders to adhere to the protocols established by the association. Conventional programming tools, including compilers, interpreters, and debuggers, are employed, alongside popular programming languages such as C/C++, Python, and Java, in accordance with software regulations..

[Audio] After the development of the product, thorough testing is necessary to guarantee its seamless execution. All potential flaws are identified, corrected, and retested to ensure that the product meets the quality requirements outlined in the Software Requirements Specification. Documentation, training, and support are also critical components of this stage. Well-crafted documentation serves as a valuable resource, providing insight into software processes, functions, and maintenance procedures. Additionally, documentation offers guidance on how to utilize the product effectively. Training plays a vital role in enhancing employee performance by fostering skill development and attitude adjustments. This enables employees to work more efficiently and effectively..

[Audio] After the software is developed, it is time to deploy it. This stage is critical because it marks the transition from the development team to the users. The deployment process involves installing the software on the target environment, configuring it according to the user's needs, and ensuring that it works seamlessly. This stage requires careful planning and coordination between the development team, the operations team, and the users..

[Audio] The Waterfall Model was introduced by Winston Royce in 1970. This model consists of five phases: Requirements analysis and specification, design, implementation, and unit testing, integration and system testing, and operation and maintenance. Each phase follows the previous one, and none of them overlap. The developer must complete each phase before starting the next one. This model gets its name from its diagrammatic representation, which resembles a waterfall. The first phase is Requirements analysis and specification, where we aim to understand the exact requirements of the customer and document them properly. Both the customer and the software developer work together to document all the functions, performance, and interfacing requirements of the software. This phase creates a large document called the Software Requirement Specification, which contains a detailed description of what the system will do in common language..

[Audio] During the implementation phase, the design is put into action. If the Software Design Document (SDD) is comprehensive, the coding process unfolds seamlessly, since all the necessary details are readily available to software developers. As the code undergoes testing, it is meticulously scrutinized and refined. Initially, small modules are tested independently. Subsequently, these modules are evaluated by incorporating additional code to verify their interactions and the flow of intermediate outputs..

[Audio] The Waterfall model's progression is intuitive, allowing teams to complete an entire step before moving onto the next one. This approach brings roadblocks to light immediately, reducing the likelihood of half-finished projects. Additionally, the methodology doesn't require special training or certifications, making it easier for team members to adapt. By outlining the process visually and explaining the methodology, teams can jump into the Waterfall system without a steep learning curve. The model determines the end goal early, eliminating the risk of getting bogged down during the project. Furthermore, Waterfall emphasizes a clean transfer of information at each step, ensuring accessible information for new team members. This characteristic maximizes benefits by staying organized with the right process..

[Audio] The Waterfall model makes changes difficult because it's based on following a set of steps that keep teams always moving forward. Once a team has committed to a plan, making changes becomes challenging. The methodology doesn't leave room for unexpected changes or revisions, which can lead to wasted time and energy if a project needs to pivot..

[Audio] The Waterfall methodology offers a clear project structure, enabling teams to concentrate on a single objective and monitor progress effortlessly. With meticulous planning, teams can establish costs and deadlines beforehand, guaranteeing everyone is aligned. The procedure is repeatable, making it simpler to utilize successful strategies for future projects. Thorough project documentation and enhanced risk management are also significant advantages. Furthermore, the Waterfall approach fosters increased responsibility and accountability among team members, as well as reduced delays caused by additional requirements..

[Audio] Agility is achieved by tailoring the process to fit the unique needs of a specific project, eliminating non-essential activities that waste time and effort. The Agile Model encompasses various development processes that share fundamental characteristics yet exhibit subtle variations. The steps involved in agile software development life cycle models include requirement gathering, design the requirements, construction/iteration, testing/quality assurance, deployment, and feedback. During requirement gathering, the development team interacts with customers to plan the necessary resources and timeframe for building the project. Designing the requirements involves creating wireframes and user interface designs. Construction/iteration commences actual project development, aiming to deliver a functional product. Testing/quality assurance entails unit testing, integration testing, and system testing. Deployment involves releasing the working project to end-users, while feedback solicits customer input, addresses issues, and refines the product based on customer feedback..

[Audio] Agility is key to adapting to technical and environmental changes. Incremental development ensures that each increment contains functional code that can be tested and verified by the customer. Customer feedback drives the creation of the next increment, and software increments are delivered within a short timeframe. Each increment is evaluated regularly, allowing adjustments to be made as needed. The Agile model is used when frequent modifications are necessary, when a highly qualified team is available, when customers are readily accessible, and when projects require flexible schedules and budgets. The advantages of Agile include reduced development time, improved collaboration, and customer satisfaction. However, there are disadvantages, such as the potential for confusion due to informal documentation, difficulty in handling complex dependencies, and the need for high-level expertise from team members..

[Audio] Due to the absence of proper documentation, when the project completes and the developers are assigned to another project, maintenance of the developed project can become a problem. The Prototyping Model is one of the most popularly used Software Development Life Cycle Models. This model is used when the customers do not know the exact project requirements beforehand. A prototype of the end product is first developed, tested, and refined as per customer feedback repeatedly till a final acceptable prototype is achieved which forms the basis for developing the final product. The system is partially implemented before or during the analysis phase, thereby allowing the customers to see the product early in the life cycle. The process starts by interviewing the customers and developing the incomplete high-level paper model. This document is used to build the initial prototype supporting only the basic functionality as desired by the customer. Once the customer figures out the problems, the prototype is further refined to eliminate them. The process continues until the user approves the prototype and finds the working model to be satisfactory..

[Audio] We have finally reached the last step of our prototyping model, where we implement the product and maintain it. This marks the culmination of all our efforts, as we test the final system, distribute it to production, and ensure it runs smoothly to prevent any potential failures. We have successfully completed our prototyping model..