Software Design Module PDF

**MODULE 1** **Software Design** - process of defining the architecture, components, interfaces, - a blueprint that guides the implementation ***Importance of software design in the development process*** - create a system that meets both functional and non-functional requirements whi...

**MODULE 1** **Software Design** - process of defining the architecture, components, interfaces, - a blueprint that guides the implementation ***Importance of software design in the development process*** - create a system that meets both functional and non-functional requirements while being scalable, maintainable, and efficient. - It involves translating software requirements into a more detailed design specification, **Objectives of Software Design** ***Ensuring software meets user needs and requirements*** - to ensure that the software meets the needs of its users. - involves understanding user requirements and translating them into a design that fulfills those requirements. - By focusing on user needs, software designers can create solutions that are intuitive, user-friendly, and effective. **Key Objectives of Software Design** 1. **Correctness**: must meet all functional and non-functional requirements. 2. **Modularity**: Dividing the software into smaller, manageable, and independent modules. 3. **Maintainability**: easily updated or extended in the future. 4. **Efficiency**: Optimize resource use, including time, memory, and other system resources. 5. **Flexibility**: able to adapt to changing requirements. 6. **Reusability**: Code and components should be reusable **Software Design Principles** **Overview of [software design principles]** - are guidelines to ensure that the system architecture is clean - help in facilitating changes without breaking existing functionality. ***Single Responsibility Principle (SRP)*** - each module should have only one reason to change ***Key Principles of Software Design*** - **Open/Closed Principle:** open for extension but closed for modification. - **Liskov Substitution Principle:** Subtypes should be replaceable by their base types without altering the correctness of the program. - **Interface Segregation Principle:** Clients should not be forced to depend on interfaces they do not use. - **Dependency Inversion Principle:** High-level modules should not depend on low-level modules; both should depend on abstractions. **Key strategies:** **Top-Down Approach** - most general system refining into detailed components. - allows for a high-level understanding of the system and facilitates early identification of potential issues. **Bottom-Up Approach** - detailed components into higher-level systems. - allows for early validation of individual components and promotes code reusability. **Iterative Design** - allowing for refinement with each cycle. - requirements may change or evolve, as it allows for flexibility and adaptability. **Prototyping** - preliminary version of the system to validate design choices before full-scale implementation. - helps in refining requirements, identifying potential issues, and avoiding major design flaws **Software Design Models** - **Architectural Model** - represents the overall structure of the software, - It provides a high-level understanding of the system\'s organization and helps in identifying key components and their interactions. - **Component-Level Design Model** - how individual software components function and interact. - It provides a detailed view of the system\'s components, their responsibilities, and their interfaces. - **Data Flow Models** - represent the flow of data through the system and how inputs are transformed into outputs. - help in understanding the system\'s behavior and identifying potential bottlenecks or inefficiencies. - **State Transition Models** - how the system behaves in response to external events. - used to identify potential issues or error states. - **Object-Oriented Models** - use objects and classes to represent system components and their relationships. **MODULE 2** **Functional and Non-Functional Requirements** **Functional Requirements**\ **-** specify what the system must do, like an ATM processing withdrawal. 1. **User Authentication:** Login, logout, password recovery, and user management. 2. **Data Processing:** CRUD (Create, Read, Update, Delete) operations on data. 3. **Payment Processing:** Handling transactions, invoices, and refunds. 4. **Notifications:** Real-time updates, email alerts, and push notifications. 5. **Reporting:** Generate and export reports 6. **User Permissions:** Role-based access control 7. **Search Functionality:** Full-text search 8. **Integration with Other Systems:** APIs for third-party 9. **Data Backup:** Scheduled backups and restore options **Non-Functional Requirements**\ **-** describe how well it performs, such as completing transactions in under 5 seconds. 1. **Performance:** Fast load times, processing speed 2. **Scalability:** handle increasing user loads. 3. **Security:** Encryption, secure data storage, access control. 4. **Usability:** Intuitive UI/UX, accessible for all users. 5. **Reliability:** System uptime, fault tolerance, error handling. 6. **Maintainability:** Easy to update, modify, debug. 7. **Portability:** Compatibility with various devices and operating systems. 8. **Compliance:** Adherence to industry standards (e.g., GDPR, HIPAA). 9. **Localization:** Support for multiple languages **Documentation:** Detailed user and technical documentation ***The Software Requirements Document (SRD)*** - serving as a contract between stakeholders and developers. - ensures clear communication, reduces misunderstandings, **Requirements Specification** - precisely defines system requirements, typically in the SRD. Clear, unambiguous, verifiable, & complete specifications to ensure it's understandable & testable. **Requirements Engineering Processes** - involves defining, documenting, and managing software requirements through elicitation, specification, validation, and management. - It\'s essential for aligning technical capabilities **Requirements Elicitation and Analysis Process** - **elicitation** process gathers requirements through interviews, focus groups, and observations. - **Analysis** then prioritizes and refines these requirements to resolve conflicts and remove redundancies. **Requirements Management** - minimizes the impact of changes, reduces errors, and ensures traceability back to stakeholder needs. - Tools like **JIRA** or **IBM** Rational **DOORS** facilitate requirements management by providing automated tracking and version control.