Software Design Module 1

Software Design Module 1

• Software design is a blueprint for software implementation, guiding the creation of components, interfaces, and architecture.
• Good software design ensures the system meets functional and non-functional requirements, is scalable, maintainable, and efficient.
• It translates software requirements into detailed design specifications.
• Key objectives of software design include correctness (meeting requirements), modularity (dividing into smaller parts), maintainability (ease of future updates), efficiency (optimal resource use), flexibility (adaptability to change), and reusability (reusable components).

Key Strategies

• Top-down approach: Starts with a general system overview, then refines into components. This allows for high-level understanding and early issue identification.
• Bottom-up approach: Begins with detailed components and builds higher-level systems. Early validation of component functionality and reusability is possible.
• Iterative design: Design is refined with each iteration. It is adaptable to changing requirements, useful for evolution.
• Prototyping: A preliminary version to confirm design choices and avoid major flaws, refining requirements.

Software Design Models

• Architectural Model: Represents the overall system structure, showing system components and interactions. Crucial for high-level understanding of the system.
• Component-Level Design Model: Describes individual component functions, responsibilities, and communications. Provides a detailed view of components.
• Data Flow Models: Illustrates data movement through the system and transformation to outputs. Helps understand system behavior and potential bottlenecks.
• State Transition Models: Shows how the system reacts to external events. Used to identify potential issues and error states.
• Object-Oriented Models: Use objects and classes to represent system components and their relationships.

Software Design Principles

• Single Responsibility Principle (SRP): Each module should have only one reason to change.
• Open/Closed Principle: Extensible designs are open to additions, but closed to modifications.
• Liskov Substitution Principle: Subtypes should replace their base types without altering correctness.
• Interface Segregation Principle: Clients shouldn't depend on interfaces they don't use.
• Dependency Inversion Principle: High-level modules shouldn't depend on low-level modules; both should depend on abstractions.

Module 2: Functional and Non-Functional Requirements

• Functional Requirements: Define what the system must do. Examples include: User authentication, data processing, payment processing, notifications, reporting.
• Non-Functional Requirements: Describe system performance and behavior. E.g., performance (speed, scalability), security, usability, reliability, maintainability, portability, compliance.
• Software Requirements Document (SRD): A contract that clarifies system requirements, facilitating communication and reducing misunderstandings.
• Requirements Specification: Precise, clear, verifiable, and comprehensive documentation of system requirements.
• Requirements Engineering Processes: Includes elicitation, specification, validation, and management of software requirements (e.g. through interviews, focus groups, and observations)
• Requirements Management: Aims to manage changes effectively, ensuring traceability to stakeholder needs and minimizing errors. Techniques including JIRA or IBM Rational DOORS.

Explore the fundamentals of software design in this quiz. Learn about the key objectives, approaches, and principles that guide effective software implementation. This module covers essential strategies such as top-down and bottom-up design to help ensure your software meets both functional and non-functional requirements.