System Design Vs System Architecture

System design and system architecture are closely related concepts but they refer to different aspects of creating and managing a system. 

Here’s a breakdown of the differences between the two:

System Architecture

Definition: System architecture is the conceptual model that defines the structure, behavior, and more views of a system. It provides a high-level view of the system, outlining its major components and their relationships.

Focus Areas:

1. Components and Modules: Identifying the major components or modules of the system.
2. Interactions: Defining how these components interact with each other.
3. Technology Stack: Choosing the appropriate technologies and platforms.
4. Standards and Protocols: Deciding on the standards and protocols to be followed.
5. Scalability and Performance: Ensuring the system can handle growth and performs well under load.
6. Security: Incorporating security measures at a high level.

Output:

• Architectural diagrams (e.g., system context diagram, high-level system diagram)
• Technical stack choices
• Architectural patterns (e.g., microservices, layered architecture)

System Design

Definition: System design is the process of defining the detailed specifications of the system. It focuses on the implementation aspects and includes planning the specific components, data flows, and algorithms that will be used to meet the system's requirements.

1. Focus Areas:
2. Detailed Component Design: Defining the internal structure of each component or module.
3. Data Flow and Storage: Designing how data moves through the system and where it is stored.
4. User Interface: Planning the design and layout of the user interface.
5. APIs and Interfaces: Specifying the APIs and interfaces for interaction between components.
6. Algorithms: Defining the algorithms and logic used within the system.
7. Integration: Planning how the system will integrate with external systems or services.

Output:

• Detailed design documents
• Data flow diagrams
• Database schemas
• API specifications
• UI/UX designs

Key Differences

1. Abstraction Level:
   • System Architecture: High-level, abstract view.
   • System Design: Low-level, detailed view.
2. Focus:
   • System Architecture: Overall structure and relationships between major components.
   • System Design: Specific details of each component and how they are implemented.
3. Stakeholders:
   • System Architecture: Often involves senior technical leaders and architects.
   • System Design: Often involves developers, designers, and engineers who implement the system.

Example

For a web application:

• System Architecture might define the use of a three-tier architecture with a web server, application server, and database server, using RESTful APIs for communication, and choosing technologies like React for the frontend, Node.js for the backend, and PostgreSQL for the database.
• System Design would specify how the user authentication module is implemented, the exact structure of the API endpoints, the schema of the database tables, the design of the login page, and the logic for handling user sessions.

Conclusion

In summary, system architecture provides the high-level blueprint, while system design focuses on the detailed implementation plan.