Software architecture refers to the high-level structure of a software system, the discipline of creating such structures, and the documentation of these structures. It's the blueprint for the software system, providing a solid foundation on which software can be built. It needs to be designed well in order to sustain the system's growth and make sure that future changes can be accommodated without massive rework.

There are several main design architecture principles in software development, including:

1. Separation of concerns design principle: this principle involves dividing the software into distinct, independent, and modular components that can be developed, tested, and maintained separately.

2. Modularity design principle: this principle involves breaking the software down into smaller, self-contained modules or components, each with a specific and well-defined responsibility.

3. Abstraction design principle: this principle involves hiding the details of a component's implementation behind a simplified, generic interface.

4. Encapsulation design principle: this principle involves wrapping data and behavior within a single unit, such as a class, to hide the implementation details from other parts of the system.

5. Loose coupling design principle: this principle involves minimizing the interdependence between components, allowing them to change independently without affecting the rest of the system.

6. High cohesion design principle: this principle involves designing components so that they have a single, well-defined purpose and work together seamlessly.

7. Single Responsibility design principle: this principle states that each component or module should have a single, well-defined responsibility, and should not be concerned with other responsibilities.

8. Dependency Inversion design principle: this principle states that high-level components should not depend on low-level components, but rather both should depend on abstractions.

These principles provide a foundation for building scalable, maintainable, and flexible software systems. However, it's important to note that each principle can have trade-offs, and finding the right balance between these principles is a key aspect of software architecture and design.

Why we should bother ?

Design architecture principles are important for a number of reasons:

1. Improved maintainability: by following design principles, a software system can be structured in a way that makes it easier to understand, modify, and maintain over time.

2. Increased reliability: by following well-established design principles, you can reduce the risk of introducing bugs and other issues into the system.

3. Improved scalability: by following design principles that encourage modularity and separation of concerns, a software system can be more easily scaled to meet the changing needs of your organization.

4. Better collaboration: design principles help to create a common language and shared understanding among team members, making it easier for multiple people to work together on a project.

5. Better documentation: by following design principles, you can create a more organized and structured code base, making it easier to understand and document the system's behavior.

6. Reusability: by following design principles that encourage the reuse of code and components, you can reduce the amount of redundant code in your system, making it easier to maintain and update.

7. Improved performance: by following design principles that encourage efficient use of resources, such as memory and processing power, you can improve the performance of your system and make it more responsive to users.

In summary, using design architecture principles can help you build better, more reliable, and more maintainable software systems. By following these principles, you can create software that is better suited to the needs of your organization and your users, and that can evolve and adapt over time to meet changing requirements.

Implementations and patterns

Here are some examples of how design architecture principles can be implemented in software development:

1. Model-View-Controller (MVC): this is a common design pattern used in web development to separate the presentation layer (the view), the data model (the model), and the controller, which coordinates the interactions between the two.

2. Model-View-Presenter (MVP): this is a variation of MVC that separates the view from the controller even further, by introducing a separate presenter component that handles the logic for updating the view.

3. Service Oriented Architecture (SOA): this is an approach to software development that emphasizes the separation of concerns into independent, modular services that can be combined to create larger, more complex systems.

4. Microservices Architecture: this is a variation of SOA that emphasizes the use of small, independent services that are loosely coupled and can be developed, deployed, and managed independently.

5. Event-Driven Architecture: this is an approach to software development that emphasizes the use of events to trigger changes in the system, rather than direct calls between components.

6. Command and Query Responsibility Segregation (CQRS): this is a design pattern that separates the components responsible for reading data (queries) from those responsible for writing data (commands), in order to improve performance and scalability.

7. Domain-Driven Design (DDD): this is a software design approach that emphasizes the modeling of real-world concepts and business processes in the software system.

These are just a few examples of how design architecture principles can be applied in software development. There are many others, and the best approach will depend on the specific needs and constraints of your project.