Computer architecture refers to the set of principles and methods that specify the functioning, organization, and implementation of computer systems. It encompasses the structure, behavior, and design of computers, including the hardware components and the software systems that control and coordinate their operation.

Key Points:
- Set of principles and methods: Computer architecture defines the fundamental principles and techniques for designing and implementing computer systems. It provides a framework for understanding how different components of a computer system interact and work together.
- Functioning: Computer architecture determines how the various components of a computer system, such as the CPU, memory, and input/output devices, function and interact with each other. It specifies the operations and functionalities that can be performed by the system.
- Organization: Computer architecture involves the organization and arrangement of the components within a computer system. It defines the structure and hierarchy of the various hardware components and their connections, as well as the organization of data and instructions in memory.
- Implementation: Computer architecture also deals with the implementation of computer systems, including the design and construction of the hardware components and the development of the software systems that run on them. It encompasses both the physical aspects of computer systems, such as the circuits and chips, as well as the software layers that enable their operation.

Importance of Computer Architecture:
- Performance: Computer architecture plays a crucial role in determining the performance of a computer system. By optimizing the design and organization of the components, it can enhance the speed and efficiency of computations and data processing.
- Scalability: Computer architecture also enables the scalability of computer systems, allowing them to handle larger workloads and accommodate future technological advancements. It provides a foundation for building systems that can be easily upgraded and expanded.
- Compatibility: Computer architecture ensures compatibility between different hardware and software components, allowing them to work together seamlessly. It defines standard interfaces and protocols that enable interoperability and easy integration of various system components.
- Reliability: A well-designed computer architecture enhances the reliability and fault tolerance of a system. By incorporating redundancy and error detection mechanisms, it can prevent and recover from hardware and software failures.
- Power Efficiency: Computer architecture also considers power efficiency and energy consumption. It aims to minimize power usage while maintaining optimal performance, especially in mobile and embedded systems.

In conclusion, computer architecture is a set of principles and methods that define the functioning, organization, and implementation of computer systems. It provides the foundation for designing and building efficient, scalable, and reliable computer systems.