In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers). A bus can be thought of as a communication pathway that allows data to travel between different components. There are different types of buses in a computer, including internal buses, external buses, and system buses).

• Internal Bus: Also known as internal data bus, memory bus, system bus, or front-side bus, it connects all the internal components of a computer, such as CPU and memory, to the motherboard. Internal data buses are also referred to as local buses because they are intended to connect to local devices. This bus is typically rather quick and is independent of the rest of the computer operations).

• External Bus: This type of bus is used to connect various internal peripherals such as a printer or hard drive to the system board.

• System Bus: System buses are used to transfer data between the CPU and main memory. They also control the exchange of data between other components such as video cards or sound cards. The system bus connecting the CPU and memory is one of the defining characteristics of the system, and often referred to simply as the system bus. It is possible to allow peripherals to communicate with memory in the same fashion, attaching adapters, either on the motherboard or in the form of expansion cards, directly to the system bus. This is commonly accomplished through some sort of standardized electrical connector, several of these forming the expansion bus or local bus).

Buses may use multiple protocols for exchanging data among devices, including interruptions, polling methods, direct memory access (DMA), clock signals, and serial links. The importance of buses on computers is that they allow different components to be connected together, which allows for the efficient transfer of data between components.