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We have mentioned that a microcomputer includes three fundamental components, Central Processing Unit (CPU), Main Memory (MM), and Input/Output (I/O). These three components are connected by sets of parallel electric conductors (wires), called buses. A bus is a set of parallel connections between components. There are three types of buses in a microcomputer: address, data, and control. The address bus is used mainly by the microprocessor to indicate which particular address in main memory or which I/O port needs to be accessed. The data bus is used for retrieving information from main memory or I/O for the microprocessor, or for storing the information from the microprocessor to memory or I/O. The control bus is responsible for transmitting task commands such as “read” and “write” to the memory and I/O components and for receiving corresponding responses from them.