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All computers use three types of basic buses. The name of the bus is generally determined by the type of signal it is carrying or the method of operation. We group the buses into three areas as you see them in their most common uses. They are as follows:

Control (also called timing and control bus) bus,

Address bus, and

data (also called a memory bus) bus.

Instruction (I), Operand (O), Input/Output Memory (I/O MEM) or Input/Output Controller (IOC), and Computer Interconnection System (CIS) Time multiplexed bus

Control Bus

The control bus is used by the CPU to direct and monitor the actions of the other functional areas of the computer. It is used to transmit a variety of individual signals (read, write, interrupt, acknowledge, and so forth) necessary to control and coordinate the operations of the computer. The individual signals transmitted over the control bus and their functions are covered in the appropriate functional area description.

Address Bus

The address bus consists of all the signals necessary to define any of the possible memory address locations within the computer, or for modular memories any of the possible memory address locations within a module. An address is defined as a label, symbol, or other set of characters used to designate a location or register where information is stored. Before data or instructions can be written into or read from memory by the CPU or I/O sections, an address must be transmitted to memory over the address bus.

Data Bus

The bidirectional data bus, sometimes called the memory bus, handles the transfer of all data and instructions between functional areas of the computer. The bidirectional data bus can only transmit in one direction at a time. The data bus is used to transfer instructions from memory to the CPU for execution. It carries data (operands) to and from the CPU and memory as required by instruction translation. The data bus is also used to transfer data between memory and the I/O section during...