In a computer, the term bus refers that paths between the components,· actually a bus, is a gro·up of a wire. The bus is the com·mon pathway through which the processor’s end /receive data and commands to/from primary and secondary storage and all can transport 8 bits at a time whereas a bus with 16 lines can transport 16 bits at a time.
Types of Computer Bus:
There are two main buses in a computer:
1. Data Bus
2. Address Bus
The data bus is an electrical path that connects the central processing unit (CPU) memory, and the other hardware devices on the motherboard. Actually, the bus is a group of parallel wires. The number of wires in the bus effects, the speed at which data can travel between components, just as the number of lanes on highway effects how long it takes people to get to their destinations.
Because each wire can transfer one bit at a time, an eight-wire bus can move eight bits at a time. A 16-bit bus can transfer two bytes and a 32-bit bus can transfer four bytes at a time.
The second bus that is found in every microcomputer is the address bus. The address bus is a set of wires similar to the data bus but it connects only the CPU and memory and all it carries are memory addresses. The reason that the address bus is important is that the number of lines in it determines the maximum number of the memory address.
For example, one byte of data is enough to represent 2 = 256 different values, if the address bus could carry only eight bits at a time, the CPU could address only 256 bytes of memory. Most of the early PCs had 20-bit address bus, so the CPU could address only 2(20) bytes or.1 MB of data.