Motherboard Components(Bus)

Why Bus:-
           A personal computer may transfer data from disk to CPU, from CPU to memory, or from memory to the display adapter. A PC cannot afford to have separate circuits between every pair of devices. A mechanical switch, like the old phone systems used, would be too slow. So we can use bus.

Bus:-
         

              The Bus is simply a common set of wires that connect all the computer devices and chips together. (or) A bus is a common pathway across which data can travel within the computer. This pathway is used for communication and can be established between two or more computer elements. A PC has many kinds of buses, including the following:

•  Processor bus
•  Address bus
•  I/O bus
•  Memory bus

Processor Bus:-
         The processor bus is a communication pathway between the CPU and immediate support chips. These support chips are usually called the chipset in modern systems. This bus is used to transfer data between the CPU and the main system bus.

Address Bus:-
        The address bus actually is a subset of the processor and memory buses. It is used to indicate what address in memory or what address on the system bus are to be used in a data transfer operation.
The size of the memory bus also controls the amount of memory that the CPU can address directly.

Memory Bus:-
        The memory bus is used to transfer information between the CPU and main memory(RAM)  in your system. This bus is either a part of the processor bus itself, or in most cases it is implemented separately by a dedicated chipset that is responsible for transferring information between the processor bus and the memory bus.

I/O Bus:-
       All the motherboards have one or more system I/O buses that are used to expand the computer's capabilities. These buses work closely with expansion cards. The slots in the back of the machine are where expansion cards are placed. These slots allow you to expand the capabilities of your machine in many different ways, and the proliferation of both general purpose and very specific expansion cards is part of the success story of the PC platform.

         Most modern PCs have two different types of bus slots. The first is the standard ISA (Industry Standard Architecture) slot; most PCs have 3 or 4 of these. These slots have two connected sections and start about a half-inch from the back of the motherboard, extending to around its middle. This is the oldest  bus type and is used for cards that don't require a lot of speed: for example, sound cards and modems. Older systems may have ISA slots with only a single connector piece on each; these are 8-bit ISA slots and will only support 8-bit ISA cards.