Types Of Buses Posted by shariq shukur , Friday, June 12, 2009 at 5:41 PM, in

Types Of Buses

There are four types of Buses which are used to communicate inside the PC. They are

1. Local Bus


2. System Bus


3. I/O Bus


4. Mezzanine Bus

The local bus exists at the immediate input/output pins in CPU. The System Bus is on the motherboard and it connects RAM to the Processor. The I/O Buses connects I/O subsystems – The Processor. The I/O buses are generally derived from the system bus. The Mezzanine Bus is an intermediate bus between a local bus and I/O bus. It acts as abridge between the I/O buses arc the system bus. The PCI and multibus are examples of Mezzanine Bus.

In the original PC, the system bus and I/O bus were the same. The floating point coprocessor is connected to the local bus of 8088. All other subsystems are linked to the microprocessor through buffers. The motherboards subsystems (RAM, ROM, I/O CHIPS) are connected to X bus (XA, XD, XC). Daughterboard are connected via I/O slots which carry A, D & C Buses. Thus X bus and D Bus Serve both as system bus without any differentiation. In this approach, CPU communicates with both memory and I/O subsystems with the same speed. This holds good for 4-Motherboards also.