PCI Bus in Computer Architecture
A device communications with a computer system by sending signals over a cable or even through the air. The device communicates with the machine via a connection point that says a Port. If one or more devices use a common set of wires, the connection says a Bus. When Device A has a cable that plugs into Device B, and Device B has a cable that plugs into Device C and Device C plugs into a port on the computer. This arrangement says a PCI Bus or Daisy chain.
PCI Bus Architecture:
It stands for Peripheral Component Interconnect. PCI Bus Architecture is based on ISA (Industry Standard Architecture) Bus. PCI is a local computer bus for attaching hardware devices to a computer. The PCI bus connects the processor memory subsystem to the fast devices and an expansion bus that connects relatively slow devices such as a keyboard and serial and parallel ports. In the upper right position of the figure: Three devices are connected on a SCSI bus that is plugged into a SCSI (Small Computer System Interface) controller.
A controller is a collection of electronics that can operate a port, a bus, or a device. A serial port controller is an example of a single device controller. It is a single chip in a computer that controls the signals on the wires of a serial port. The controller has one or more registers for data and control signals. The processor communicates with the controller by reading and writing bit patterns in those registers.