A bus is the fundamental mechanism used to interconnect memory, I/O devices,
and processors within a computer system. Most buses operate in parallel, meaning that
the bus consists of parallel wires that permit multiple bits to be transferred simultaneously.
Each bus defines a protocol that attached devices use to access the bus. Most bus
protocols follow the fetch-store paradigm; an I/O device connected to a bus is designed
to receive fetch or store operations and interpret them as control operations on the device.