Ans : BUSES :
A bus is a collection of wires that acts as a communication path between CPU and other devices through signal transfer. The bus width determines the speed of data transmission. There are also local buses that connect elements within the CPU and buses which connect the computer to external memory and peripherals.
WORKING OF BUSES :
A processor communicates with I/O devices and memory by using signals that travel along a set of wires or connections called bus.
TYPES OF BUSES :
There are three different forms of buses on the basis of signal type they carry.
They carry address , control and data signals , so the three main types of buses are
o Address Bus
o Control Bus
o Data Bus
Address Bus : It is the connection between the CPU and main memory which transmit the address from which the CPU will read or write.
(1) It is used to identify particular locations in main memory where data is stored. (2) The number of bits in the address bus can determine the amount of memory the CPU can address. In modern PCs there are 36 address lines to access the 64 GB of main memory theoretically. In actual it is less & depends on quality of chipset and motherboard.
Control Bus :
It is a physical connection between CPU and other devices which carries the control information.
(1) It carries signals that report the status of various devices. (2) For example one line of the bus is used to indicate whether the CPU is currently reading from or writing to main memory.
Data Bus :
It is communication route through which data can travel between the computer’s CPU, memory and peripherals.
(1) It transfers data signals between computer’s CPU , memory and peripheral devices. (2) Each wire transmits a single bit at a time so 8-bits bus can transfer 8-bits at a time and so on.