An address bus is a bus that is used to specify a physical address. When a processor or DMA -enabled device needs to read or write to a memory location, it specifies that memory location on the address bus (the value to be read or written is sent on the data bus). The width of the address bus determines the amount of memory a system can address.

An address bus is a computer bus architecture. It is used to transfer data between devices. The devices are identified by the hardware address of the physical memory (the physical address). The address is stored in the form of binary numbers to enable the data bus to access memory storage.