Topic summary
Address bus
Extracted from the Wikipedia article Bus (computing).
Address bus
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 transfer simultaneously. For example, a system with a 32-bit address bus can address 2 (4,294,967,296) memory locations. If each memory location holds one byte, the addressable memory space is about 4 GB.