When we look at communication on notebook motherboard , i think it embodies the latest communication technology developed till now. If we discuss communication(chip-to chip , chip to device) on notebook motherboard, it can be very easily understood , if we take analogue of computer network . Like in computer network , we have router, modem , LAN cable and computers are connected on LAN each with its own IP . similarly in notebook there are various chips like CPU , north bridge, south bridge, IO controller, BIOS and all need to communicate each other .And each device /chip have its own address and the process of memory address initialization occurs when bios is read at boot time. Where are the lan wires on the notebook ? its thr in form of buses and then we have differenty types of buses and the core type is same PCI or PCI Express . Lets look connection between north bridge(GMCH/MCH) and CPU , we can see DMI(Direct media interface) written on schmeatics , this is a type of PCI in board implementing below ICH5(older boards) and this connection is type of PCI Express(newer boards implementing ICH8 and more) . Now where is the router on notebook .As we know router routes/forwards the address. , similarly memory controller ( memory controller is in GMCH and newer boards In CPU) , so GMCH is the router , it lets CPU to access any components. The CPU doesnt know how many devices are thr and how much ram is thr , it just forwards the address to GMCH , and the magic is that BIOS address is hardcoded , its address has remain unchanged since the evolution of computer and CPU forwards its request at same address in any kind of boards(i3, dual core, core2 duo) . In my coming post i will give insight in more details .