Mother Board: The main board of the computer, this holds all the processors, memory and the expansion slots. It’s made up of a chipset (known as the ‘glue logic’), some code in ROM and the various interconnections or buses.
Mother Boards through the Ages: The mother boards in the original computers were very simple. They only had ports for components such as the keyboard and a cassette deck (which acts as the storage for the computer). Other components (like floppy or hard disk controllers) were added in through expansion slots.
Over time. More devices were integrated into the motherboard. This is a slow process. Even though more components were put into the motherboard, other components remain separate, like graphics cards, networking, and sound cards. Some developers tried to create motherboards with EVERYTHING in it. There was plenty of drawbacks though. In a motherboard, it is quite hard to upgrade the specification because the integrated components cannot be moved. The parts that upgrade fastest like graphics, RAM and ROM, tend to be placed in sockets so they can be placed and removed easily.