The motherboard is like a car chassis. In a car, everything is connected to the chassis either directly or indirectly. In a PC everything is connectedto the motherboard, either directly or indirectly. A motherboard is a thin, flat piece of circuit board, usually of green or gold color, usually not much larger than an 8.5″ x 11″ piece of paper.
A motherboard has a number of special sockets that accept various PC components. There are sockets for the microprocessor, sockets for RAM, sockets to provide power, connectors for floppy drives and hard drives, and connectors for external devices such as mice, printers, joysticks, and keyboards. A few components are soldered directly to the motherboard. Between the various devices, the motherboard is filled with tiny wires, called ‘traces,” which electrically link the various components of the PC together.
All motherboards also have multipurpose expansion slots that allow the addition of optional components. There are thousands of different types of optional devices that can be added to a PC, including scanners, modems, network cards, sound cards, and tape backups. The expansion slots allow optional devices to communicate with the PC. The device that connects to the expansion slot is generically called an expansion card, an adapter card or just a card. There are different types of expansion slots for different types of cards.
The position of the expansion slots and external components is very standardized. They have to be. The motherboard is mounted to the box or case, the part of the PC that you actually see. The box needs to have holes that allow devices to access the external connectors. For example, if the motherboard has a connector for a keyboard, there needs to be a hole in the box though which the keyboard plug can be inserted.
Equally important, if the expansion slots allow you to add cards to the PC, then there must also be holes that allow different devices to connect to their cards. Clearly, there must be a certain type of box to go with a certain type, or layout, of motherboard. Fortunately, there are very few different layouts of motherboard, requiring only a few different types of boxes. There will be much more on motherboards covered later.
While you’re out surfing, no web search for motherboard information would be complete without a visit to Tom’s Hardware Guide.