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This section discusses the subject of
motherboard technology. Knowledge of the motherboard, also
called the system board or main board, is crucial because it is the
nerve center of the computer system. Everything else in the system
plugs into it, is controlled by it, and depends on it to communicate
with other devices on the system. The system board is the largest of
the printed circuit boards and every system has one. It
generally houses the CPU, the controller circuitry, the bus, RAM,
expansion slots for additional boards, and ports for external devices.
In addition, it contains the CMOS and other ROM BIOS and support chips
providing varied functionality. If the computer is a desktop type, the
system board is generally located at the bottom of the computer's
case. If the computer is a tower-configuration case, the system board
is mounted vertically along one side. All components relating to the
system unit connect directly to the system board. External devices
such as the mouse, keyboard, or monitor would not be able to
communicate with the system unit without the system board.
Printed circuit boards are constructed from sheets of fiberglass.
They are covered with sockets and various electronic parts, including
different kinds of chips. A chip is made up of a very small circuit
board etched on a square of silicon, a material with the same chemical
structure as common sand. Chips vary in size, but many are roughly the
size of a postage stamp. A chip is also referred to as a semiconductor
or integrated circuit. The individual wires and hand-soldered
connectors used in older system boards are replaced today by aluminum
or copper traces printed on circuit boards. This improvement has
significantly saved the amount of time spent on building a PC and has
reduced the cost, both for the manufacturer and the consumer. Figure
Motherboard Form Factors Beyond describing motherboards according to the form factor, they are sometimes described according to the type of microprocessor interface (socket) they present. Motherboards can be described as Socket 7, Socket 370, Socket 423, Socket 478, Slot 1, and so on. Slot 1 is first generation ATX, while single Socket 370 is second generation ATX. Sockets and Slots are discussed later in this chapter, under the section "The CPU". Similarly, a motherboard can sometimes be described as
dual-processor or single-processor
Motherboard Components
There are many manufacturers of chipsets. Intel currently produces
some of the fastest chipsets. Use Table
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shows a
motherboard with all of the installed components.
summarizes the distinguishing features of an ATX motherboard, while
Table 
gives a general summary of the motherboard form factors in use today.
,
depending on whether it can use only one or two processors
concurrently. While most motherboards support a single processor, some
have dual processors. Because the need for processing power continues
to grow, single processors are not always able to meet the demand,
especially in corporate networking environments. Dual-processor boards
are a welcome development, since some advanced network operating
systems (Windows 2000, for example) are now designed to take
advantages of multiple processors.
for more information about
major chipset manufacturers and what they offer. A summary description
of the other motherboard components is in Table
.
