The Parts of a
Computer Motherboard
Some of the major components of a motherboard.
The main printed
circuit board in a computer is known as the motherboard. Other names for this
central computer unit are system board, main board, or printed wired board (PWB).
The 
motherboard is sometimes shortened to
Mobo.
Numerous major
components, crucial for the functioning of the computer, are attached to the
motherboard. These include the processor, memory, and expansion slots. The
motherboard connects directly or indirectly to every part of the PC.
The type of
motherboard installed in a PC has a great effect on a computer's system speed
and expansion capabilities.
Major Motherboard
Components and Their Functions
A labeled ASRock K7VT4A Pro Mainboard. | Source
Central Processing Unit (CPU)
Also known as the
microprocessor or the processor, the CPU is the computer's brain. It is
responsible for fetching, decoding, and executing program instructions as well
as performing mathematical and logical calculations.
The processor chip
is identified by the processor type and the manufacturer. This information is
usually inscribed on the chip itself. For example, Intel 386, Advanced Micro
Devices (AMD) 386, Cyrix 486, Pentium MMX, Intel Core 2Duo, or iCore7.
If the processor
chip is not on the motherboard, you can identify the processor socket as socket
1 to Socket 8, LGA 775 among others. This can help you identify the processor
that fits in the socket. For example, a 486DX processor fits into Socket 3.
Random Access Memory (RAM)
Random Access
Memory, or RAM, usually refers to computer chips that temporarily store dynamic
data to enhance computer performance while you are working.
In other words, it
is the working place of your computer, where active programs and data are
loaded so that any time time the processor requires them, it doesn't have to
fetch them from the hard disk.
Random access
memory is volatile, meaning it loses its contents once power is turned off.
This is different from non-volatile memory, such as hard disks and flash
memory, which do not require a power source to retain data.
When a computer
shuts down properly, all data located in RAM is returned back to permanent
storage on the hard drive or flash drive. At the next boot-up, RAM begins to
fill with programs automatically loaded at startup, a process called booting.
Later on, the user opens other files and programs that are still loaded in the
memory.
Basic Input/Output System (BIOS)
BIOS stands for
Basic Input/Output System. BIOS is a "read only" memory, which
consists of low-level software that controls the system hardware and acts as an
interface between the operating system and the hardware. Most people know the
term BIOS by another name—device drivers, or just drivers. BIOS is essentially
the link between the computer hardware and software in a system.
All motherboards
include a small block of Read Only Memory (ROM) which is separate from the main
system memory used for loading and running software. On PCs, the BIOS contains
all the code required to control the keyboard, display screen, disk drives,
serial communications, and a number of miscellaneous functions.
The system BIOS is
a ROM chip on the motherboard used during the startup routine (boot process) to
check out the system and prepare to run the hardware. The BIOS is stored on a
ROM chip because ROM retains information even when no power is being supplied
to the computer.
Complimentary Metal Oxide Semiconductor Random Access Memory (CMOS RAM)
A CMOS battery.
Motherboards also
include a small separate block of memory made from CMOS RAM chips which is kept
alive by a battery (known as a CMOS battery) even when the PC’s power is off.
This prevents reconfiguration when the PC is powered on.
CMOS devices
require very little power to operate.
The CMOS RAM is
used to store basic Information about the PC’s configuration for instance:-
·
Floppy disk and hard disk drive types
·
Information about CPU
·
RAM size
·
Date and time
·
Serial and parallel port information
·
Plug and Play information
·
Power Saving settings
Other Important
data kept in CMOS memory is the time and date, which is updated by a Real Time
Clock (RTC).
Cache Memory
L2 cache on an old motherboard.
Cache memory is a
small block of high-speed memory (RAM) that enhances PC performance by
pre-loading information from the (relatively slow) main memory and passing it
to the processor on demand.
Most CPUs have an
internal cache memory (built into the processor) which is referred to as Level
1 or primary cache memory. This can be supplemented by external cache memory
fitted on the motherboard. This is the Level 2 or secondary cache.
In modern
computers, Levels 1 and 2 cache memory are built into the processor die. If a
third cache is implemented outside the die, it is referred to as the Level 3
(L3) cache.
Expansion Bus
PCI slots.
An expansion bus is
an input/output pathway from the CPU to peripheral devices and it is typically
made up of a series of slots on the motherboard. Expansion boards (cards) plug
into the bus. PCI is the most common expansion bus in a PC and other hardware
platforms. Buses carry signals such as data, memory addresses, power, and
control signals from component to component. Other types of buses include ISA
and EISA.
Expansion buses
enhance the PCs capabilities by allowing users to add missing features in their
computers by slotting adapter cards into expansion slots.
Chipsets
A chipset is a
group of small circuits that coordinate the flow of data to and from a PC's key
components. These key components include the CPU itself, the main memory, the
secondary cache, and any devices situated on the buses. A chipset also controls
data flow to and from hard disks and other devices connected to the IDE
channels.
A computer has got
two main chipsets:
·
The NorthBridge (also called the memory controller) is in charge of
controlling transfers between the processor and the RAM, which is why it is
located physically near the processor. It is sometimes called the GMCH, for
Graphic and Memory Controller Hub.
·
The SouthBridge (also called the input/output controller or expansion
controller) handles communications between slower peripheral devices. It is
also called the ICH (I/O Controller Hub). The term "bridge" is
generally used to designate a component which connects two buses.
Chipset
manufacturers include SIS, VIA, ALI, and OPTI.
CPU Clock
The CPU clock
synchronizes the operation of all parts of the PC and provides the basic timing
signal for the CPU. Using a quartz crystal, the CPU clock breathes life into
the microprocessor by feeding it a constant flow of pulses.
For example, a 200
MHz CPU receives 200 million pulses per second from the clock. A 2 GHz CPU gets
two billion pulses per second. Similarly, in any communications device a clock
may be used to synchronize the data pulses between sender and receiver.
A "real-time clock," also called the "system clock," keeps
track of the time of day and makes this data available to the software. A
"time-sharing clock" interrupts the CPU at regular intervals and
allows the operating system to divide its time between active users and/or
applications.
Switches and Jumpers
·
DIP (Dual In-line Package) switches
are small electronic switches found on the circuit board that can be turned on
or off just like a normal switch. They are very small and so are usually
flipped with a pointed object, such as the tip of a screwdriver, a bent paper
clip, or a pen top. Take care when cleaning near DIP switches, as some solvents
may destroy them. Dip switches are obsolete and you will not find them in
modern systems.
·
Jumper pins are small protruding pins on
the motherboard. A jumper cap or bridge is used to connect or short a pair of
jumper pins. When the bridge is connected to any two pins, via a shorting link,
it completes the circuit and a certain configuration has been achieved.
·
Jumper caps are metal bridges that close an
electrical circuit. Typically, a jumper consists of a plastic plug that fits
over a pair of protruding pins. Jumpers are sometimes used to configure
expansion boards. By placing a jumper plug over a different set of pins, you
can change a board's parameters. More of this from : turbofuture.com
