AIM: INTRODUCTION TO COMPUTER HARDWARES
TIME-80 Mins( 02 Pds)
STEPS:(a) Introduction to computer motherboard and its type.
(b) Major portions/ parts of a motherboard.
TIME-10 MIN
TIME-70 MIN
(a) Introduction to computer motherboard and its type.
TIME-10 MIN
.The motherboard is a printed circuit board that is the foundation of a computer and allows
the CPU, RAM, and all other computer hardware components to function and communicate with each
other.
Below is a graphic illustration of the ASUS P5AD2-E motherboard and some basic explanations of each
of the major portions of the motherboard.
(b) Major portions/ parts of a motherboard.
i)
TIME-70 MIN
Expansion Slots :- Alternatively referred to as a bus slot or expansion port, an expansion
slot is an opening located inside a computer on the motherboard or riser board that allows
additional boards to be connected to it. In this picture, there are three different types of
expansion slots; PCI Express, PCI, and AGP.
ii)
Back panel and I/O connectors :- Below is a picture of the back of a desktop computer and
each of connections or ports. Although your desktop computer's layout may be different, this
diagram dives you a better understanding of where everything connects.
iii)
Heatsink :- A heat sink is an electronic device that incorporates either a fan or a peltier device
to keep a hot component cool. They are of two types: - active and passive.
Active heat sinks utilize power and are usually a fan type or some other peltier cooling device. Such as
fans with ball-bearing motors that often last much longer than sleeve bearings. Sometimes these types of
heat sinks are referred to as a HSF, which is short form of heat sink and fan.
Passive heat sinks are 100% reliable, as they have no mechanical components. Passive heat sinks are
made of an aluminum-finned radiator that dissipates heat through convection. For Passive heat sinks to
work to their full capacity, it is recommended that there is a steady air flow moving across the fins.
iv)
P4 power connector:- A 12V power supply cable like that shown in the picture is used
with motherboards that have an Intel Pentium 4 processor. The P4 cable has two black
wires that serve as a ground and two yellow wires that are +12VDC.
v)
CPU socket:- When referring to a processor, a CPU socket or processor socket is a connection
that allows a computer processors to be connected to a motherboard. For example, the Socket
370 is an example of such a socket
vi)
Northbridge:- Alternatively referred to as the PAC (PCI/AGP Controller) which is an
integrated circuit that is responsible for communications between the CPU interface, AGP, and
the memory. Unlike the Southbridge, the Northbridge is directly connected to these
components and acts like a "bridge" for the Southbridge chip to communicate with the CPU,
RAM, and graphics controller. Today, the Northbridge is a single-chip that is North of the
PCI bus, however, early computers may have had up to three separate chips that made up the
Northbridge.
vii)
Memory slots:- A memory slot, memory socket, or RAM slot is what allows computer
memory (RAM) to be inserted into the computer. Depending on the motherboard, there may be
2 to 4 memory slots (sometimes more on high-end motherboards) The most common types of
RAM are SDRAM and DDR for desktop computers and SODIMM for laptop computers, each
having various types and speeds. In the picture below, is an example of what memory slots may
look like inside a desktop computer. In this picture, there are three open available slots for three
memory sticks.
viii)
SuperI/O:-
Short form of
super input/output, It is an integrated circuit on a
computer motherboard that handles the slower and less prominent input/output devices shown
below. Today, super I/O communicates through the Southbridge and is still used with
computers in order to support older legacy devices.
Computer devices handled by the Super I/O









Floppy disk controller
Game port
Infrared
Intrusion detection
Keyboard and mouse (non-USB)
Parallel port
Real-time clock (RTC)
Serial port (UART)
Temperature sensor and fan speed
ix)
Floppy connector:- A floppy cable is a ribbon cable found in PC computers that allow one or
more floppy disk drives to be connected to a computer. This cable allows a desktop computer
to have two floppy drives connected to one floppy controller.
Because floppy drives do not have a master or slave
jumper, the drives are defined by cable select, which can be identified by looking for the cable twist as
shown in the pictures, most floppy cables also have a red strip along one side of the ribbon cable to
indicate pin one. Today, if any floppy drive is in the computer it would be connected to "Drive A:" and the
end cable connected to the motherboard.
x)
IDE (Short for Integrated Drive Electronics) :-
IDE is more commonly known
as ATA or Parallel ATA (PATA) and is a standard interface for IBM compatible hard drives.
IDE and its updated successor, Enhanced IDE (EIDE), are the most common drive interfaces
found in IBM compatible computers today. Below, is a picture of the IDE connector on the
back of a hard drive, a picture of what an IDE cable looks like, and the IDE channels it
connects to on the motherboard.
xi)
24-pin ATX power connector:- Replacement for the older P8 and P9 AT style connector, this
connector is one of the largest connectors inside your computer that connects the computer
power supply to an ATX style motherboard. As shown to the picture, this 20-pin cable is a
multi-color cable and may be labeled as P1.
Note: with the introduction of ATX-2, this cable is now a 24-pin cable and no longer a 20-pin
cable. As seen in the pictures, the cable has a small clip on the top of the cable that should snap
and hold the cable in place. This cable is also keyed, which means it only connects in one
direction.
A power supply with a 24-pin connector can be used on a motherboard with a 20-pin connector by leaving
the four additional pins disconnected. However, if you have a 24-pin connection on your motherboard all
24-pins need to be connected. If you are using a power supply that does not have a 24-pin connector, you
need to purchase a new power supply.
Warning: When using a connector like that shown above note the arrows pointing to each
other. For the cable to be correctly inserted, the arrows must point to each other.
xii)
4- SATA connections:- Short for Serial ATA, SATA 1.0 was first released in August2001 and
is a replacement for the Parallel ATA interface used in IBM compatible computers. Serial ATA
is capable of delivering 1.5Gbps (150MBps) of performance to each drive within a disk array,
offers backwards compatibility for existing ATA and ATAPI devices. It is a thin, small cable
solution as seen in the picture. This cable helps make a much easier cable routing and offers
better airflow in the computer when compared to the earlier ribbon cables used with ATA
drives.
e-SATA offers many more advantages when compared to other solutions.
For example, it is hot-swappable, supports faster transfer speeds and supports disk drive technologies such
as S.M.A.R.T..
Unfortunately, however, e-SATA does have some disadvantages such as not distributing power through
the cable like USB, which means drives will require an external power source and it only supports a
maximum cable lengths of up to 2m.
xiii)
CMOS
Battery:-
Alternatively
CMOS is
referred
to
short
as
for Complementary
a Real-Time
Clock
Metal-Oxide
(RTC),
Semiconductor.
Non-Volatile
RAM
(NVRAM) or CMOS RAM, CMOS is an on-board semiconductor chip powered by a CMOS
battery inside computers that stores information such as the system time and date and the
system hardware settings for your computer. The picture shows an example of the most
common CMOS coin cell battery used in a computer to power the CMOS memory.
A Motorola 146818 chip was the first RTC and CMOS RAM chip to be used in early IBM computers. The
chip was capable of storing a total of 64 bytes of data. Since the system clock used 14 bytes of RAM, this
left an additional 50 bytes of space that was available for IBM to store system settings. Today, most
computers
have
moved
the
settings
from
a
separate
chip
and
incorporated
them
into
the southbridge or Super I/O chips.
How long does the CMOS battery last?
The standard lifetime of a CMOS battery is around 10 Years. However, this can vary depending on
the use and environment that the computer resides. When the battery fails the system settings and
the date and time will not be saved when the computer is turned off until the battery has been
replaced.
xiv)
ATA RAID:-. Short for Redundant Array of Inexpensive Disks, RAID is an assortment of
hard drives connected and setup in ways to help, protect or speed up the performance of a
computer's disk storage. RAID is commonly used on servers and high performance computers.
Versions of RAID
xv)
System panel connector:- Alternatively referred to as the front panel connector,
the system panel connector is what controls the computer's power button, reset button,
and LED's found on the front of a computer using the system panel cables. The System panel
cables, as shown in the picture are two wire cables that are color coded to identify where they
connect to the motherboard system panel connector. The black or white wire is the ground
(GND) wire and the colored wire is the powered wire. The cables, colors, and connections vary
depending on the computer case and motherboard you have, however, generally include the
cables mentioned below.
Types of system panel cables





HDD LED (IDE LED) - The LED activity light for the hard drive. This is the LED that flashes as
information is being written and read from the Hard drive.
Power LED (PLED) - The LED power light, which indicates when the computer is on, off, or in
Standby.
Power SW (PWRSW) - Controls the power button that allows you to turn on and off the computer.
Reset SW - Handles the Reset button to restart the computer.
Speaker - The internal speaker used to sound the beep noises you hear from your computer when it
is booting.
With most computer motherboards, the system panel cables are connected directly to the motherboard.
Which direction do the system panel cables connect?
The system panel cables are not keyed so can be plugged in any direction. With the exception of the
LED cables, the system panel connector cables can be plugged in any direction. If the LED cables
are plugged in backward, the LED light will not work. Usually with most modern motherboards you
can identify what cable goes where by looking at the motherboard for a + and a - symbol. The
colored wire (powered wire) would connect to the + symbol and a white or black cable (ground)
would connect to the - symbol.
In the above diagram example, copied from a motherboard manual, you can clearly see how each of
these cables connects to the motherboard. For example, in the top left portion for the Power LED
(PLED) the first pin is PLED+, which indicates the colored wire side of the connector connects to
this pin. Keep in mind that how these cables connect vary depending on your motherboard.
xvi)
FWH( Firmwire Hub):-Short for Firm Ware Hub, FWH is part of the Intel Accelerated Hub
Architecture that contains both the system BIOS and integrated video BIOS on one component.
The FirmWare Hub connects directly to the I/O Controller Hub (ICH) without requiring
an ISA bus.
xvii)
The
picture
shows
an
example
of
a
FWH
chip
in
a PLCC.
Southbridge:-The Southbridge is an integrated circuit on the motherboard that is responsible
for the hard drive controller, I/O controller and integrated hardware such as sound card, video
card if present
on
the motherboard, USB, PCI, ISA, IDE, BIOS,
and Ethernet.
The
southbridge gets its name for commonly being South of the PCI bus. It is common for
the northbridge and southbridge to have a heat sink; in addition, the northbridge is usually
slightly larger than the southbridge.
The southbridge handles most of the I/O devices, although less prominent input/output devices, such as a
serial port, keyboard, and non-USB mouse are handled by the super input/output (SIO).
Note: Some newer chipsets are combining the Southbridge and Super I/O chips into a single chip and
referring to this chip as the Super Southbridge chip. Some manufacturers such as NVIDIA and SiS have
even combined the Northbridge, Southbridge, and Super I/O into a single chip.
Note: Newer motherboards are also replacing the northbridge and the southbridge with IHA.
xviii) Serial port::-An Asynchronous port on the computer used to connect a serial device to the
computer and capable of transmitting one bit at a time. Serial ports are typically identified on
IBM compatible computers as COM (communications) ports. For example, a mouse might be
connected to COM1 and a modem to COM2. With the introduction of USB, FireWire, and
other faster solutions serial ports are rarely used . The picture shows the DB9 serial port on the
back of a computer.
You can notice the DB9 serial port is easy to identify. The connection is in the shape of the letter D,
is a male connector, and has 9 pins. Below is a listing of each of the pins located on the DB9
connector, their purpose, and signal name. As can be seen in the above picture pin one is in the
top left and pin 9 is in the bottom right.
PIN
PURPOSE
SIGNAL NAME
1
Data Carrier Detect
DCD
2
Received Data
RxData
3
Transmitted Data
TxData
4
Data Terminal Ready
DTR
5
Signal Ground
Gnd
6
Data Set Ready
DSR
7
Request To Send
RTS
8
Clear To Send
CTS
9
Ring Indicator
RI
xix)
1394 header and USB header:-The 1394 header and USB header is a pin connection
found on a computer motherboard that allow additional 1394 and USB connections to be added
to the computer. For example, if you wanted to add additional USB connections to the front of
your computer a USB add-on could be added into one of the drive baysand connected to the
USB header. The picture shows an example of what the 1394 and USB headers look like on a
computer motherboard.
As can be seen in the picture, both the 1394 and USB headers have nine pins and closely resemble each
other. Every motherboard is different, the 1394 or USB header on your motherboard may only have four
or five pins.
Caution: Plugging a 1394 header cable into the USB header connection or the USB header cable
into a 1394 connection will damage a motherboard. Always consult your motherboard
manufacturer manual before connecting anything to the 1394 or USB header.
Other types of motherboard headers
xx)
S/PDIF
:-
Short
for Sony
and
Phillips
Digital
Interconnect
Format,
the
S/PDIF or SPDIF interface is used to transmit digital audio, in a compressed form, between
audio equipment and home theater systems. The S/PDIF interface can utilize a coaxial cable or
a fiber optic cable to transmit the audio. Common equipment to use this interface
are DVD Players and CD Players, connecting to a home theater system for Dolby Digital or
DTS surround sound. High quality sound cards and laptops also have this connector. In the first
picture to the right, is an example of what the SPDIF connector may look like on your
computer motherboard.
xxi)
CD-IN:- Alternatively referred to as the optical drive audio connector, the CD-IN is a four-pin
connector found on a computer motherboard or sound card that connects an optical drives
audio to the motherboard or sound card audio. The picture shows a black four-pin connector
and an example of what this connector looks like on a computer motherboard.
An example of how this connector could be used in connecting the four pin wire from the back of a CDROM drive to the connection on the motherboard, allowing the user to listen to an audio CD.
xxii)
Jumper:-Jumpers allow the computer to close an electrical circuit, allowing the electricity to
flow certain sections of the circuit board. Jumpers consist of a set of small pins that can be
covered with a small plastic box (jumper block) as shown in the illustration to the right. Below
the illustration, is a picture of what the jumpers may look like on your motherboard. In this
example, the jumper is the white block covering two of the three gold pins. Also, next to the
pins is a silkscreen description of what the pins do, in this case when pins 1-2 are jumped the
computer is operating normal, when 2-3 are jumped it is set into configuration mode, and
when
open the computer will be in recovery mode.
Today, most users will not need to adjust any jumpers on their motherboard or expansion cards. Usually,
you are most likely to encounter jumpers when installing a new drive, such as a hard drive. As can be seen
in the picture below, ATA (IDE) have jumpers with three sets of two pins. Moving a jumper between each
two pins will change the drive from master drive, slave drive, or cable select.
Tip: Some documentation may refer to setting the jumpers to on, off, closed, or open. When a
jumper is on or covering at least two pins it is a closed jumper, when a jumper is off, is covering
only one pin, or the pins have no jumper it is an open jumper.
Caution: When changing the jumpers on any device, the device and your computer needs to be
turned off.
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