1
Computer
Organization
ANGELITO I. CUNANAN JR.
Hardware Inside Computer
Case…

A motherboard containing the CPU, memory, and other
components

A hard drive and optical drive (CD or DVD) used for
permanent storage

A power supply with power cords supplying electricity to all
devices inside the case

Adapter cards used by the CPU to communicate with
devices inside and outside the case. All adapter cards
contain microchips, which are most often manufactured
using CMOS (complementary metal-oxide semiconductor)

Cables connecting devices to adapter cards and the
motherboard
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3
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Motherboard…

The largest and most important circuit board in the
computer is the motherboard, also called the main board,
the system board, or the techie jargon term, the mobo.

A device that is not installed directly on the motherboard is
called a peripheral device.
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Ports…

Serves as an interface between the computer and other
computers or peripheral devices.

In computer terms, a port generally refers to
the female part of connection.

Computer ports have many uses, to connect
a monitor, webcam, speakers, or other peripheral devices.
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On-board Ports and
Connectors…

Keyboard Port – (Violet), 6 Pins

Mouse Port – (Green), 6 Pins
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On-board Ports and
Connectors…(continued)

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Parallel Port - commonly used by older printers, transmit data
in parallel, eight bits at a time.
On-board Ports and
Connectors…(continued)

Analog Video Port – VGA (Video Graphics Array)
connector is a three-row 15-pin DE-15 connector.
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Guide…

DE-15 - D-subminiature or D-sub is a common type
of electrical connector.
On-board Ports and
Connectors…(continued)

USB Port - is an industry standard developed in the
mid-1990s that defines the cables, connectors and
communications protocols used in a bus for
connection, communication, and power supply
between computers and electronic devices.
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On-board Ports and
Connectors…(continued)

FireWire Port - (IEEE 1394 port) FireWire is very similar
to Universal Serial Bus (USB). The designers of FireWire
had several particular goals in mind when they
created the standard:

Fast transfer of data, Ability to put lots of devices
on the bus, Ease of use, Hot-pluggable ability,
Provision of power through the cable, Plug-andplay performance, Low cabling cost, Low
implementation cost.
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On-board Ports and
Connectors…(continued)
13
The 6-conductor and 4-conductor alpha FireWire 400 connectors
On-board Ports and
Connectors…(continued)

Network Port - is a number that identifies one side of
a connection between two computers. Computers
use port numbers to determine to which process or
application a message should be delivered.
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On-board Ports and
Connectors…(continued)

Sound Port - that facilitates the input and output
of audio signals to and from a computer under
control of computer programs.
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On-board Ports and
Connectors…(continued)
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
Serial Port - Serial ports were originally intended for input and
output devices such as a mouse or an external modem.

have been mostly outdated by USB ports, and few new computers
today have a serial port.
On-board Ports and
Connectors…(continued)

Game port - is an outdated, legacy port used for
joysticks. This device was superseded by USB in the
21st century.
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On-board Ports and
Connectors…(continued)

S/PDIF (Sony/Philips Digital Interface Format) - ports
are used to connect to external sound equipment
such as a CD or DVD player.
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On-board Ports and
Connectors…(additional)

HDMI - (High-Definition Multimedia Interface) is a compact
audio/video interface for transferring uncompressed video
data and compressed or uncompressed digital audio data
from a HDMI-compliant source device. HDMI is a digital
replacement for existing analog video standards.
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Processor and the Chipset…

Processor or CPU is the chip inside the computer
that performs most of the actual data processing.

Chipset is set of chips on the motherboard that
collectively controls the memory, buses on the
motherboard, and some peripherals.
The processor could not do its job without the
assistance of the chipset.
Processor and the
Chipset…(continued)
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Processor…
Processor Sockets

This socket and the chipset determine which processors a board can
support. A socket will hold either an Intel or AMD processor.

Some older processors were installed on the motherboard in a long
narrow slot, but all processors sold today use sockets.

Also know that Intel makes several Itanium and Xeon processors
designed for servers. These server processors use different sockets than
those listed in the table.
Sockets for Intel processors used for desktop computers (next slide)
Sockets for Intel processors used for desktop computers
Intel Socket
Names
Used by Processor Family
Description
LGA1366 or
Socket B
Core i7
•
•
•
1366 pins that touch pads on the Processor
Works with DDR3 memory
Expected to replace LGA771 and LGA775 sockets
LGA771 or
Socket J
Core 2 Extreme
•
•
•
771 pins that touch pads on the processor
Used on high-end workstations and low-end servers
Works with DDR2 memory on boards that have two
processor sockets
LGA775 or
Socket T
Core 2 Extreme
Core 2 Quad
Core 2 Duo
Pentium Dual-Core
Pentium Extreme Edition
Pentium D
Pentium
Pentium 4
Many Celeron processors
•
•
•
775 lands or pads
Works with DDR3 and DDR2 memory
Most popular Intel socket
Socket 478
Pentium 4
Celeron processors
• 478 holes for pins
• Uses a dense micro PGA (mPGA)
• No longer sold
Socket 423
Pentium 4
• 423 holes for pins
• 39 x 39 SPGA grid
• No longer sold
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Processor…(continued)

Earlier Pentiums used a pin grid array (PGA) socket, with pins aligned in
uniform rows around the socket. Later sockets used a staggered pin
grid array (SPGA), with pins staggered over the socket to squeeze
more pins into a small space. Small pins can easily be bent as the
processor is installed in the socket. Later Intel sockets use a land grid
array (LGA) that uses lands rather than pins.

Zero insertion force (ZIF) sockets - processor sockets have a lever on
the side of the socket this lever is used to lift the processor up and out
of the socket.
Sockets for AMD processors used for desktop computers
AMD Socket
Used by Processor Family
Description
AM3 or AMD3
Phenom II
•
•
938 holes for pins (PGA)
Works with DDR3 memory
AM2+ or AMD2+
Phenom II, Phenom, and Athlon
•
•
•
940 holes for pins (PGA)
Works with DDR2 memory
Faster than AMD2
AM2 or AMD2
Athlon and Sempron
•
•
940 holes for pins (PGA)
Works with DDR2 memory
Socket 754
Athlon and Sempron
•
•
754 holes for pins (PGA)
Works with DDR memory
Socket 940
Athlon
•
•
940 holes for pins (PGA)
Works with DDR memory
Socket 939
Athlon and Sempron
•
•
•
939 holes for pins (PGA)
Works with DDR memory
No longer sold
Socket A
Athlon, Sempron, and Duron
•
•
•
462 holes for pins (PGA)
Works with DDR memory
Rarely sold today
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Chipset…

The fast end of the hub, which contains the graphics and memory
controller, connects to the system bus and is called the hub’s North
Bridge.

The slower end of the hub, called the South Bridge, contains the I/O
controller hub. All I/O devices, except display and memory, connect
to the hub by using the slower South Bridge.
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Chipset…
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Buses and Expansion Slots…
Look on the bottom of the motherboard, and you see a maze of circuits
that make up a bus. These embedded wires carry four kinds of cargo:

Electrical power. Chips on the motherboard require power to function.
These chips tap into a bus’s power lines and draw what they need.

Control signals. Some wires on a bus carry control signals that
coordinate all the activity.
Buses and Expansion Slots
…(continued)
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
Memory addresses. Components pass memory addresses to one
another, telling each other where to access data or instructions. The
number of wires that make up the memory address lines of the bus
determines how many bits can be used for a memory address. The
number of wires thus limits the amount of memory the bus can
address.

Data. Data passes over a bus in a group of wires, just as memory
addresses do. The number of lines in the bus used to pass data
determines how much data can be passed in parallel at one time. The
number of lines depends on the type of processor and determines the
number of bits in the data path. (Remember that a data path is the
part of the bus on which the data is placed; it can be 8, 16, 32, 64, or
more bits wide.)
Buses and Expansion Slots
…(continued)

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PCI (Peripheral Component Interconnect) bus A bus common to
desktop computers that uses a 32-bitwide or a 64-bit data path.
Several variations of PCI exist. One or more notches on a PCI slot keep
the wrong PCI cards from being inserted in the PCI slot.
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Buses and Expansion Slots
…(continued)

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PCI-X The next evolution of PCI is PCI-X, which has had three major
revisions; the latest is PCI-X 3.0. All PCI-X revisions are backward
compatible with conventional PCI cards and slots, except 5-V PCI
cards are no longer supported. PCI-X is focused on technologies that
target the server market; therefore, it’s unlikely you’ll see PCI-X slots in
desktop computers. Motherboards that use PCI-X tend to have several
different PCI slots with some 32-bit or 64-bit slots running at different
speeds. For example, Figure 5-13 shows a motherboard with three
types of slots. The two long green slots are PCI-X; the three white slots
are PCI, and the one offset lime green slot is AGP. The two PCI-X slots
can use most 32-bit and 64-bit PCI or PCI-X cards. PCI-X is being
replaced by PCI Express.
Buses and Expansion Slots
…(continued)

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PCI Express (PCIe) The latest evolution of PCI, which is not backwardcompatible with earlier PCI slots and cards. PCIe slots come in several
sizes including PCIe x1, PCIe x4, PCIe x8, and PCIe x16.
Three PCI Express slots and
three PCI slots on a
motherboard…
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Three types of PCIe slots and
one conventional PCI slot…
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Buses and Expansion Slots
…(continued)

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Motherboard video slots and video cards used the Accelerated
Graphics Port (AGP) standards for many years, but AGP has mostly
been replaced by PCI Express. Even though AGP is a dying
technology, you still need to know how to support it. A motherboard
will have a PCI Express x16 slot or an AGP slot, but not both.
AGP Standards
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Buses and Expansion Slots
…(continued)
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
AMR AND CNR SLOTS

To reduce the total cost of a computer system, some older
motherboards might have a small expansion slot, about the length of
a PCI Express x1 slot. This small slot can be an audio/modem riser
(AMR) slot or a communication and networking riser (CNR) slot (see
Figure 5-20). These small slots accommodate small, inexpensive
expansion cards called riser cards, such as a modem riser card, audio
riser card, or network riser card. (These are not the same riser cards
used in NLX systems or riser cards used to extend an expansion slot.)
Part of a riser card’s audio, modem, or networking logic is on the card,
and part is on a controller on the motherboard. If you see an older
motherboard and it has a short slot beside a PCI or AGP slot, suspect
that it’s a CNR or AMR slot. AMR and CNR slots are rarely used today
and it’s next to impossible to find the cards that fit them.