System Components 1: Muhamed Shej

System components 1
Muhamed Shej
Hardware
The physical parts of a computer are called hardware. We will examine the
different types of hardware according to four groups: the system unit, input
devices, output devices, and storage devices.
The system unit contains the main components of the computer, such as the
mainboard, CPU, RAM, graphics card, hard disk, disk drives, and power supply.
It can also contain optional components such as a sound card or a network
card.
We use input devices to put data into the computer. The most common input
devices are the keyboard and the mouse. Other types of input device are a
scanner, joystick, light pen, touch screen, webcam, and digital camera.
Output devices are the components that display results. A monitor, printer,
plotter, and speaker are all output devices.
Storage devices are used to store data permanently. A hard disk, floppy disk,
CD-ROM, DVD-ROM, zip disk, flash memory, memory cards, and tape cartridge
are examples of storage devices.
The System Unit
All of the main components of a computer are grouped

together in the system unit. For instance, the system unit
includes the computer system’s motherboard (including the
processor), expansion cards (video card, sound card, network
card, etc.), power supply, and items such as hard disks, and
CD-ROM drives, and so on.
1. Chassis (Case)
The chassis is the metal and plastic box that contains the system unit
(mainboard, power supply, cooling equipment, hard drives, memories,
optical drives, and any expansion cards). It protects the system from the
outside world and helps to keep the system unit components cool.
There are some general and more specific classifications regarding all
cases. The first classification is according to one of four basic types:
towers, mid-towers, mini towers, and desktops.
.
Most standalone servers come in large towers, which sit upright and
are generally very large to accommodate a large number of hard
drives, cooling equipment, and dual processors.
Mid-towers are like towers in that they stand upright but are generally
smaller in depth, length, and height.
The vast majority of computers these days are mid-towers or mini
towers.
The fourth class is the desktop. This is a computer that lies flat on the
desk, usually with the monitor on top of it.
2. Power Supply
The power supply is an electrical device
that transforms the standard electricity
supply (115-120 volts AC (alternating
current) in the United States or 220 volts
AC in Europe) into the lower voltages
that computer systems require. Personal
computer power supplies are measured
in watts. They usually range from about
50 watts to 500 watts.
3. Mainbord
The mainboard (also called the motherboard, or system board) is the
biggest board inside your system unit. All the main components of your
computer connect to the mainboard. The CPU, BIOS and chipset are
normally situated on your mainboard along with all the other electronic
components.
The CPU executes computer programs, BIOS contains the first code that
is run by the PC when powered on, and the chipset is a set of specialized
chips that control the flow of data throughout the motherboard.
The storage devices, such as the hard disk and DVD drive, are attached
to the mainboard via data cables. The expansion cards, such as the video
card and RAM modules, are attached to the mainboard via the PCI and
memory slots. Mainboards are getting smaller as the components become
more integrated.
The well-known motherboard manufacturers are AsusTek, Intel, Giga-
Byte, Micro-Star International, MSI, PC Chips, and Tyan Computer.
The ROM-BIOS (Read Only Memory-Basic
Input Output System)
This chip is a special ROM microchip on your computer’s
mainboard. It ensures that the BIOS will always be available
and will not be damaged by disk failures. It also makes it
possible for a computer to boot itself.
Because RAM is faster than ROM, many computer

manufacturers design systems so that the BIOS is copied from
ROM to RAM each time the computer is booted.
.
On PCs, the BIOS software performs the following tasks:

► Checks the information stored in a tiny (64 bytes) amount of memory
located on the CMOS (complementary metal oxide semiconductor)
chip.
► Conducts a power-on self-test (POST) for all the different hardware
components (keyboard, display screen, disk drives, serial
communications) to make sure everything is working properly.
► Displays system settings.
► Loads the operating system from hard disk to RAM.
► Activates other BIOS chips on different cards installed in the
computer.
4. System Buses
A motherboard is the most critical part of a computer system. It consists

of three major components: the BIOS (basic input/output system) chip,
the CPU (central processing unit), and the system buses.
Every component in the computer must be able to communicate with the

CPU through the motherboard. This connection is done via a collection of
copper or gold tracings attached to the motherboard. These tiny wires
are called buses. Buses carry data and control messages between the
components.
.
A motherboard has the following buses connected to it:

► The Power Bus: Power for the system is distributed by the
motherboard via a power bus that is connected to the power supply.
► The Front Side Bus: The front side bus is a special high speed bus. It
is designed especially to connect the CPU to components with which
it must communicate very frequently, such as, RAM and the system’s
video card.
► The Back Side Bus: The back side bus is a special bus that allows
communication between the CPU and the layer-2 cache.
► The Peripheral Component Interface (PCI) Bus: The PCI bus is a
slightly slower bus that connects many optional cards to the
motherboard. Examples include sound cards, network cards, etc.
► The Universal Serial Bus (USB):
► Fireware Bus:
.
The Bus Arbitration (Chipset)

The bus arbitration chipset is an integrated circuit on the motherboard.
It controls how the mainboard buses are used. If two different devices
try to use the same bus at the same time, it can cause a problem. The
bus arbitrator prevents this problem. On a PC, the chipset consists of
two basic parts: the northbridge and the southbridge.
Peripheral Connectors
Many newer motherboards have multiple connectors attached to the side
for connecting peripheral or input/output devices. Examples of these
ports are shown below.

System Components 1: Muhamed Shej

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System components 1

All of the main components of a computer are grouped

Because RAM is faster than ROM, many computer

On PCs, the BIOS software performs the following tasks:

A motherboard is the most critical part of a computer system. It consists

Every component in the computer must be able to communicate with the

A motherboard has the following buses connected to it:

The Bus Arbitration (Chipset)

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