The physical components of a computer can be grouped into four categories: the system unit, input devices, output devices, and storage devices. The system unit contains the main components like the chassis, power supply, motherboard, CPU, memory, and expansion slots. The motherboard connects all the components via buses and contains the BIOS chip which allows the computer to boot. Expansion cards add additional features and connect via slots on the motherboard.

1. Computer Hardware
The physical part of a computer

2. Introduction
 The physical parts of a computer are called
hardware. In this chapter, we will examine the
different types of hardware according to four groups:
 The system unit,
 Input devices,
 Output devices,
 Storage devices.

3. The System Unit
All of the main components of a computer

4. Chassis (Case)

5. Power Supply

6. Power Supply

7. Uninterruptible Power Supply (UPS)

8. Mainboard

9. 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.

10. The ROM-BIOS (Read Only Memory-Basic
Input Output System)

11. 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.

12. 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.

13. Expansion Slots
 Expansion slots hold expansion cards (such as a
video card, sound card, or network card) and
connect them to the buses.

14. ATA and ATAPI Interfaces
 ATA (advanced technology attachment) is the real name
for the mass storage device (such as hard disks, solid-
state drives, and CD-ROM drives) interface, frequently
called IDE (integrated drive electronics)or EIDE
(enhanced IDE).

15. Peripheral Connectors

16. Internal Speaker

17. Central Processing Unit (CPU)
 A central processing unit (CPU) or processor is an
electronic circuit that can execute computer
programs. The CPU is one of the most important
components inside your computer. It is like the brain
of your computer, because it performs all the
computer calculations. CPU speed is measured in
gigahertz (GHz) and has an important effect on the
overall speed of your computer.

18. Central Processing Unit (CPU)

19. Memory (RAM)
 RAM (Random Access Memory) is temporary
memory that the computer uses to store applications
and data that are in use, for example, the operating
system, and a word processor or database program.
RAM is called “random access” because any storage
location can be accessed directly. When you create
data such as a letter or a picture, the computer
stores the data in RAM and then copies them to the
hard disk when you save your work.

20. Memory (RAM)

21. Expansion Cards
 An expansion card (also known as an add-on card,
internal card, or interface adapter) is an electronic
board added in a desktop computer to provide or
expand features not offered by the motherboard.
Expansion cards need device drivers to function
properly.

22. Some Types of Expansion Cards
 Video cards
 Sound cards
 Network cards
 TV tuner cards
 Video processing cards
 Modems

23. Graphic card