Chapter 1

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The computer system consists of:1. Hardware: Physical Components,

like the system unit ,monitor ,keyboard, mouse , camera, printer … etc.

2. Software: set of instructions that tell the computer what to do and how to do it.

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Computers vary in performance and cost, in size and capabilities

Therefore, there are many types of computers that are used for different purposes.

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The most popular, and not very expensive.

The software that is compatible with the PC depends on the manufacturer of this PC.

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- There are two kinds of PC’s :1) IBM Compatible computers (Windows)

2)Apple computers (Macs OS)

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Portable and Briefcase sized

As powerful as a PC but more expensive

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Portable Hand-held computers.

Does very simple functions, and relatively cheap.

Also called “Notepad”.

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PDA(Personal Digital Assistant):

Small pen controlled, handheld computers

Used to send and receive faxes and emails, play games, Calender

Mobile Phone: electronic telecommunication Device

(SMS, MMS)

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Smart phone:Mobile phone with a

PC-like functionality.(Email, Internet,

Camera, Play music, read document)

Multimedia Player:Allows you to store

digital music/video.

Ex. iPod

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1) CPU(processor)

2) Memory

3) Storage Units

4) Input Devices

5) Output Devices

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-It performs all calculations and determines how fast your computer will run.

- CPU speed is measured by MHZ/GHZ.

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- CPU elements:- Control Unit (CU): responsible for

controlling the sequencing and timing of the other elements making up the CPU.

- Arithmetic Logical Unit (ALU): performs arithmetic and logical operations.

- Registers:

- Buses: collection of wires

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The part of the computer where data and programs are stored temporarily.

1)Random Access Memory (RAM)

2)Read Only Memory (ROM -Booting Up)

3)BIOS

4)Cache memory

5)Video memory

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RAM Electronic memory that

temporarily stores information inside a computer

This memory is volatile, If you do not save the data to the ROM, it will disappear when you turn off the computer

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This memory does not lose information, even when the power is turned off

Once data is programmed into the ROM chip, its contents cannot be altered.

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Store data recently used by the CPU.

Very fast chips, so that to reduce the speed gap between CPU and RAM.

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A port : is a socket on the outside of the system unit that is connected to an expansion board in the inside of the system unit.

1) USB Port

2) Serial Port

3) Parallel Port

4) Network Port

5) Fire Wire

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Computer’s performance: the factors that affect the speed of the CPU processing.

1)RAM2)Hard Disk speed3)Hard Disk space4)Defragmenting Files5)CPU speed6)Number of running applications

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Computers store information in the form of BITS and BYTES.

A BIT is either a 0 or a 1. Grouping 8 BITS, produces a 1 Byte, which

represents the memory unit. Memory capacity is measures by the

number of bytes it can hold.

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Data in the computer is represented using

the Binary System which has only two

digits 0 or 1.

Decimal System has 10 digits (0-9)

Example :

Decimal Binary

5 101

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Memory unitNumber of Bytes

Binary Representation

Byte 1 Byte(8 BITS) 20 Byte

Kilo Byte 1024 Bytes 210 Bytes

Mega Byte 1048576 Bytes 220Bytes

Giga Byte1073741824 Bytes

230 Bytes

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Bit

Byte

KB

GB

MB

TB

TB = 1024 GB

GB =1024 MB

MB = 1024 KB

KB = 1024 Byte

Byte = 8 Bits

Largest Unit

Smallest Unit

Example :

1 TB = 1024 x 1024 = 220 MB

GB= 1024 x 1024 x 1024= 230 BYTE

KB = 1024 x 8= 213 Bits

210

=1024

Devices that save the result of the processed data permanently for later retrieval.

Examples1 .Internal Hard disk

2 .External Hard disk

3 .Floppy Disk

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4. CD-ROM(CD-R , CD-RW)

5. DVD

6. USB Flash Drive

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7. Network Drive

8. Online File Storage

9. Memory Card

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Devices that allow the user to enter data into the computer

1. Keyboard

2. Mouse

3. Trackball

4. Touchpad

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5. Scanners 6. Joystick

7. Microphone

8. Digital Camera

9. Web Camera

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Devices that translate information after being processed into a form the user can understand.

1 .Monitors a. Traditional computer monitors.

b. Flat –Panel Display .

2 .Projectors

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3 .Speakers.

4 .Speech Synthesizer.

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5 .Printers a. Laser Printers .

b. Inkjet .

c. Dot Matrix.

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Touch Screen

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