Introduction to Computers
1
1.1 What Is Computer?
 Computer is a programmable, electronic
device that accepts data input, performs
processing operations on that data, and
outputs and stores the results.
2
What Does A Computer Do?
 Computers can perform four general operations:




Input
Processing
Output
Storage
3
1.2 What Is Hardware?
 Hardware is the physical parts of a
computer system.
 Examples:




Keyboard
Mouse
Monitor
Printer
4
Examples of Hardware
Monitor
(output)
Speaker
(output)
Printer
(output)
System unit
(processor,
memory…)
Storage
devices
Scanner
(input)
Keyboard
(input)
Mouse
(input)
(CD-RW,
Floppy, Hard
disk, zip,…)
5
1.3 What is Software
 Software is the instructions, also called
computer programs, that are used to
tell a computer what it should do.
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1.3.1


System Software
The programs that allow a computer to
operate are collectively know as system
software.
Examples:

All operating systems.

Windows 7, Vista, XP

LINUX, UNIX
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1.3.2


Application Software
Application software consists of programs
designed to allow people to perform
specific task.
Examples:

MS Office (Word, Excel, Access..)

Photoshop

Internet explorer
8
1.4. Computer Users

End Users


A person who uses the computer to obtain
information.
Programmer

A person whose primary job responsibilty is
to write, maintain, and test computer
programs.
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1.5 Different types of computers

Six basic categories of computers

Embedded computers

Mobile devices

Personal computers

Midrange servers

Mainframe computers

Supercomputers
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1.5.1 Embedded Computers


A tiny computer embedded into a product
and designed to perform specific tasks.
Examples:




Washing machine
Microwave
Televisions
Cars
11
1.5.2 Mobile Devices


A very small device with some type of
Internet capability.
Examples:




Smart phones
Smart watches
Handheld gaming devices
Portable digital media players
12
1.5.3 Personal Computer


A computer system designed to be used
by one person at a time.
Examples:


Desktop Pcs
Portable computers
13
Desktop PC
14
Portable Computers
15
1.5.4 Midrange Server

A medium-sized computer used to host
programs and data for a small network.
16
1.5.5 Mainframe Computer


A powerful computer used by several
large organizations to manage large
amounts of centralized data.
Examples:




Hospitals.
Universities.
Banks.
Government offices
17
1.5.6 Supercomputer


Supercomputer is the fastest, most
expensive, most powerful type of
computer.
Examples:




Satellites
Weather forecast
Oil exploration
Scientific research
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2.1 Data Types
Data
Text

Number
Image
Audio
Video
Multimedia

The information that contains numbers, text,
images, audio, and video.
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2.2 Data Inside the computers

Bit

Bit Pattern

Byte
20
2.2.1 Bit


A bit is the smallest unit of data that can
be stored in a computer. It is either 1 or 0.
Examples:
1
Or
0
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2.2.2 Bit pattern

A string of bits is called bit pattern

Examples:
100010101
22
2.2.3 Byte

A group of 8 bits.

Examples:
10001011
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2.3 Representing Data

Text

Number

Image

Audio

Video
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2.3.1 Text representation

ASCII (American Standard Code for Information Interchange)
 This code uses 7 bits to represent each symbol.
 Each symbol, can represent up to 128 symbols.
25
2.3.1 Text representation contd.


Extended ASCII
 To make the size of each bit pattern 1 byte (8 bits), and
augmented with an extra 0 at the left hand.
EBCDIC (Extended Binary Coded Decimal Information Code)
 This code was developed by IBM. It uses 8 bit patterns
 Each symbol, can represent up to 256 symbols.
26
2.3.1 Text representation contd.


Unicode
 Unicode uses 16 bits and can represent up to 65,536
symbols.
ISO (International Standard Organizations)
 Developed a code uses 32 bits and can be represented to
4,294,967,296 symbols
27
2.3.2 Numbers

Numbers are represented using the binary
system. In this system, a pattern of bits (a
sequence of 0s and 1s) represents a
number.
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2.3.3 Image

Images today are represented in a
computer by one of two methods.
Image
Bitmap Graphic
Vector Graphic
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2.3.3.1 Bitmap Graphic

An image is divided into a matrix of pixels,
each color pixel is represented its binary
code.
30
2.3.3.2 Vector Graphic

An image is decomposed into a combination
of curves and lines where each curve or line
is represented by a mathematical formula.
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2.3.4 Audio

The analog signal is sampled


The samples are quantized .


(Sampled means measuring the value of signal at equal intervals )
( Quantization means assigning a value to a sample )
The quantized values are changed or coding

( To binary pattern )
32
2.3.5 Video



Video are set of sequential images called frames.
Each image are changed to a set of bit pattern and stored.
The combination to the images representing video
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Coding systems

ASCII (American Standard Code for Information Interchange)

Extended ASCII

EBCDIC (Extended Binary Coded Decimal Information Code)

Unicode

ISO (International Standard Organization)
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Data Storage Unit




KB (Kilobyte)
MB (Megabyte)
GB (Gigabyte)
TB (Terabyte)
=
=
=
=
1,024 bytes
1 million bytes
1 billion bytes
1 trillion bytes
35
3. Number systems


Number system is a way of representing
number.
Examples:
1. Binary number
2. Decimal number
3. Octal number
4. Hexadecimal number
36
3.1 Binary number


Binary number represents all numbers
using just two symbols (0 and 1)
Examples:
0 and 1
37
3.2 Decimal number


Decimal number represents all numbers
using 10 symbols (0 - 9)
Examples:
0 1 2
3 4
5 6 7 8 9
38
3.3 Octal number



Octal number is based on 8 symbols.
Examples: 0 1 2 3 4 5 6 7
Each octal number represented in 3 bit pattern:
Octal
Bit Pattern
Octal
Bit Pattern
0
0 0 0
4
1 0 0
1
0 0 1
5
1 0 1
2
0 1 0
6
1 1 0
3
0 1 1
7
1
1 1
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3.4 Hexadecimal number



Hexadecimal number is based on 16 symbols.
Examples: 0 1 2 3 4 5 6 7 8 9 A B C D E F
Each hexadecimal number represented in 4 bit pattern:
Hexadecimal.
0
1
2
3
4
5
6
7
Bit Pattern
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
Hexadecimal.
8
9
A
B
C
D
E
F
Bit Pattern
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1 40
4. Conversion

Decimal number to Binary number

Binary number to Decimal number
41
4.1 Decimal to Binary conversion
Question :
Convert Decimal number 35 to Binary number
Question :
(35)10 = (

)
2
Examples:
0 
Answer :
1  2  4 
8  17  35
1
0
0
0
(35)10 = ( 100011 ) 2
1
1
42
4.1 Exercises 1
Question :
Convert Decimal number 55 to Binary number
Question :
(55)10 = (

)
2
Examples:
0 
1  3  6  13  27  55
1
Answer :
1
0
1
(55)10 = ( 110111 ) 2
1
1
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4.1 Exercises 2
Question :
Convert Decimal number 49 to Binary number
Question :
(49)10 = (

)
2
Examples:
0 
1  3  6  12  24  49
1
Answer :
1
0
0
(55)10 = ( 110001 ) 2
0
1
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4.2 Binary to Decimal conversion
Question :
Convert Binary number 100011 Decimal number
Question :
(100011)
= (
2
) 10
Examples:

1
0
0
0
1
1
x
x
x
x
x
x
32
16
8
4
2
1
32 +
0
Answer :
+
0
+
(100011)
2
0
+
2
+
= ( 35 ) 10
1
Binary Number
Position value
=
35
45
4.2 Exercise
Question :
Convert Binary number 110001 Decimal number
Question :
(110001)
= (
2
) 10
Examples:

1
1
0
0
0
1
x
x
x
x
x
x
32
16
8
4
2
1
32 + 16 +
Answer :
0
+
(110001)
0
2
+
0
+
= ( 49 ) 10
1
Binary Number
Position value
=
49
46
5. Types of Memory






RAM
SRAM
DRAM
ROM
PROM
EPROM
(Random Access Memory )
(Static Random Access Memory)
(Dynamic Random Access Memory)
(Read Only Memory)
(Programmable Read Only Memory)
(Erasable Programmable Read Only Memory)
47
5.1 RAM

RAM is a volatile memory means the
information is erased if the system is
powered down.
48
5.2 SRAM

SRAM technology uses the flip – flop gates
(a gate with two states: 0 and 1) to hold
data. SRAM is fast abut expensive.
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5.3 DRAM

DRAM technolgy uses capacitors. If
capacitor charged, the state is 1, else 0,
DRAM is slow but cheaper.
50
5.4 ROM

ROM is a nonvolatile memory in which data
or programs have been permanently
stored.
51
5.5 PROM

PROM is a memory chip on which data can
be written only once. Once a program has
been written onto a PROM, it remains there
forever.
52
5.6 EPROM

EPROM is a special type of PROM that can
be erased by exposing it to ultraviolet light.
Once it is erased, it can be reprogrammed.
53
6. Secondary Storage Devices







Floppy Disk
Hard Disk
Optical Disk
CD/DVD
Flash Memory System
Flash Memory Cards
USB Flash Drives
54
6.1 Floppy Disk

Floppy disk is a low-capacity, removable
disk made of flexible plastic.
55
6.2 Hard Disk

A storage system consisting of one or
more metal magnetic disks permanently
sealed inside its drive.
56
6.3 Optical Disc

Optical disc is a type of storage medium
read from and written to using a laser
beam.
57
6.4 CD/DVD

CD (Compact Disc)


CD is an optical disc with a typical storage
capacity of 650 MB.
DVD (Digital Versatile Disc)

DVD is an optical disc with a typical storage
capacity of 4.7 GB.
58
6.5 Flash Memory Systems

Flash memory system is a storage
system that uses flash memory media.
59
6.6 Flash Memory Cards

Flash memory cards is a small, rectangular
flash memory media.
60
6.7 USB Flash Drives

USB (Universal Serial Bus) is a small
storage device that plugs into Pcs USB port
and contains flash memory media.
61
7. Input Devices






Keyboard
Mouse
Electronic Pen
Scanners
Readers
Touch Screen
62
7.1 Keyboard

Keyboard is an input device containing
numerous keys that can be used to input
letters, numbers, and other symbols.
63
7.2 Mouse

Mouse is a common pointing device that
user slides along a flat surface.
64
7.3 Electronic Pen

Electronic pen is an input device that is
used to wrote electronically on the display
screen.
65
7.4 Scanners


Scanner is an input device that reads
printed text and graphics and transfers
them to a computer in digital form.
Examples :


Flatbed Scanners and
Handheld Scanners
66
7.5 Readers

A variety of readers are available to read
the different types of codes and marks
used today.
67
7.5.1 Types of Readers

Barcode readers






Barcode reader is an input device that reads
barcode.
RFID (Radio Frequency Identification)
OMR
(Optical Mark Readers )
OCR
(Optical Character Recognition)
MICR (Magnetic Ink Character Recognition)
Biometric readers
68
7.6 Touch Screen

Touch screen is a display device that is
touched with the finger to issue commands.
69
8.1 Output Devices

Monitor

Display Screen

Printer
70
8.1.1 Monitor

Monitor is display device for a desktop PC.
71
8.1.2 Display Screen

A display device built into a notebook,
handled PC, or other device.
72
8.1.3.1 Printers


Printer is an output device that produces
output on paper.
Examples:



Laser printer
Ink-jet printer
Photo printer.
73
8.1.3.2 Laser Printer

An output device that uses toner powder.
74
8.3.2 Inkjet Printer

An output device that sprays droplets of ink
to produce images on paper.
75
8.1.3.3 Photo Printer

An output device designed for printing
digital photographs.
76
8.2 Communication between
CPU and Input/Output devices
77
8.2 Continued…

What are the technology of connecting
CPU and Input/output ( I/O ) Units?
BY Using controllers.



USB (Universal Serial Bus )
SCSI (Single computer Serial Input )
Fire wire
78
8.2 Continued………

CPU




(Central Processing Unit)
The chip located inside the system unit of a
computer that performs the processing for a
computer.
ALU
FPU
CU
(Arithmetic Logic Unit)
(Floating Point Unit)
(Control Unit)
79
Hardware details
80
9.1 Algorithm


Algorithm is a step by step method for
solving a problem or doing a task.
Examples: (Sum two numbers)
Input: two numbers
Step1: Add to numbers
Step2: Return the result of step 1
End
81
9.2 Flowchart


Flowchart is a pictorial and graphical
representation of an algorithm.
Example : (Sum of two numbers)
82
9.2 Flowchart continued…
Start
Input A,B
Sum=A+B
Print Sum
Stop
83
9.3 Pseudo code


Pseudocode is an English like
representation of an algorithm.
Example :
Begin
input x
input y
sum = x + y
print sum
End
84
10.1 Machine Language

Machine language is a binary-based
language for representing computer
programs that the computer can execute
directly.
85
10.2 Assembly Language

A special program called an assembler is
used to translate symbolic code into
machine language, known as assembly
language.
86
10.3 High Level Language


High level languages are portable to many
different computers.
High
level
languages
share
one
characteristic with symbolic languages:
they must be converted to machine
language.
This
process
is
called
compilation.
87
11.1 What is Network

Network is a collection of computers and
other hardware devices that are connected
together to share hardware, software, and
data.
88
11.1.2 Internet and benefits


The largest and the most well know computer
network, linking millions of computers all over
the world.
Benefits:




Web Browsing
E-mail
Chatting and Entertainment
Communication & business
89
11.2 Types of Networks

LAN (Local Area Network)

MAN (Metropolitan Area Network)

WAN (Wide Area Network)
90
11.2.1 LAN


LAN is a network that connects devices
located in a small geographical area, such as
a home, office building, or school.
Computers are connected via cables
91
11.2.2 MAN


MAN is a network designed to service a
metropolitan area such as a city or country.
Computers are connected via wireless MANs
92
11.2.3 WAN


WAN is a network that connects devices located in
a large geographical area.
Computers are connected via wireless
93
12.1 Operating System

Operating system is a collection of programs that
manage and coordinate the activities taking
place within a computer system.
94
What are benefits of operating system?

Boot Process


Start up computer and load operating files to memory
User interface

Translates the user instruction to control hardware and
feedback of hardware to user
95
12.2 Types of Operating System

Command line Interface

GUI (Graphical User Interface)
96
12.2.1 Command line Interface


A user interface in which commands are
typed on a keyboard.
Examples:



DOS (Disk Operating System)
LINUX
UNIX
97
12.2.2 GUI (Graphical User Interface)

A graphically based interface that allows a
user to communicate instructions to
computer easily.
98
12.2.2 Graphical User Interface
1.
Microsoft Windows
Examples:










Windows 3.1
Windows 3.11
Windows Workgroups (networks)
Windows 95
Windows 98
Windows 2000
Windows Me
Windows vista
Windows XP
Windows 7
99
12.2.2 Graphical User Interface
2.


Apple macchntosk (MAC )
Has a high level of multimedia functions and connectivity
Graphical user interface
100