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Introduction to Computers

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1.1What Is Computer?

Computer is a programmable, electronic device that accepts data input, performs processing operations on that data, and outputs and stores the results.

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What Does A Computer Do?

Computers can perform four general operations:

Input Processing Output Storage

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1.2What Is Hardware?

Hardware is the physical parts of a computer system.

Examples:

Keyboard Mouse Monitor Printer

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Examples of Hardware

Printer (output)

Monitor (output) Speaker

(output)

Scanner (input)

Mouse (input)

Keyboard (input)

System unit(processor, memory…)

Storage devices

(CD-RW, Floppy, Hard disk, zip,…)

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1.3 What is Software

Software is the instructions, also called computer programs, that are used to tell a computer what it should do.

1.3.1 System Software

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The programs that allow a computer to operate are collectively know as system software.

Examples: All operating systems. Windows 7, Vista, XP LINUX, UNIX

1.3.2 Application Software

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Application software consists of programs designed to allow people to perform specific task.

Examples: MS Office (Word, Excel, Access..) Photoshop Internet explorer

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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.

1.5 Different types of computers

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Six basic categories of computers Embedded computers Mobile devices Personal computers Midrange servers Mainframe computers Supercomputers

1.5.1 Embedded Computers

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A tiny computer embedded into a product and designed to perform specific tasks.

Examples: Washing machine Microwave Televisions Cars

1.5.2 Mobile Devices

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A very small device with some type of Internet capability.

Examples: Smart phones Smart watches Handheld gaming devices Portable digital media players

1.5.3 Personal Computer

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A computer system designed to be used by one person at a time.

Examples: Desktop Pcs Portable computers

Desktop PC

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Portable Computers

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1.5.4 Midrange Server

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A medium-sized computer used to host programs and data for a small network.

1.5.5 Mainframe Computer

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A powerful computer used by several large organizations to manage large amounts of centralized data.

Examples: Hospitals. Universities. Banks. Government offices

1.5.6 Supercomputer

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Supercomputer is the fastest, most expensive, most powerful type of computer.

Examples:

Satellites Weather forecast Oil exploration Scientific research

2.1 Data Types

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Data

Text Number Image Audio Video

Multimedia The information that contains numbers,

text, images, audio, and video.

2.2 Data Inside the computers

Bit

Bit Pattern

Byte

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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:

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1 1 Or 00

2.2.2 Bit pattern

A string of bits is called bit pattern

Examples:

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1 0 0 0 1 0 1 0 1

2.2.3 Byte

A group of 8 bits.

Examples:

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1 0 0 0 1 0 1 1

2.3 Representing Data

Text

Number

Image

Audio

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2.3.1 Text representation

ASCII (American Standard Code for Information ASCII (American Standard Code for Information Interchange)Interchange) This code uses 7 bits to represent each symbol. Each symbol, can represent up to 128 symbols.

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2.3.1 Text representation contd.

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Extended ASCII 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 EBCDIC (Extended Binary Coded Decimal Information Code) Information Code) This code was developed by IBM. It uses 8 bit

patterns Each symbol, can represent up to 256 symbols.

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Unicode Unicode Unicode uses 16 bits and can represent up to

65,536 symbols.

2.3.1 Text representation contd.

ISO (International Standard Organizations) ISO (International Standard Organizations) Developed a code uses 32 bits and can be

represented to 4,294,967,296 symbols

2.3.2 Numbers

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Numbers are represented using the binary system. In this system, a pattern of bits (a sequence of 0s and 1s) represents a number.

2.3.3 Image

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Images today are represented in a computer by one of two methods.

Image

Bitmap Graphic Vector Graphic

2.3.3.1 Bitmap Graphic

An image is divided into a matrix of pixels, each color pixel is represented its binary code.

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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

(Sampled means measuring the value of signal at equal intervals )

The samples are quantized . ( Quantization means assigning a value to a sample )

The quantized values are changed or coding ( To binary pattern )

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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) = 1,024 bytes MB (Megabyte) = 1 million bytes GB (Gigabyte) = 1 billion bytes TB (Terabyte)= 1 trillion bytes

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3. Number systems

Number system is a way of representing number.

Examples:1. Binary number2. Decimal number3. Octal number4. Hexadecimal number

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3.1 Binary number

Binary number represents all numbers using just two symbols (0 and 1)

Examples:

0 and 1

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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

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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:

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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

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:

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Hexadecimal. Bit Pattern Hexadecimal. Bit Pattern0 0 0 0 0 8 1 0 0 0 1 0 0 0 1 9 1 0 0 12 0 0 1 0 A 1 0 1 03 0 0 1 1 B 1 0 1 14 0 1 0 0 C 1 1 0 05 0 1 0 1 D 1 1 0 16 0 1 1 0 E 1 1 1 07 0 1 1 1 F 1 1 1 1

4. Conversion

Decimal number to Binary number

Binary number to Decimal number

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4.1 Decimal to Binary conversion

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Question : Convert Decimal number 35 to Binary number

Question : (35) = ( )

Examples:

210

35

1 0 0 0 1 1

0 1 2 4 8 17

Answer : (35) = ( 100011 )210

4.1 Exercises 1

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Question : Convert Decimal number 55 to Binary number

Question : (55) = ( )

Examples:

210

55

1 1 0 1 1 1

0 1 3 6 13 27

Answer : (55) = ( 110111 )210

4.1 Exercises 2

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Question : Convert Decimal number 49 to Binary number

Question : (49) = ( )

Examples:

210

49

1 1 0 0 0 1

0 1 3 6 12 24

Answer : (55) = ( 110001 )210

4.2 Binary to Decimal conversion

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Question : Convert Binary number 100011 Decimal number

Question : (100011) = ( )

Examples:

2 10

Answer : (100011) = ( 35 )10

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x x x x x x

11 0 0 0 1 Binary Number

32 16 8 4 2 1 Position value

32 0 0 0 2 1+ + + + + = 35

4.2 Exercise

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Question : Convert Binary number 110001 Decimal number

Question : (110001) = ( )

Examples:

2 10

Answer : (110001) = ( 49 )10

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x x x x x x

11 1 0 0 0 Binary Number

32 16 8 4 2 1 Position value

32 16 0 0 0 1+ + + + + = 49

5. Types of Memory

RAM (Random Access Memory ) SRAM (Static Random Access Memory) DRAM (Dynamic Random Access Memory) ROM (Read Only Memory) PROM (Programmable Read Only Memory) EPROM (Erasable Programmable Read Only

Memory)

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5.1 RAM

RAM is a volatile memory means the information is erased if the system is powered down.

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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.

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5.4 ROM

ROM is a nonvolatile memory in which data or programs have been permanently stored.

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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.

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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.

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6. Secondary Storage Devices

Floppy Disk Hard Disk Optical Disk CD/DVD Flash Memory System Flash Memory Cards USB Flash Drives

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6.1 Floppy Disk

Floppy disk is a low-capacity, removable disk made of flexible plastic.

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6.2 Hard Disk

A storage system consisting of one or more metal magnetic disks permanently sealed inside its drive.

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6.3 Optical Disc

Optical disc is a type of storage medium read from and written to using a laser beam.

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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.

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6.6 Flash Memory Cards

Flash memory cards is a small, rectangular flash memory media.

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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.

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7. Input Devices

Keyboard Mouse Electronic Pen Scanners Readers Touch Screen

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7.1 Keyboard

Keyboard is an input device containing numerous keys that can be used to input letters, numbers, and other symbols.

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7.2 Mouse

Mouse is a common pointing device that user slides along a flat surface.

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7.3 Electronic Pen

Electronic pen is an input device that is used to wrote electronically on the display screen.

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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

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7.5 Readers

A variety of readers are available to read the different types of codes and marks used today.

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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

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7.6 Touch Screen

Touch screen is a display device that is touched with the finger to issue commands.

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8.1 Output Devices

Monitor

Display Screen

Printer

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8.1.1 Monitor Monitor is display device for a desktop PC.

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8.1.2 Display Screen

A display device built into a notebook, handled PC, or other device.

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8.1.3.1 Printers

Printer is an output device that produces output on paper.

Examples: Laser printer Ink-jet printer Photo printer.

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8.1.3.2 Laser Printer

An output device that uses toner powder.

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8.3.2 Inkjet Printer

An output device that sprays droplets of ink to produce images on paper.

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8.1.3.3 Photo Printer

An output device designed for printing digital photographs.

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8.2 Communication between CPU and Input/Output devices

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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

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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 (Arithmetic Logic Unit) FPU (Floating Point Unit) CU (Control Unit)

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Hardware details

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9.1 Algorithm

Algorithm is a step by step method for solving a problem or doing a task.

Examples: (Sum two numbers)

Input: two numbersStep1: Add to numbersStep2: Return the result of step 1End

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9.2 Flowchart

Flowchart is a pictorial and graphical representation of an algorithm.

Example : (Sum of two numbers)

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9.2 Flowchart continued…

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Start

Input A,B

Sum=A+B

Print Sum

Stop

9.3 Pseudo code

Pseudocode is an English like representation of an algorithm.

Example :Begin

input x input y sum = x + y print sum

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10.1 Machine Language

Machine language is a binary-based language for representing computer programs that the computer can execute directly.

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10.2 Assembly Language

A special program called an assembler is used to translate symbolic code into machine language, known as assembly language.

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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.

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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.

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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

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11.2 Types of Networks

LAN (Local Area Network)

MAN (Metropolitan Area Network)

WAN (Wide Area Network)

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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

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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

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11.2.3 WAN

WAN is a network that connects devices located in a large geographical area.

Computers are connected via wireless

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12.1 Operating System

Operating system is a collection of programs that manage and coordinate the activities taking place within a computer system.

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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

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12.2 Types of Operating System

Command line Interface

GUI (Graphical User Interface)

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12.2.1 Command line Interface

A user interface in which commands are typed on a keyboard.

Examples: DOS (Disk Operating System) LINUX UNIX

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12.2.2 GUI (Graphical User Interface)

A graphically based interface that allows a user to communicate instructions to computer easily.

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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 connectivityGraphical user interface

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