computer basic knowledge

7/24/2019 Computer Basic Knowledge

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Computer BasicsPREPARED BYROHIT UPADHYAY


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What is a Computer?

A computer is an electronic device, operating

under the control of instructions (software)

stored in its own memory unit, that can accept

data (input), manipulate data (process), andproduce information (output) from the

processing. Generally, the term is used to

describe a collection of devices that functiontogether as a system.


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Devices that comprise a computer system

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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What does a Computer do?

Computers can perform four general

operations, which comprise the information

processing cycle.

Input

Process

Output

Storage


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Data and Information

All computer processing requires data, which is acollection of raw facts, figures and symbols, such asnumbers, words, images, video and sound, given to the

computer during the input phase.

Computers manipulate data to create information.Information is data that is organized, meaningful, anduseful.

During the output Phase, the information that has beencreated is put into some form, such as a printed report.

The information can also be put in computer storage forfuture use.


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Why is a Computer so powerful?

The ability to perform the information processingcycle with amazing speed.

Reliability (low failure rate).

Accuracy. Ability to store huge amounts of data and

information.

Ability to communicate with other computers.


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How does a Computer know what to

do?

It must be given a detailed list of instructions, called acompute programor software, that tells it exactly

what to do.

Before processing a specific job, the computerprogram corresponding to that job must be stored in

memory.

Once the program is stored in memory the compute

can start the operation by executing the program

instructions one after the other.


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What are the primary components of a

Computer ?

Input devices.

Central Processing Unit(containing the control unit and

the arithmetic/logic unit). Memory.

Output devices.

Storage devices.


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Types of Computer Systems


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Microcomputer Systems

Personal Computer(PC)microcomputer foruse by an individual.

Professional Workstationa powerful,networked PC for business professionals.

Laptopsmall, portable PC.


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Network Servermore powerfulmicrocomputers that coordinate

telecommunications and resource sharing in

small local area networks and Internet and

intranet websites.

Computer Terminalsdepend on servers forsoftware, storage and processing power.


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Network Computerslow-cost, sealedmicrocomputers with no or minimal disk

storage that are linked to the network.

Information Applianceshand-heldmicrocomputer devices.


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Hardware Organized by System

Functions

Input Devicesconvert data into electronic formfor direct entry or through a telecommunications

network into a computer system.

Processing Componentsprimarily the CentralProcessing Unit (CPU)

Arithmetic-Logic Unit(ALU) - perform arithmetic andlogic functions required to execute software

instructions.


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Hardware Organized by System

Functions

Output Devicesconvert electronic information producedby the computer system into human-intelligible form forpresentation to end users.

Storage Devicesstore data and software instructionsneeded for processing.

Control Componentsprimarily the CPUs Control Unitwhich interprets software instructions and transmitsdirections that control the activities of the othercomponents of the computer system.


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Computer Processing Speeds

Millisecondthousandth of a second

Microsecondmillionth of a second

Nanosecondbillionth of a second

Picosecondtrillionth of a second


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Computer Clock Speeds

MIPSmillion instructions per second

Megahertz(MHz)millions of cycles persecond

Gigahertz(GHz)billions of cycles per second


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Input Devices

Keyboard.

Mouse.


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The KeyboardThe most commonly used input device is the keyboard on

which data is entered by manually keying in or typing

certain keys. A keyboard typically has 101 or 105 keys.


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The Mouse

Is a pointing device which is used to control the movement of a

mouse pointer on the screen to make selections from the

screen. A mouse has one to five buttons. The bottom of the

mouse is flat and contains a mechanism that detectsmovement of the mouse.


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The Central processing Unit

The central processing unit (CPU) contains electronic circuits

that cause processing to occur. The CPU interprets instructions

to the computer, performs the logical and arithmetic processing

operations, and causes the input and output operations to

occur. It is considered the brainof the computer.

Control Unit- ALU


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Memory

Memory also called Random Access Memory or RAM

(temporary memory) is the main memory of the computer. It

consists of electronic components that store data including

numbers, letters of the alphabet, graphics and sound. Any

information stored in RAM is lost when the computer is turned

off.

Read Only Memory or ROMis memory that is etched on a chip

that has start-up directions for your computer. It is permanent

memory.


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Amount of RAM In Computers

The amount of memory in computers is typicallymeasured in kilobytes or megabytes. One kilobyte(K or KB) equals approximately 1,000 memorylocations and one megabyte (M or MB) equalsapproximately one million locations A memorylocation, or byte, usually stores one character.

Therefore, a computer with 8 MB of memory can

store approximately 8 million characters. Onemegabyte can hold approximately 500 pages oftext information.


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Output Devices

Output devices make the information resulting

from the processing available for use. The two

output devices more commonly used are the

printerand the computer screen.

The printer produces a hard copy of your output,

and the computer screen produces a soft copy of

your output.


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Storage Devices

Auxiliary storage devices are used to store

data when they are not being used in

memory. The most common types of auxiliarystorage used on personal computers are

floppy disks, hard disks and CD-ROM drives.


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Floppy Disks

A floppy disk is a portable, inexpensive

storage medium that consists of a thin,

circular, flexible plastic disk with amagnetic coating enclosed in a square-

shaped plastic shell.


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Compact Discs

A compact disk (CD), also called an optical disc, is aflat round, portable storage medium that is usually

4.75 inch in diameter.

A CD-ROM (read only memory), is a compact discthat used the same laser technology as audio CDs

for recording music. In addition it can contain other

types of data such as text, graphics, and video.

The capacity of a CD-ROM is 650 MB of data.


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Peripherals Advice


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Storage Capacities

Kilobyte(KB)one thousand bytes

Megabytes(MB)one million bytes

Gigabytes(GB)one billion bytes Terabytes(TB)one trillion bytes

Petabytes(PB)one quadrillion bytes


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RAM vs. ROM

Random Access Memory(RAM)eachmemory position can be both sensed and

changed

Read Only Memory(ROM)can be read butnot erased or overwritten


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ASCII Codes


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What is Software?

Definition:

Various kinds of programs used to operatecomputers and related devices.


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Types of Software


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Types of Software

Application Software- performs informationprocessing tasks for end users.

System Softwaremanages and supportsoperations of computer systems and

networks.


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Application Software

General-Purposeprograms that performcommon information processing jobs for end

users.

Application-Specificsupport specificapplications of end users in business and

other fields.


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General-Purpose Application

Software

Software Suites Web Browsers Electronic Mail

Word Processing Spreadsheets Database Managers

Presentation Graphics Personal Information Managers Groupware


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Software Suites


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The Early Period: Up to 1940

3,000 years ago: Mathematics, logic, and numericalcomputation.

Important contributions made by the Greeks,

Egyptians, Babylonians, Indians, Chinese, andPersians.

1614: Logarithms

Invented by John Napier to simplify difficultmathematical computations.

Around 1622: First slide rule created.


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The Early Period: Up to 1940 (continued)

1672: The Pascaline

Designed and built by Blaise Pascal

One of the first mechanical calculators

Could do addition and subtraction

1674: Leibnitzs Wheel

Constructed by Gottfried Leibnitz

Mechanical calculator Could do addition, subtraction, multiplication, and

division


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The Pascaline: One of the Earliest Mechanical Calculators


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1801: The Jacquard loom Developed by Joseph Jacquard Automated loom

Used punched cards to create desired pattern 1823: The Difference Engine

Developed by Charles Babbage Did addition, subtraction, multiplication, and

division to 6 significant digits Solved polynomial equations and other complex

mathematical problems


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1823: The Difference Engine

Developed by Charles Babbage

Capabilities:

Addition, subtraction, multiplication, and division to 6

significant digits.

Solve polynomial equations and other complexmathematical problems.


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Drawing of the Jacquard Loom


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1830s: The Analytic Engine

Designed by Charles Babbage

More powerful and general-purpose

computational machine Components were functionally similar to the four

major components of todays computers Mill (modern terminology: arithmetic/logic unit)

Store (modern terminology: memory) Operator (modern terminology: processor)

Output (modern terminology: input/output)


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1890: U.S. census carried out with programmablecard processing machines

Built by Herman Hollerith

These machines could automatically read, tally,and sort data entered on punched cards


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The Birth of Computers: 19401950

Development of electronic, general-purposecomputers

Did not begin until after 1940 Was fueled in large part by needs of World War II

Early computers Mark I ENIAC

ABC system Colossus Z1


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Photograph of the ENIAC Computer

h i h f


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The Birth of Computers:

19401950

Stored program computer model Proposed by John Von Neumann in 1946 Stored binary algorithm in the computers

memory along with the data Is known as the Von Neumann architecture Modern computers remain, fundamentally, Von

Neumann machines

First stored program computers EDVAC EDSAC


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The Modern Era: 1950 to the Present

First generation of computing (1950-1959)

Used vacuum tubes to store data and programs

Each computer was multiple rooms in size

Computers were not very reliable

Th M d E 1950 h P


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(continued)

Second generation of computing (1959-1965)

Replaced vacuum tubes by transistors and

magnetic cores Dramatic reduction in size Computer could fit into a single room

Increase in reliability of computers

Reduced costs of computers High-level programming languages

The programmer occupation was born

Th M d E 1950 h P


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(continued)

Third generation of computing (1965-1975)

Used integrated circuits rather than individual

electronic components

Further reduction in size and cost of computers

Computers became desk-sized

First minicomputer developed

Software industry formed

Th M d E 1950 t th P t


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(continued)

Fourth generation of computing (1975-1985)

Reduced to the size of a typewriter

First microcomputer developed

Desktop and personal computers common

Appearance of Computer networks

Electronic mail User-friendly systems (Graphical user interfaces)

Embedded systems


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The Altair 8800, the Worlds First Microcomputer



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(continued)

Fifth generation of computing (1985-?)

Recent developments

Massively parallel processors Handheld devices and other types of personal digital

assistants (PDAs)

High-resolution graphics

Powerful multimedia user interfaces incorporating sound,voice recognition, touch, photography, video, and

television



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(continued)

Recent developments (continued)

Integrated global telecommunications

incorporating data, television, telephone, FAX, theInternet, and the World Wide Web

Wireless data communications

Massive storage devices

Ubiquitous computing


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Computer Software

Computer software is the key toproductive use of computers. Software

can be categorized into two types:

Operating system software

Application software.


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Operating System Software

Operating system software tells the computer how toperform the functions of loading, storing and executing anapplication and how to transfer data.

Today, many computers use an operating system that has agraphical user interface (GUI) that provides visual clues suchas icon symbols to help the user. Microsoft Windows 98is awidely used graphical operating system. DOS (Disk

Operating System) is an older but still widely used operatingsystem that is text-based.


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Application Software

Application Software consists of programs thattell a computer how to produce information.

Some of the more commonly used packages

are:

Word processing

Electronic spreadsheetDatabase

Presentation graphics


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Computers and software Application softwareis designed to solve a specific

problem

System softwareprovides a general programmingenvironment

Operating system is a subset of the system software

Provide functions used by the application software

Provides the mechanisms for application software to

sharethe hardware in an orderly fashion Sharing increases the overall performance by allowing different

application software to use different parts of the computer at

the same time, decreasing the time to execute a collection of

programs and increase overall system performance


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System Software Runtime system for a programming language

C libraries runtime

Standard input/output (I/O) libraryprocedures to performbuffered input/output on a stream of data

The math libraryfunctions to perform various mathematicalfunctions

Graphics librariesfunctions to render images on a bitmappeddisplay

Window systemsoftware that provides a virtualterminal to an application program


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INTRODUCTION TO COMPUTERNETWORKS

Introduction to Computer Networks


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Computer Networks

Computer network connectstwo or more autonomouscomputers.

The computers can begeographically locatedanywhere.



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LAN, MAN & WAN

Network in small geographical Area (Room, Building or aCampus) is called LAN (Local Area Network)

Network in a City is call MAN (Metropolitan AreaNetwork)

Network spread geographically (Country or across Globe)is called WAN (Wide Area Network)



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Applications of Networks

Resource SharingHardware (computing resources, disks, printers)

Software (application software)

Information Sharing

Easy accessibility from anywhere (files, databases)

Search Capability (WWW)

Communication

EmailMessage broadcast

Remote computing



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Network Topology

The network topologydefines the way in whichcomputers, printers, andother devices areconnected.A network topologydescribes the layout of thewire and devices as well asthe paths used by datatransmissions.



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Bus Topology

Commonly referred to as alinear bus, all the devices ona bus topology are connected

by one single cable.



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Star & Tree TopologyThe star topology is the most commonlyused architecture in Ethernet LANs.

When installed, the star topologyresembles spokes in a bicycle wheel.

Larger networks use the extended star

topology also called tree topology. Whenused with network devices that filterframes or packets, like bridges, switches,and routers, this topology significantlyreduces the traffic on the wires bysending packets only to the wires of the

destination host.



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Ring TopologyA frame travels around the ring, stopping ateach node. If a node wants to transmit data,it adds the data as well as the destinationaddress to the frame.

The frame then continues around the ring

until it finds the destination node, whichtakes the data out of the frame.

Single ring All the devices on thenetwork share a single cable

Dual ring The dual ring topologyallows data to be sent in bothdirections.



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Mesh Topology

The mesh topology connects alldevices (nodes) to each other forredundancy and fault tolerance.

It is used in WANs to interconnect

LANs and for mission criticalnetworks like those used by banksand financial institutions.

Implementing the mesh topology isexpensive and difficult.



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Network Components

Physical Media

Interconnecting Devices

Computers

Networking Software

Applications



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Networking Media

Networking media can bedefined simply as the meansby which signals (data) aresent from one computer to

another (either by cable orwireless means).



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Networking Devices

HUB, Switches, Routers, WirelessAccess Points, Modems etc.



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Computers: Clients and Servers

In a client/server networkarrangement, networkservices are located in adedicated computer whoseonly function is to respond tothe requests of clients.

The server contains the file,print, application, security,and other services in acentral computer that is

continuously available torespondto client requests.



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Applications

E-mail

Searchable Data (Web Sites)

E-Commerce

News Groups

Internet Telephony (VoIP)Video Conferencing

Chat Groups

Instant Messengers

Internet Radio

LAN Technologies


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Ethernet BUS Topology

Repeater

LAN Technologies


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Ethernet STAR Topology

Hub


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Classification of computers

Classification ofcomputers

On the basis of

purpose

General purposecomputers

Specific purposecomputers

On the basis of

principles ofoperation

Analog computers Digital computers

Hybrid computers

On the basis of

size and speed

Micro computers Mini computers

Main framecomputers

Super computers


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Classification of computers according to purpose

General purpose computers:A general purpose computers is designed toperform all the needs of the society. Thesecomputers have the ability to storenumerous programs.

These computers can be used for various

applications, ranging for variousapplications, ranging from scientific as wellas business purpose.

Classification of computers according to


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Classification of computers according to

purpose

Specific purpose computersThese computers are designed to handle

problem or to perform a single specific task.

A set of programs are built into the machineand hence cannot perform other types oftask. The computers used for airlinereservations', satellite tracking, and air

traffic control are specific purposecomputers.

Classification of computers based on the


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Classification of computers based on the

principles of operation

Analog computers

Analog computers operates by measuring

physical units such as voltage, pressure,

temperature, speed etc. These computers donot deal directly with numbers.

Analog computers are used for scientific and

engineering purposes.

i i l


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Digital computers

Digital computer: computer that operates with numerical

information or non-numerical information,represented in a digital form is known as digital

computer. These computers operate on binary values 0 and

1.

Analog quantities must be converted into digital

quantity before processing it. The output will also be in digital.

b id


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Hybrid computers

The hybrid computers combines analog and digitalcapabilities.

The user can process both analog and digital data. These computers can take either analog or digital data

and gives the result as per requirement through specialdevices.

A converter is used to convert analog data into digitaldata and vice-versa.e.g., ROBOT is the best example ofhybrid computer.

These computers are used for scientific applications,various field of engineering and in industrial controlprocess.

Classification of computers based on size


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Classification of computers based on size

and speed

Based on size and speed, we can divide

computers into four major categories:

1. Micro computers

2. Mini computers

3. Main frame computers

4. Super computers

L d S t Vi


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Layered System View

Clients, partners, customers

Intranet

Extranet

Internet

Corporate members

Global society competitors

Internets and Extranets


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Internets and Extranets

Intranets Private network within an organization

Provides information to employees

Extranets

Private network that connects organizations Used to allow suppliers and others access

Firewalls

Security system

Protects against external threats

Page 257

Internet Introduction


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Internet Introduction

Internet: The internet is a global network of

interconnected networks, connecting private,public and university networks in one cohesive

unit.

Intranet: An intranet is a private enterprise

network that uses internet and web technologiesfor information gathering and distribution within

an organization.

Extranet: An extranet is a community of interestcreated by extending an intranet to selectedentities external to an organization.

Th I t t


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The Internet

The internet A network of networks

The internet transmits data from one computer(called a host) to another

Internet networks Linked networks that work much the same way --

they pass data around in packets, each of which

carries the addresses of its sender and receiver

H


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Have a

nice day

Encryption

software

running onsending

computer

Decryption

software

running on

Receiving

computer

E%$&:}{|

Have a

nice day

What is the Internet


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What is the Internet

The Internet connects millions of servers.

I t t d E t t


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Intranets and Extranets

Intranet An internal corporate network built using Internet and

World Wide Web standards and products that allows

employees of an organization to gain access to

corporate information

Extranet A network based on Web technologies that links

selected resources of the intranet of a company with itscustomers, suppliers, or other business partners

I t t d E t t


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Intranet A within-organization computer network that uses

Internet technologies to communicate

Extranet Uses Internet technologies to facilitate

communication and trade between an organizationand its business partners, such as suppliers



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Internet, intranet, and extranet potential for productivity enhancement

The Internet


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The Internet

The internet A network of networks

The internet transmits data from one

computer (called a host) to another Internet networks

Linked networks that work much the same way-- they pass data around in packets, each ofwhich carries the addresses of its sender andreceiver


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How the Internet Works


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How the Internet Works Transport control protocol (TCP)

A protocol that operates at the transport layer andis used in combination with IP by most Internetapplications

Backbone

An Internet high-speed, long distancecommunications links (like a bus; wire thatconnects nodes)

Uniform resource locator (URL) An assigned address on the Internet for each

computer E.g., http://www.yorku.ca/

Domain Affiliations


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Domain Affiliations

arts cultural and entertainment activities

com business organizations

edu educational sites

firm businesses and firms

gov government sites

info information service providersmil military sites

nom individuals

net networking organizations

org organizationsrec recreational activities

store businesses offering goods for purchase

web entities related to World Wide Web activities

net networking organizations

Access to the Internet


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Access to the Internet

LAN servers Local servers can provide access to the Internet through normal

connections (e.g., Ethernet)

Serial line internet protocol (SLIP) and

Point-to-point protocol (PPP) Communications protocol software that transmits packets over

telephone lines, allowing dial-up access to the Internet

Connection via an on-line service

Examples are America Online and Microsoft Network. Theseservices usually require sign-up procedures

Three Ways to Access the


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Three Ways to Access the

Internet

Schematic


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Internet Service Providers


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Internet Service Providers

Internet service provider (ISP) Any company that provides individuals or

companies with access to the Internet

Thousands of providers including largecommunications companies

Need an account with the ISP and software thatlinks with TCP/IP

The World Wide Web


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The World Wide Web

World Wide Web A collection of tens of thousands of independently-

owned computers that work together as one in an

Internet service

WWW Terminology


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WWW Terminology

Home page The cover page for a Web site that has graphics, titles,

coloured text, etc.

Hypermedia Tools that connect the data on Web pages, allowing

users to access topics in whatever order they wish

Hypertext markup language (HTML) The standard page description language for Web pages



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Intranet An internal corporate network built using Internet

and World Wide Web standards and products that

allows employees of an organization to gain access

to corporate information Extranet

A network based on Web technologies that linksselected resources of the intranet of a company

with its customers, suppliers, or other business

partners

Intranet


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A network based on TCP/IP protocols (an internet) belonging to an

organization, usually a corporation, accessible only by theorganization's members, employees, or others withauthorization.

An intranet's Web sites look and act just like any other Web sites,but the firewall surrounding an intranet fends off unauthorized

access.

Like the Internet itself, intranets are used to share information.

Secure intranets are now the fastest-growing segment of the

Internet because they are much less expensive to build and

manage than private networks based on proprietary protocols.

Extranet


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A new buzzword that refers to an intranet that is partiallyaccessible to authorized outsiders.

Whereas an intranet resides behind a firewall and is accessible onlyto people who are members of the same company ororganization, an extranet provides various levels of accessibilityto outsiders. You can access an extranet only

if you have a valid username and password, and your identitydetermines which parts of the extranet you can view.

Extranets are becoming a very popular means for business partners

to exchange information.

What is Wireless


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What is Wireless Now the term is used to describe modern wireless

connections such as those in cellular networks and

wireless broadband Internet. In modern usage,

wireless is a method of communication that uses

low-powered radio waves to transmit databetween devices.

Wireless refers to communication without cablesor cords, chiefly using radio frequency and

infrared waves.


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"Wifi" means "wireless fidelity". The term"wifi" refers to certain kinds of wireless local

area networks, or WLAN (as opposed to LAN,

or computers that are networked togetherwith wires).

Internet


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Internet

The internet is a worldwideinterconnection of many differentcomputers and networks.

The internet allows users toefficiently share information,

programs and equipments and tocommunicate with each other.


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The internet was originally developed bythe department of defense and thenational science foundation.

Each internet computer is called a host,and is independent. Its operators can choose which internet

services to use and which local services

to make available to the global internetcommunity.

Advantages of extranet


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Advantages of extranet

Exchange large volumes of data using Electronic DataInterchange (EDI)

Share product catalogs exclusively with wholesalers or those"in the trade"

Collaborate with other companies on joint developmentefforts

Jointly develop and use training programs with othercompanies

Provide or access services provided by one company to agroup of other companies, such as an online bankingapplication managed by one company on behalf of affiliatedbanks

Share news of common interest exclusively

Disadvantages of extranet


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Disadvantages of extranet

Extranets can be expensive to implement and maintain withinan organization (e.g.: hardware, software, employee trainingcosts)

Security of extranets can be a big concern when dealing with

valuable information. System access needs to be carefullycontrolled to avoid sensitive information falling into the wronghands.

Extranets can reduce personal contact (face-to-face meetings)with customers and business partners. This could cause a lack

of connections made between people and a company, whichhurts the business when it comes to loyalty of its businesspartners and customers.

Wireless technologies


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Wireless technologies

Bluetooth, WiFi and WiMAX are wirelesstechnologies which allow devices to inter-

connect and communicate with each other.

Radio waves are electro magnetic waves andhave different frequencies. These technologies

are radio frequencies. Similar to the analogue

radio, or FM radio.


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Bluetoothworks on 2.45GHz frequency.

WiFi works in two frequency bands2.4GHz and 5GHz.

Wi-MAX- Wi MAX is Worldwide Interoperability for MicrowaveAccess works in two frequency bands, 2 -

11GHz and 10 - 66GHz.

Bluetooth


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Bluetooth

Named after the Danish king, Harold Bluetooth, was the first to emerge, severaldevices like mobile phones, pdas,headsets, keyboards, mice, medicalequipment and even cars now come withthis feature.

D t it l t f t


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Due to its low cost, manufacturers are

willing to implement this technology inmost devices. It is designed for short

range communications with a range of

about 10m. As a result, it consumes lesspower and are suited for very small

battery powered devices and portable

devices.


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Problems associated when devices

communicate via infrared or cables

are removed. Infrared requires a lineof sight, blue tooth only needs to be

in reasonable vicinity.


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As cables are not required, it would

be less cumbersome carrying apersonal blue tooth device and

space would be less cluttered.


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As blue tooth devices

automatically communicate witheach other, it requires very little

from the user.

Bluetooth allows for a wireless

Personal Area Network (PAN) withit's short range.

Wi - fi


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Wi fi

WiFi or Wireless Fidelity, has a range of about100m and allows for faster data transfer ratebetween 10 - 54Mbps. There are threedifferent wireless standards under WiFi,

802.11a, 802.11b and 802.11g. 802.11 beingthe wireless standard set by The Institue ofElectrical and Electronic Engineers (IEEE). WiFiis used to create wireless Local Area Networks

(WLAN).

The most widely used standard is 802.11band 802 11g is expected to grow rapidly
http://standards.ieee.org/wireless/index.htmlhttp://standards.ieee.org/wireless/index.htmlhttp://standards.ieee.org/wireless/index.html


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and 802.11g is expected to grow rapidly.These two standards are relatively

inexpensive and can be found providingwireless connectivity in airports, railwaystations, cafes, bars, restaurants and otherpublic areas.

The main difference between the two is thespeed. 802.11b has data transfer rate ofupto 11Mbps and 802.11g has a rate of upto

54Mbps. 802.11g is a relatively new andhas yet to be adopted widely. 802.11a ismore expensive and as a result it notavailable for public access.

Wi -max


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Wi maxWi MAX is Worldwide Interoperability for Microwave Access.

The IEEE standard for Wi-MAX is 802.16 and falls under the category ofwireless Metropolitan Area Network (WMAN). Wi-MAX operates on twofrequency bands, 2 - 11GHz and 10 - 66GHz and has a range of about50km with speeds of up to 80Mbps.

This enables smaller wireless LANs to be interconnected by Wi-MAX creatinga large wireless MAN. Networking between cities can be achievedwithout the need for expensive cabling.

It is also able to provide high speed wireless broadband access to users. As itcan operate in two frequency bands Wi-MAX can work by line-of-sightand non-line-of-sight.

Wi-MAX, More Than Internet?


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Wi MAX, More Than Internet?

WiMAX has the potential toreplace a number of existingtelecommunicationsinfrastructures. In a fixedwireless configuration it canreplace the telephonecompany's copper wirenetworks, the cable TV's coaxialcable infrastructure whileoffering Internet ServiceProvider (ISP) services. In itsmobile variant, WiMAX has thepotential to replace cellular

networks.

Bluetooth Technology


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Bluetooth Technology

Bluetooth is an industrialspecification for wirelesspersonal area networks (PANs),also known as IEEE 802.15.1.Bluetooth provides a way toconnect and exchangeinformation between devicessuch as personal digitalassistants (PDAs), mobilephones, laptops, PCs, printers,digital cameras and video gameconsoles via a secure, globallyunlicensed short-range radio

frequency.

Bluetooth Contd.
http://en.wikipedia.org/wiki/Image:Bluetooth-logo.svg


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Bluetooth is a radio standard and communications protocol primarilydesigned for low power consumption, with a short range (power classdependent: 1 meter, 10 meters, 100 meters) based around low-costtransceiver microchips in each device.

Bluetooth lets these devices communicate with each other when theyare in range. The devices use a radio communications system, so theydo not have to be in line of sight of each other, and can even be inother rooms, so long as the received transmission is powerful enough.

Introduction


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Wi-MAXstands for Worldwide

Interoperability for Microwave Access IEEE 802.16standards-based wireless

Metropolitan Area Networktechnology

Extends upto 50 km (31 miles)& connectsIEEE 802.11( Wi-Fi Hotspots) to the internet

and provides a wireless extension to Cable

and DSL (Digital Subscriber Line) broadbandconnections over long distances.

IEEE 802.16, specifies WiMAX in the 10 to 66


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GHz range.

WiMAX technology also provides data ratesupto 70 mbps.

Wi Fi


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Wi-Fi is an acronym for Wireless Fidelity

IEEE 802.11standard for wireless local areanetworks (WLAN)

Wi-Fi was intended to be used for mobile

devices and LANs, but is now often used forInternetaccess.

Other wi fi standards are 802.11a, 802.11b

and 802.11g

Wi Fi: How it works
http://en.wikipedia.org/wiki/IEEE_802.11http://en.wikipedia.org/wiki/IEEE_802.11


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Setup requires Wi Fi hotspotscomposed of

many access points(AP). AP broadcasts its SSID(service set identifier)

via packets called beacons every 100 ms at 1

mbps. Based on settings of SSID, the client decides

whether to connect to an AP.

Based on the signal strength, the firmware onthe client wi fi card decides to which AP it willconnect.

Wifi standard allows the connection criteria


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and roaming totally open to the client.

Feature called Zero Configurationavailable inWindows XP shows any N/W available to the

user & lets the user connect to it on the fly i.e.

it controls the roaming criteria. Wi Fi has the same properties as an Ethernet

N/W.

Software Access Point sharing one Internet

connection


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co ect o

Wi Fi vs. Cellular

Ob t l t Wi Fi i i i


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Obstacles to Wi Fi are missing roaming,

authentication features(SIM cards, RADIUS) &the limited range of Wi-Fi.

Wi-Fi is ideal for VoIPapplications in acorporate LAN.

Wi-Fi only phones have limited range upto300ft& setting up a covering N/W would be very

expensive.

Companies: Zyxell, UT Starcomm, Samsung,Hitachi, etc. are offering VoIP Wi-Fi Phones for

reasonable prices.

Wi Fi vs. Bluetooth


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Bluetooth is for wireless PAN whereas Wi Fi is

for wireless LAN. Bluetooth is a low power, short range(30 ft)

N/W specification for transmission speeds of

800 kbpswhereas Wi-Fi is a fairly high power,medium range(300 ft) N/Wspecification for

transmission speeds of upto 54 mbps.

Bluetooth devices are embedded with a small,i i di i / i d l


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inexpensive radio transmitter/receiver module

whereas Wifi products have an inbuilt wi fichip/adapter/wi fi cardwhich access the

AP/hotspot within its proximity (300 ft radius)

for a fee.

Commercial Wi Fi

Commercial Wi Fi services are available in


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Commercial Wi Fi services are available inplaces such as Internet cafes, coffee houses

and airports around the world.

WiSETechnologies provides commercialhotspots for airports, universities &

independent cafes in the U.S.

In sept.2003,Ozoneparis in France, starteddeploying ozoneparis N/W across the city with

the aim to construct a wireless metropolitan

network with full wi fi coverage of Paris.

Sify, an Indian Internet service provider, hast 120 i l i t i B l


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set up 120 wireless access points in Bangalore,

India in hotels, malls and govt. offices. FON, a Spanish start-up created in Nov.2005,

aims to become the largest N/W of hotspots

in the world by the end of 2006 with 30,000access pointsfinancially supported by

companies like Google & Skype.

Advantages of Wi Fi

Wi Fi uses unlicensed radio spectrum &


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Wi Fi uses unlicensed radio spectrum&

doesnt require regulatory approval for

individual deployers.

Reduces the costof N/W deployment andExpansion.

Wi Fi products support roaming.

Many access points & N/W interfaces supportvarious degrees of encryptionto protect traffic

from interception.

Wi-Fi is a global set of standards.

Disadvantages of Wi Fi

Wi Fi uses the unlicensed 2 4 GHz spectrum


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Wi Fi uses the unlicensed 2.4 GHz spectrum,

which is also used by other technologies likeBluetooth, microwave ovens, cordless phones.

Thus causes degradation in performance.

Power consumption is fairly highcompared tosome other standards.

Wi Fi N/Ws have limited range. A typical wi fihome router using 802.11b/802.11g might

have a range of 45 m(150 ft) indoors& 90

m(300ft) outdoors.

Technical Advantages of Wi-MAX over Wi Fi


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WiMAX uses the LLClayer(standardised by

IEEE 802.2) used by other LANs & WANs, it canbe both bridged & routed to them.

IEEE 802.16 defines a MAC layer that supports

multiple physical layer(PHY)specifications. In wi fi the MAC uses contention access

causing interruption which reduces theirthroughput whereas WiMAX has a scheduling

MAC which works in time slots by the basestation.

How Wi-MAX works

WiMAX system consists of two parts: WiMAX


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WiMAX system consists of two parts: WiMAX

tower, WiMAX receiver. WiMAX tower station can connect directly to

the Internet using a high-bandwidth, wired

connection. It can also connect to another

WiMAX tower using a line-of-sight, microwave

link. This is called Backhaul.

A single tower can cover up to 3,000 squaremiles. Thus WiMAX provides coverage to

remote rural areas.

WiMAX actually can provide two forms ofwireless service 1 non line of sight


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wireless service: 1.non-line-of-sight

service2. line-of-sight service

Through the stronger line-of-sight antennas,

the WiMAX transmitting station would senddata to WiMAX-enabled computers or routers

set up within the transmitter's 30-mile radius

(2,800 square miles or 9,300 square km of

coverage).This is what allows WiMAX to

achieve its maximum range.


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Uses of WiMAX

Provides up to 50 km (31 miles) of linear


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Provides up to 50 km (31 miles)of linear

service area range and allows connectivitybetween users without a direct line of sight.

Claims to provide shared data rates up to 70mbpswhich according to WiMAX proponents,

is enough bandwidth to simultaneously

support more than 60 businesseswith T1-type

connectivity and well over a thousand homes

at 1Mbit/s DSL-level connectivity.

WiMAX will allow interpenetration forbroadband service provision of VoIP video


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broadband service provision of VoIP, video,

and Internet accesssimultaneously.

Sonyand Microsoftare closely considering theaddition of WiMAX as a feature in their next

generation game console. This will allow

gamers to create ad hoc networks with other

players.

Conclusion WiMAX outdistances WiFi by miles WiFi's


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WiMAX outdistances WiFi by miles. WiFi s

range is about 100 feet (30 m). WiMAX willblanket a radius of 30 miles(50 km) with

wireless access. The increased range is due to

the frequencies used and the power of the

transmitter.

This outstanding efficiency along with speedof transmission (upto 70 mbps) makes WiMAX

a sort out technology in the field of wirelesst ki

computer basic knowledge

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