Mod Three Computer Basics

Mod Three Computer Basics

What Is A aComputer? 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), and produce information (output) from the processing. Generally, the term is used to describe a collection of devices that function together as a system.

Devices that comprise a computer system

Monitor (output )

Speake r (output )

Printer (output )

System unit (processor, memory…)

Storage devices (CD-RW, Floppy, Hard disk, zip,…) Scanne r (input)

Mouse (input) Keyboard (input)

What Does A Computer Do? can perform four general operations, Computers which comprise the information processing cycle. Input  Process  Output  Storage 

Data and Information 

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All computer processing requires data, which is a collection of raw facts, figures and symbols, such as numbers, 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, and useful. During the output Phase, the information that has been created is put into some form, such as a printed report. The information can also be put in computer storage for future use.

Why Is A Computer So Powerful? 

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The ability to perform the information processing cycle with amazing speed. Reliability (low failure rate). Accuracy. Ability to store huge amounts of data and information. Ability to communicate with other computers.

How Does a Computer Know what to do? 

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It must be given a detailed list of instructions, called a compute program or software, that tells it exactly what to do. Before processing a specific job, the computer program 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.

What Are The Primary Components Of A Computer ?  

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Input devices. Central Processing Unit (containing the control unit and the arithmetic/logic unit). Memory. Output devices. Storage devices.

Types of Computer Systems

Microcomputer Systems 

Personal Computer (PC) – microcomputer for use by an individual

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Professional Workstation – a powerful, networked PC for business professionals

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Laptop – small, portable PC

Microcomputer Systems 

Network Server – more powerful microcomputers that coordinate telecommunications and resource sharing in small local area networks and Internet and intranet websites

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Computer Terminals – depend on servers for software, storage and processing power

Microcomputer Systems 

Network Computers – low-cost, sealed microcomputers with no or minimal disk storage that are linked to the network

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Information Appliances – hand-held microcomputer devices

Hardware Organized by System Functions 

Input Devices convert data into electronic form for direct entry or through a telecommunications network into a computer system

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Processing Components primarily the Central Processing Unit (CPU) 

Arithmetic-Logic Unit (ALU) - perform arithmetic and logic functions required to execute software instructions

Hardware Organized by System Functions 

Output Devices convert electronic information produced by the computer system into human-intelligible form for presentation to end users

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Storage Devices store data and software instructions needed for processing

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Control Components primarily the CPU’s Control Unit which interprets software instructions and transmits directions that control the activities of the other components of the computer system

Computer Processing Speeds 

Millisecond – thousandth of a second

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Microsecond – millionth of a second

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Nanosecond – billionth of a second

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Picosecond – trillionth of a second

Computer Clock Speeds 

MIPS – million instructions per second

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Megahertz (MHz) – millions of cycles per second

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Gigahertz (GHz) – billions of cycles per second

Input Devices Keyboard.  Mouse. 

The Keyboard The 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.

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 detects movement of the mouse.

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 “brain” of the computer. Control Unit- ALU

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 ROM is memory that is etched on a chip that has start-up directions for your computer. It is permanent memory.

Amount of RAM In The amount of memory in computers is typically Computers measured in kilobytes or megabytes. One kilobyte (K or KB) equals approximately 1,000 memory locations and one megabyte (M or MB) equals approximately one million locations A memory location, or byte, usually stores one character. Therefore, a computer with 8 MB of memory can store approximately 8 million characters. One megabyte can hold approximately 500 pages of text information.

Output Devices Output devices make the information resulting from the processing available for use. The two output devices more commonly used are the printer and the computer screen. The printer produces a hard copy of your output, and the computer screen produces a soft copy of your output.

Storage Devices Auxiliary storage devices are used to store data when they are not being used in memory. The most common types of auxiliary storage used on personal computers are floppy disks, hard disks and CD-ROM drives.

Floppy Disks A floppy inexpensive consists of plastic disk enclosed in shell.

disk is a portable, storage medium that a thin, circular, flexible with a magnetic coating a square-shaped plastic

Compact Discs 

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A compact disk (CD), also called an optical disc, is a flat round, portable storage medium that is usually 4.75 inch in diameter. A CD-ROM (read only memory), is a compact disc that 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.

Peripherals Advice

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

RAM vs. ROM 

Random Access Memory (RAM) – each memory position can be both sensed and changed

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Read Only Memory (ROM) – can be read but not erased or overwritten

ASCII Codes

What is Software? Definition:  Various kinds of programs used to operate computers and related devices

Types of Software

Types of Software 

Application Software - performs information processing tasks for end users

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System Software – manages and supports operations of computer systems and networks

Application Software 

General-Purpose – programs that perform common information processing jobs for end users

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Application-Specific – support specific applications of end users in business and other fields

General-Purpose Application Software         

Software Suites Web Browsers Electronic Mail Word Processing Spreadsheets Database Managers Presentation Graphics Personal Information Managers Groupware

Software Suites

The Early Period: Up to 1940 

3,000 years ago: Mathematics, logic, and numerical computation 

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1614: Logarithms 

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Important contributions made by the Greeks, Egyptians, Babylonians, Indians, Chinese, and Persians Invented by John Napier to simplify difficult mathematical computations

Around 1622: First slide rule created

The Early Period: Up to 1940 (continued) 

1672: The Pascaline   

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Designed and built by Blaise Pascal One of the first mechanical calculators Could do addition and subtraction

1674: Leibnitz’s Wheel   

Constructed by Gottfried Leibnitz Mechanical calculator Could do addition, subtraction, multiplication, and division

The Pascaline: One of the Earliest Mechanical Calculators

The Early Period: Up to 1940 (continued) 

1801: The Jacquard loom   

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Developed by Joseph Jacquard Automated loom Used punched cards to create desired pattern

1823: The Difference Engine 

Developed by Charles Babbage

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Did addition, subtraction, multiplication, and division to 6 significant digits Solved polynomial equations and other complex mathematical problems

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The Early Period: Up to 1940 (continued) 

1823: The Difference Engine 

Developed by Charles Babbage

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Capabilities: 

Addition, subtraction, multiplication, and division to 6 significant digits

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Solve polynomial equations and other complex mathematical problems

Drawing of the Jacquard Loom

The Early Period: Up to 1940 (continued) 

1830s: The Analytic Engine  

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Designed by Charles Babbage More powerful and general-purpose computational machine Components were functionally similar to the four major components of today’s computers    

Mill (modern terminology: arithmetic/logic unit) Store (modern terminology: memory) Operator (modern terminology: processor) Output (modern terminology: input/output)

The Early Period: Up to 1940 (continued) 

1890: U.S. census carried out with programmable card processing machines 

Built by Herman Hollerith

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

The Birth of Computers: 1940–1950 

Development of electronic, general-purpose computers  

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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

Photograph of the ENIAC Computer

The Birth of Computers: 1940–1950 

Stored program computer model  

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Proposed by John Von Neumann in 1946 Stored binary algorithm in the computer’s 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

The Modern Era: 1950 to the Present 

First generation of computing (1950-1959) 

Used vacuum tubes to store data and programs

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Each computer was multiple rooms in size

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Computers were not very reliable

The Modern Era: 1950 to the Present (continued) 

Second generation of computing (1959-1965) 

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Replaced vacuum tubes by transistors and magnetic cores Dramatic reduction in size 

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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

The Modern Era: 1950 to the Present (continued) 

Third generation of computing (1965-1975) 

Used integrated circuits rather than individual electronic components

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Further reduction in size and cost of computers

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Computers became desk-sized

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First minicomputer developed

Software industry formed

The Modern Era: 1950 to the Present (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

The Altair 8800, the World’s First Microcomputer

The Modern Era: 1950 to the Present (continued) 

Fifth generation of computing (1985-?) 

Recent developments 

Massively parallel processors

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Handheld devices and other types of personal digital assistants (PDAs)

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High-resolution graphics

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

The Modern Era: 1950 to the Present (continued) 

Recent developments (continued) 

Integrated global telecommunications incorporating data, television, telephone, FAX, the Internet, and the World Wide Web

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Wireless data communications

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Massive storage devices

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Ubiquitous computing

Some of the Major Advancements in Computing

Some of the Major Advancements in Computing

Computer Software Computer software is the key to productive use of computers. Software can be categorized into two types: Operating system software  Application software. 

Operating System Operating system software tells the computer how to Software perform the functions of loading, storing and executing an application and how to transfer data. Today, many computers use an operating system that has a graphical user interface (GUI) that provides visual clues such as icon symbols to help the user. Microsoft Windows 98 is a widely used graphical operating system. DOS (Disk Operating System) is an older but still widely used operating system that is text-based.

Application Software Application Software consists of programs that tell a computer how to produce information. Some of the more commonly used packages are: Word processing  Electronic spreadsheet  Database  Presentation graphics 

Computers and software 

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Application software is designed to solve a specific problem System software provides a general programming environment   

Operating system is a subset of the system software Provide functions used by the application software Provides the mechanisms for application software to share the 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

System Software 

Runtime system for a programming language  C libraries runtime 

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Standard input/output (I/O) library – procedures to perform buffered input/output on a stream of data The math library – functions to perform various mathematical functions Graphics libraries – functions to render images on a bitmapped display

Window system – software that provides a virtual terminal to an application program

Introduction to Computer Networks

INTRODUCTION TO COMPUTER NETWORKS

Introduction to Computer Networks

Computer Networks Computer network connects two or more autonomous computers. The computers can be geographically located anywhere.

Introduction to Computer Networks

LAN, MAN & WAN Network in small geographical Area (Room, Building or a Campus) is called LAN (Local Area Network)

Network in a City is call MAN (Metropolitan Area Network)

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

Introduction to Computer Networks

Applications of Networks Resource Sharing Hardware (computing resources, disks, printers) Software (application software) Information Sharing Easy accessibility from anywhere (files, databases) Search Capability (WWW) Communication Email Message broadcast Remote computing

Introduction to Computer Networks

Network Topology The network topology defines the way in which computers, printers, and other devices are connected. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions.

Introduction to Computer Networks

Bus Topology Commonly referred to as a linear bus, all the devices on a bus topology are connected by one single cable.

Introduction to Computer Networks

Star & Tree Topology The star topology is the most commonly used architecture in Ethernet LANs. When installed, the star topology resembles spokes in a bicycle wheel. Larger networks use the extended star topology also called tree topology. When used with network devices that filter frames or packets, like bridges, switches, and routers, this topology significantly reduces the traffic on the wires by sending packets only to the wires of the destination host.

Introduction to Computer Networks

Ring Topology A frame travels around the ring, stopping at each node. If a node wants to transmit data, it adds the data as well as the destination address to the frame. The frame then continues around the ring until it finds the destination node, which takes the data out of the frame.

Single ring – All the devices on the network share a single cable Dual ring – The dual ring topology allows data to be sent in both directions.

Introduction to Computer Networks

Mesh Topology The mesh topology connects all devices (nodes) to each other for redundancy and fault tolerance. It is used in WANs to interconnect LANs and for mission critical networks like those used by banks and financial institutions. Implementing topology is difficult.

the mesh expensive and

Introduction to Computer Networks

Network Components Physical Media Interconnecting Devices Computers Networking Software Applications

Introduction to Computer Networks

Networking Media Networking media can be defined simply as the means by which signals (data) are sent from one computer to another (either by cable or wireless means).

Introduction to Computer Networks

Networking Devices HUB, Switches, Wireless Access Modems etc.

Routers, Points,

Introduction to Computer Networks

Computers: Clients and Servers In a client/server network arrangement, network services are located in a dedicated computer whose only function is to respond to the requests of clients.

The server contains the file, print, application, security, and other services in a central computer that is continuously available to respond to client requests.

Introduction to Computer Networks

Applications E-mail Searchable Data (Web Sites) E-Commerce News Groups Internet Telephony (VoIP) Video Conferencing Chat Groups Instant Messengers Internet Radio

LAN Technologies

Ethernet BUS Topology

Repeater

LAN Technologies

Ethernet STAR Topology

Hub

Classification of computers

Classification of computers according to purpose General purpose computers A general purpose computers is designed to perform all the needs of the society. These computers have the ability to store numerous programs. These computers can be used for various applications, ranging for various applications, ranging from scientific as well as business purpose.

Classification of computers according to purpose Specific purpose computers These computers are designed to handle problem or to perform a single specific task. A set of programs are built into the machine and hence cannot perform other types of task. The computers used for airline reservations', satellite tracking, and air traffic control are specific purpose computers.

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 do not deal directly with numbers. Analog computers are used for scientific and engineering purposes.

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.

Hybrid computers 

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The hybrid computers combines analog and digital capabilities. 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 special devices. A converter is used to convert analog data into digital data and vice-versa.e.g., ROBOT is the best example of hybrid computer. These computers are used for scientific applications, various field of engineering and in industrial control process.

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

Layered System View

Intranet

Corporate members

Extranet

Clients, partners, customers

Internet

Global society: competitors

Internets and Extranets 

Intranets  

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Extranets  

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Private network within an organization Provides information to employees Private network that connects organizations Used to allow suppliers and others access

Firewalls  

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Security system Protects against external threats

Internet Introduction 

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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 technologies for information gathering and distribution within an organization. Extranet: An extranet is a community of interest created by extending an intranet to selected entities external to an organization.

The Internet 

The internet  

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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

Have a nice day…

Encryption software running on sending computer E%$&:”}{|…

Decryption software running on Receiving computer

Have a nice day…

What is the Internet

The Internet connects millions of servers.

Intranets and Extranets 

Intranet 

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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 its customers, suppliers, or other business partners

Intranets and Extranets 

Intranet 

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A within-organization computer network that uses Internet technologies to communicate

Extranet 

Uses Internet technologies to facilitate communication and trade between an organization and its business partners, such as suppliers

Intranets and Extranets

Internet, intranet, and extranet potential for productivity enhancement

The Internet 

The internet  

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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

How the Internet Works 

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Transport control protocol (TCP)  A protocol that operates at the transport layer and is used in combination with IP by most Internet applications Backbone  An Internet high-speed, long distance communications links (like a bus; wire that connects nodes) Uniform resource locator (URL)  An assigned address on the Internet for each computer  E.g., http://www.yorku.ca/

Domain Affiliations Domain arts com edu firm gov info mil nom net org rec store web net

Affiliations cultural and entertainment activities business organizations educational sites businesses and firms government sites information service providers military sites individuals networking organizations organizations recreational activities businesses offering goods for purchase entities related to World Wide Web activities networking organizations

Access to the Internet 

LAN servers 

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Serial line internet protocol (SLIP) and Point-to-point protocol (PPP) 

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Local servers can provide access to the Internet through normal connections (e.g., Ethernet)

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. These services usually require sign-up procedures

Three Ways to Access the Internet

Schematic

Internet Service Providers 

Internet service provider (ISP) 

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Any company that provides individuals or companies with access to the Internet Thousands of providers including large communications companies Need an account with the ISP and software that links with TCP/IP

The World Wide Web 

World Wide Web 

A collection of tens of thousands of independentlyowned computers that work together as one in an Internet service

WWW Terminology 

Home page 

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Hypermedia 

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The cover page for a Web site that has graphics, titles, coloured text, etc. 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

Intranets and Extranets 

Intranet 

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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 its customers, suppliers, or other business partners

Intranet A network based on TCP/IP protocols (an internet) belonging to an organization, usually a corporation, accessible only by the organization's members, employees, or others with authorization. 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 A new buzzword that refers to an intranet that is partially accessible to authorized outsiders. Whereas an intranet resides behind a firewall and is accessible only to people who are members of the same company or organization, an extranet provides various levels of accessibility to outsiders. You can access an extranet only if you have a valid username and password, and your identity determines which parts of the extranet you can view. Extranets are becoming a very popular means for business partners to exchange information.

Firewall 

Firewall… 

A device that sits between your internal network and the outside Internet and limits access into and out of your network based on your organization’s access policy

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 data between devices.  Wireless refers to communication without cables or 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 together with wires).

Internet  The

internet is a worldwide interconnection of many different computers and networks.  The internet allows users to efficiently share information, programs and equipments and to communicate with each other.

The internet was originally developed by the department of defense and the national 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 internet community. 

Advantages of extranet     

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Exchange large volumes of data using Electronic Data Interchange (EDI) Share product catalogs exclusively with wholesalers or those "in the trade" Collaborate with other companies on joint development efforts Jointly develop and use training programs with other companies Provide or access services provided by one company to a group of other companies, such as an online banking application managed by one company on behalf of affiliated banks Share news of common interest exclusively

Disadvantages of extranet 

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Extranets can be expensive to implement and maintain within an organization (e.g.: hardware, software, employee training costs) Security of extranets can be a big concern when dealing with valuable information. System access needs to be carefully controlled to avoid sensitive information falling into the wrong hands. 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, which hurts the business when it comes to loyalty of its business partners and customers.

Wireless technologies 

Bluetooth, WiFi and WiMAX are wireless technologies which allow devices to interconnect and communicate with each other. Radio waves are electro magnetic waves and have different frequencies. These technologies are radio frequencies. Similar to the analogue radio, or FM radio.

Bluetooth works on 2.45GHz frequency.  WiFi works in two frequency bands 2.4GHz and 5GHz.  WiMAX- Wi MAX is Worldwide Interoperability for Microwave Access works in two frequency bands, 2 - 11GHz and 10 - 66GHz. 

Blue tooth 

Named after the Danish king, Harold Blue tooth, was the first to emerge, several devices like mobile phones, pdas, headsets, keyboards, mice, medical equipment and even cars now come with this feature.

Due to its low cost, manufacturers are willing to implement this technology in most devices. It is designed for short range communications with a range of about 10m. As a result, it consumes less power and are suited for very small battery powered devices and portable devices.

Problems associated when devices communicate via infrared or cables are removed. Infrared requires a line of sight, blue tooth only needs to be in reasonable vicinity.

As cables are not required, it would be less cumbersome carrying a personal blue tooth device and space would be less cluttered.

As blue tooth devices automatically communicate with each other, it requires very little from the user. Bluetooth allows for a wireless Personal Area Network (PAN) with it's short range.

Wi - fi WiFi or Wireless Fidelity, has a range of about 100m and allows for faster data transfer rate between 10 - 54Mbps. There are three different wireless standards under WiFi, 802.11a, 802.11b and 802.11g. 802.11 being the wireless standard set by The Institue of Electrical and Electronic Engineers (IEEE). WiFi is used to create wireless Local Area Networks (WLAN).

The most widely used standard is 802.11b and 802.11g is expexcted to grow rapidly. These two standards are relatively inexpensive and can be found providing wireless connectivity in airports, railway stations, cafes, bars, restaurants and other public areas. The main difference between the two is the speed. 802.11b has data transfer rate of upto 11Mbps and 802.11g has a rate of upto 54Mbps. 802.11g is a relatively new and has yet to be adopted widely. 802.11a is more expensive and as a result it not available for public access.

Wi -max Wi MAX is Worldwide Interoperability for Microwave Access. The IEEE standard for WiMAX is 802.16 and falls under the category of wireless Metropolitan Area Network (WMAN). WiMAX operates on two frequency bands, 2 - 11GHz and 10 66GHz and has a range of about 50km with speeds of up to 80Mbps. This enables smaller wireless LANs to be interconnected by WiMAX creating a large wireless MAN. Networking between cities can be achieved without the need for expensive cabling. It is also able to provide high speed wireless broadband access to users. As it can operate in two frequency bands WiMAX can work by line-of-sight and non-line-of-sight.

WiMAX, More Than Internet? 

WiMAX has the potential to replace a number of existing telecommunications infrastructures. In a fixed wireless configuration it can replace the telephone company's copper wire networks, the cable TV's coaxial cable infrastructure while offering Internet Service Provider (ISP) services. In its mobile variant, WiMAX has the potential to replace cellular networks.

Bluetooth Technology 

Bluetooth is an industrial specification for wireless personal area networks (PANs), also known as IEEE 802.15.1. Bluetooth provides a way to connect and exchange information between devices such as personal digital assistants (PDAs), mobile phones, laptops, PCs, printers, digital cameras and video game consoles via a secure, globally unlicensed shortrange radio frequency.

Bluetooth Contd. 

Bluetooth is a radio standard and communications protocol primarily designed for low power consumption, with a short range (power class dependent: 1 meter, 10 meters, 100 meters) based around low-cost transceiver microchips in each device.

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

How it all started 

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The Bluetooth specification was first developed in 1994 by Jaap Haartsen, who was working for Ericsson Radio Systems located in Emmen in The Netherlands. The specifications were formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on May 20, 1998. Today it has over 1800 companies worldwide. It was established by Ericsson, Sony Ericsson, IBM, Intel, Toshiba and Nokia, and later joined by many other companies as Associate or Adopter members. Bluetooth is also known as IEEE 802.15.1. http://en.wikipedia.org/wiki/Bluetooth

Introduction 

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WiMAX stands for Worldwide Interoperability for Microwave Access IEEE 802.16 standards-based wireless Metropolitan Area Network technology Extends upto 50 km (31 miles) & connects IEEE 802.11( Wi-Fi Hotspots) to the internet and provides a wireless extension to Cable and DSL (Digital Subscriber Line) broadband connections over long distances.

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IEEE 802.16, specifies WiMAX in the 10 to 66 GHz range. WiMAX technology also provides data rates upto 70 mbps.

Wi Fi  

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Wi-Fi is an acronym for Wireless Fidelity IEEE 802.11 standard for wireless local area networks (WLAN) Wi-Fi was intended to be used for mobile devices and LANs, but is now often used for Internet access. Other wi fi standards are 802.11a, 802.11b and 802.11g

Wi Fi: How it works 

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Setup requires Wi Fi hotspots composed 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 on the client wi fi card decides to which AP it will connect.

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Wifi standard allows the connection criteria and roaming totally open to the client. Feature called Zero Configuration available in Windows 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

Photo Courtesy – Data communication and Networking by “Behrouz A.Forouzan.”

Wi Fi vs. Cellular 

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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 VoIP applications in a corporate LAN. Wi-Fi only phones have limited range upto 300 ft & 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 kbps whereas Wi-Fi is a fairly high power, medium range(300 ft) N/W specification for transmission speeds of upto 54 mbps.

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Bluetooth devices are embedded with a small, inexpensive radio transmitter/receiver module whereas Wifi products have an inbuilt wi fi chip/adapter/wi fi card which access the AP/hotspot within its proximity (300 ft radius) for a fee.

Commercial Wi Fi 

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Commercial Wi Fi services are available in places such as Internet cafes, coffee houses and airports around the world. WiSE Technologies provides commercial hotspots for airports, universities & independent cafes in the U.S. In sept.2003,Ozoneparis in France, started deploying ozoneparis N/W across the city with the aim to construct a wireless metropolitan network with full wi fi coverage of Paris.

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Sify, an Indian Internet service provider, has 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 30,000 access points financially supported by companies like Google & Skype.

Advantages of Wi Fi 

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Wi Fi uses unlicensed radio spectrum & doesn’t require regulatory approval for individual deployers. Reduces the cost of N/W deployment and Expansion. Wi Fi products support roaming. Many access points & N/W interfaces support various degrees of encryption to protect traffic from interception. Wi-Fi is a global set of standards.

Disadvantages of Wi Fi 

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Wi Fi uses the unlicensed 2.4 GHz spectrum, which is also used by other technologies like Bluetooth, microwave ovens, cordless phones. Thus causes degradation in performance. Power consumption is fairly high compared to some other standards. Wi Fi N/Ws have limited range. A typical wi fi home router using 802.11b/802.11g might have a range of 45 m(150 ft) indoors & 90 m(300ft) outdoors.

Technical Advantages of WiMAX over Wi Fi 

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WiMAX uses the LLC layer(standardised by IEEE 802.2) used by other LANs & WANs, it can be 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 their throughput whereas WiMAX has a scheduling MAC which works in time slots by the base station.

How WiMAX works 

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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 square miles. Thus WiMAX provides coverage to remote rural areas.

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WiMAX actually can provide two forms of wireless service: 1. non-line-of-sight service 2. line-of-sight service Through the stronger line-of-sight antennas, the WiMAX transmitting station would send data 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.

Uses of WiMAX 

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Provides up to 50 km (31 miles) of linear service area range and allows connectivity between users without a direct line of sight. Claims to provide shared data rates up to 70 mbps which according to WiMAX proponents, is enough bandwidth to simultaneously support more than 60 businesses with T1type connectivity and well over a thousand homes at 1Mbit/s DSL-level connectivity.

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WiMAX will allow interpenetration for broadband service provision of VoIP, video, and Internet access—simultaneously. Sony and Microsoft are closely considering the addition of WiMAX as a feature in their next generation game console. This will allow gamers to create ad hoc networks with other players.

Conclusion 

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WiMAX outdistances WiFi by miles. WiFi's range is about 100 feet (30 m). WiMAX will blanket 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 speed of transmission (upto 70 mbps) makes WiMAX a sort out technology in the field of wireless networking.