computer basic knowledge
TRANSCRIPT
-
7/24/2019 Computer Basic Knowledge
1/143
Computer BasicsPREPARED BYROHIT UPADHYAY
-
7/24/2019 Computer Basic Knowledge
2/143
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.
-
7/24/2019 Computer Basic Knowledge
3/143
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,)
-
7/24/2019 Computer Basic Knowledge
4/143
What does a Computer do?
Computers can perform four general
operations, which comprise the information
processing cycle.
Input
Process
Output
Storage
-
7/24/2019 Computer Basic Knowledge
5/143
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.
-
7/24/2019 Computer Basic Knowledge
6/143
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.
-
7/24/2019 Computer Basic Knowledge
7/143
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.
-
7/24/2019 Computer Basic Knowledge
8/143
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.
-
7/24/2019 Computer Basic Knowledge
9/143
Types of Computer Systems
-
7/24/2019 Computer Basic Knowledge
10/143
Microcomputer Systems
Personal Computer(PC)microcomputer foruse by an individual.
Professional Workstationa powerful,networked PC for business professionals.
Laptopsmall, portable PC.
-
7/24/2019 Computer Basic Knowledge
11/143
Microcomputer Systems
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.
-
7/24/2019 Computer Basic Knowledge
12/143
Microcomputer Systems
Network Computerslow-cost, sealedmicrocomputers with no or minimal disk
storage that are linked to the network.
Information Applianceshand-heldmicrocomputer devices.
-
7/24/2019 Computer Basic Knowledge
13/143
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.
-
7/24/2019 Computer Basic Knowledge
14/143
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.
-
7/24/2019 Computer Basic Knowledge
15/143
Computer Processing Speeds
Millisecondthousandth of a second
Microsecondmillionth of a second
Nanosecondbillionth of a second
Picosecondtrillionth of a second
-
7/24/2019 Computer Basic Knowledge
16/143
Computer Clock Speeds
MIPSmillion instructions per second
Megahertz(MHz)millions of cycles persecond
Gigahertz(GHz)billions of cycles per second
-
7/24/2019 Computer Basic Knowledge
17/143
Input Devices
Keyboard.
Mouse.
-
7/24/2019 Computer Basic Knowledge
18/143
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.
-
7/24/2019 Computer Basic Knowledge
19/143
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.
-
7/24/2019 Computer Basic Knowledge
20/143
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
-
7/24/2019 Computer Basic Knowledge
21/143
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.
-
7/24/2019 Computer Basic Knowledge
22/143
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.
-
7/24/2019 Computer Basic Knowledge
23/143
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.
-
7/24/2019 Computer Basic Knowledge
24/143
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.
-
7/24/2019 Computer Basic Knowledge
25/143
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.
-
7/24/2019 Computer Basic Knowledge
26/143
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.
-
7/24/2019 Computer Basic Knowledge
27/143
Peripherals Advice
-
7/24/2019 Computer Basic Knowledge
28/143
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
-
7/24/2019 Computer Basic Knowledge
29/143
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
-
7/24/2019 Computer Basic Knowledge
30/143
ASCII Codes
-
7/24/2019 Computer Basic Knowledge
31/143
What is Software?
Definition:
Various kinds of programs used to operatecomputers and related devices.
-
7/24/2019 Computer Basic Knowledge
32/143
Types of Software
-
7/24/2019 Computer Basic Knowledge
33/143
Types of Software
Application Software- performs informationprocessing tasks for end users.
System Softwaremanages and supportsoperations of computer systems and
networks.
-
7/24/2019 Computer Basic Knowledge
34/143
Application Software
General-Purposeprograms that performcommon information processing jobs for end
users.
Application-Specificsupport specificapplications of end users in business and
other fields.
-
7/24/2019 Computer Basic Knowledge
35/143
General-Purpose Application
Software
Software Suites Web Browsers Electronic Mail
Word Processing Spreadsheets Database Managers
Presentation Graphics Personal Information Managers Groupware
-
7/24/2019 Computer Basic Knowledge
36/143
Software Suites
-
7/24/2019 Computer Basic Knowledge
37/143
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.
-
7/24/2019 Computer Basic Knowledge
38/143
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
-
7/24/2019 Computer Basic Knowledge
39/143
The Pascaline: One of the Earliest Mechanical Calculators
-
7/24/2019 Computer Basic Knowledge
40/143
The Early Period: Up to 1940 (continued)
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
-
7/24/2019 Computer Basic Knowledge
41/143
The Early Period: Up to 1940 (continued)
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.
-
7/24/2019 Computer Basic Knowledge
42/143
Drawing of the Jacquard Loom
-
7/24/2019 Computer Basic Knowledge
43/143
The Early Period: Up to 1940 (continued)
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)
-
7/24/2019 Computer Basic Knowledge
44/143
The Early Period: Up to 1940 (continued)
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
-
7/24/2019 Computer Basic Knowledge
45/143
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
-
7/24/2019 Computer Basic Knowledge
46/143
Photograph of the ENIAC Computer
h i h f
-
7/24/2019 Computer Basic Knowledge
47/143
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
-
7/24/2019 Computer Basic Knowledge
48/143
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
-
7/24/2019 Computer Basic Knowledge
49/143
The Modern Era: 1950 to the Present
(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
-
7/24/2019 Computer Basic Knowledge
50/143
The Modern Era: 1950 to the Present
(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
-
7/24/2019 Computer Basic Knowledge
51/143
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
-
7/24/2019 Computer Basic Knowledge
52/143
The Altair 8800, the Worlds First Microcomputer
Th M d E 1950 t th P t
-
7/24/2019 Computer Basic Knowledge
53/143
The Modern Era: 1950 to the Present
(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
Th M d E 1950 t th P t
-
7/24/2019 Computer Basic Knowledge
54/143
The Modern Era: 1950 to the Present
(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
-
7/24/2019 Computer Basic Knowledge
55/143
Computer Software
Computer software is the key toproductive use of computers. Software
can be categorized into two types:
Operating system software
Application software.
-
7/24/2019 Computer Basic Knowledge
56/143
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.
-
7/24/2019 Computer Basic Knowledge
57/143
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
-
7/24/2019 Computer Basic Knowledge
58/143
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
-
7/24/2019 Computer Basic Knowledge
59/143
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
-
7/24/2019 Computer Basic Knowledge
60/143
INTRODUCTION TO COMPUTERNETWORKS
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
61/143
Computer Networks
Computer network connectstwo or more autonomouscomputers.
The computers can begeographically locatedanywhere.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
62/143
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)
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
63/143
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
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
64/143
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.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
65/143
Bus Topology
Commonly referred to as alinear bus, all the devices ona bus topology are connected
by one single cable.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
66/143
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.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
67/143
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.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
68/143
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.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
69/143
Network Components
Physical Media
Interconnecting Devices
Computers
Networking Software
Applications
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
70/143
Networking Media
Networking media can bedefined simply as the meansby which signals (data) aresent from one computer to
another (either by cable orwireless means).
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
71/143
Networking Devices
HUB, Switches, Routers, WirelessAccess Points, Modems etc.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
72/143
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.
Introduction to Computer Networks
-
7/24/2019 Computer Basic Knowledge
73/143
Applications
E-mail
Searchable Data (Web Sites)
E-Commerce
News Groups
Internet Telephony (VoIP)Video Conferencing
Chat Groups
Instant Messengers
Internet Radio
LAN Technologies
-
7/24/2019 Computer Basic Knowledge
74/143
Ethernet BUS Topology
Repeater
LAN Technologies
-
7/24/2019 Computer Basic Knowledge
75/143
Ethernet STAR Topology
Hub
-
7/24/2019 Computer Basic Knowledge
76/143
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
-
7/24/2019 Computer Basic Knowledge
77/143
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
-
7/24/2019 Computer Basic Knowledge
78/143
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
-
7/24/2019 Computer Basic Knowledge
79/143
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
-
7/24/2019 Computer Basic Knowledge
80/143
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
-
7/24/2019 Computer Basic Knowledge
81/143
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
-
7/24/2019 Computer Basic Knowledge
82/143
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
-
7/24/2019 Computer Basic Knowledge
83/143
Layered System View
Clients, partners, customers
Intranet
Extranet
Internet
Corporate members
Global society competitors
Internets and Extranets
-
7/24/2019 Computer Basic Knowledge
84/143
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
-
7/24/2019 Computer Basic Knowledge
85/143
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
-
7/24/2019 Computer Basic Knowledge
86/143
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
-
7/24/2019 Computer Basic Knowledge
87/143
Have a
nice day
Encryption
software
running onsending
computer
Decryption
software
running on
Receiving
computer
E%$&:}{|
Have a
nice day
What is the Internet
-
7/24/2019 Computer Basic Knowledge
88/143
What is the Internet
The Internet connects millions of servers.
I t t d E t t
-
7/24/2019 Computer Basic Knowledge
89/143
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
-
7/24/2019 Computer Basic Knowledge
90/143
Intranets and Extranets
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
Intranets and Extranets
-
7/24/2019 Computer Basic Knowledge
91/143
Internet, intranet, and extranet potential for productivity enhancement
The Internet
-
7/24/2019 Computer Basic Knowledge
92/143
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
-
7/24/2019 Computer Basic Knowledge
93/143
How the Internet Works
-
7/24/2019 Computer Basic Knowledge
94/143
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
-
7/24/2019 Computer Basic Knowledge
95/143
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
-
7/24/2019 Computer Basic Knowledge
96/143
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
-
7/24/2019 Computer Basic Knowledge
97/143
Three Ways to Access the
Internet
Schematic
-
7/24/2019 Computer Basic Knowledge
98/143
Internet Service Providers
-
7/24/2019 Computer Basic Knowledge
99/143
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
-
7/24/2019 Computer Basic Knowledge
100/143
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
-
7/24/2019 Computer Basic Knowledge
101/143
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
Intranets and Extranets
-
7/24/2019 Computer Basic Knowledge
102/143
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 linksselected resources of the intranet of a company
with its customers, suppliers, or other business
partners
Intranet
-
7/24/2019 Computer Basic Knowledge
103/143
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
-
7/24/2019 Computer Basic Knowledge
104/143
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
-
7/24/2019 Computer Basic Knowledge
105/143
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.
-
7/24/2019 Computer Basic Knowledge
106/143
"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
-
7/24/2019 Computer Basic Knowledge
107/143
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.
-
7/24/2019 Computer Basic Knowledge
108/143
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
-
7/24/2019 Computer Basic Knowledge
109/143
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
-
7/24/2019 Computer Basic Knowledge
110/143
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
-
7/24/2019 Computer Basic Knowledge
111/143
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.
-
7/24/2019 Computer Basic Knowledge
112/143
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
-
7/24/2019 Computer Basic Knowledge
113/143
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
-
7/24/2019 Computer Basic Knowledge
114/143
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.
-
7/24/2019 Computer Basic Knowledge
115/143
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.
-
7/24/2019 Computer Basic Knowledge
116/143
As cables are not required, it would
be less cumbersome carrying apersonal blue tooth device and
space would be less cluttered.
-
7/24/2019 Computer Basic Knowledge
117/143
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
-
7/24/2019 Computer Basic Knowledge
118/143
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 -
7/24/2019 Computer Basic Knowledge
119/143
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
-
7/24/2019 Computer Basic Knowledge
120/143
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?
-
7/24/2019 Computer Basic Knowledge
121/143
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
-
7/24/2019 Computer Basic Knowledge
122/143
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 -
7/24/2019 Computer Basic Knowledge
123/143
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
-
7/24/2019 Computer Basic Knowledge
124/143
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
-
7/24/2019 Computer Basic Knowledge
125/143
GHz range.
WiMAX technology also provides data ratesupto 70 mbps.
Wi Fi
-
7/24/2019 Computer Basic Knowledge
126/143
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 -
7/24/2019 Computer Basic Knowledge
127/143
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
-
7/24/2019 Computer Basic Knowledge
128/143
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
-
7/24/2019 Computer Basic Knowledge
129/143
co ect o
Wi Fi vs. Cellular
Ob t l t Wi Fi i i i
-
7/24/2019 Computer Basic Knowledge
130/143
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
-
7/24/2019 Computer Basic Knowledge
131/143
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
-
7/24/2019 Computer Basic Knowledge
132/143
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
-
7/24/2019 Computer Basic Knowledge
133/143
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
-
7/24/2019 Computer Basic Knowledge
134/143
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 &
-
7/24/2019 Computer Basic Knowledge
135/143
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
-
7/24/2019 Computer Basic Knowledge
136/143
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
-
7/24/2019 Computer Basic Knowledge
137/143
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
-
7/24/2019 Computer Basic Knowledge
138/143
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
-
7/24/2019 Computer Basic Knowledge
139/143
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.
-
7/24/2019 Computer Basic Knowledge
140/143
Uses of WiMAX
Provides up to 50 km (31 miles) of linear
-
7/24/2019 Computer Basic Knowledge
141/143
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
-
7/24/2019 Computer Basic Knowledge
142/143
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
-
7/24/2019 Computer Basic Knowledge
143/143
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