Transcript intro.doc - Reocities

The Least You Need to Know, A Lot to Learn
• The Internet is a huge computer network -the world’s
largest- and it’s open to the public.
• E-mail may not be glamorous, but it’s the most
important tool on the Internet.
• The World Wide Web is not the Internet.
• A new system’s appearing on the Internet, push.
• There are tens of thousands of discussion groups on the
Internet- newsgroup, mailing lists, and Web forums.
The Least You Need to Know(Cont’.)
• Three services- Gopher, FTP, and Telnet- have become
submerged in all the fuss about the World Wide Web.
• The Internet is a communication system either with
your voice or without your voice.
• The Internet is constantly changing. It’s the nature of
the Internet. That’s why you have to learn how to
search for thins on the Internet.
The Least You Need to Know(Cont’.)
• We’ve heard about the dangers of the Internet, so we
have to know what it takes to stay safe.
• The Internet is a hardware system, so you’ll need
software. We’ll learn where to find all kinds of
software.
• There are thousands of reasons to use the Internet. We
have to study its applications.
What is the Internet?
• What’s a computer network? It’s a system in which
computers are connected so they can share
“information”.
– Information is anything you can send over lines of
electronic communication - e-mail, word processing
files, documents, programs, sounds, music, and
anything else that can be electronically encoded.
– There are millions of networks around the world.
What is the Internet?(Cont’)
• What’s the Internet?
– The world’s largest computer network.
– It’s open to anyone with the entrance fee, and the
entrance fee is constantly dropping.
• There are a whole lot of people out there; the numbers
are definitely in the tens of millions.
The History of the Internet
• Late 1960s, ARPANET was originally designed by the
U.S. Department of Defense, Advanced Research
Projects Agency(DARPA) to share information and
survive a nuclear attack.
• In1989,those networks created for military use were
dismantled and replaced by the National Science
Foundation, NSFNET
The Internet Services
• E-mail
– The electronic world’s postal system is very much like
the real world’s postal system, except that you can’t
send fruit or bombs.
• Discussion groups
– Newsgroups
– Mailing lists
– Web Forums
The Internet Services (Cont’)
• Chat
– You type a message, and it’s instantly transmitted to
another person, or to many other people, who can type
his response right away.
• Internet Phones
– Install a sound card and microphone, get the Internet
Phone software, and then talk to people across the
Internet.
The Internet Services (Cont’)
• FTP, the grand old man of the Internet
– The whole purpose of the Internet was to transfer files
from one place to another. FTP provides a giant
electronic “library” of computer files.
• Archie
– Archie is like the library’s card catalog, telling you
which file is kept where.
The Internet Services (Cont’)
• Gopher, the poor old too
– Converts a command-line computer system to a menu
system.
• Telnet
– Provides a way to log onto a computer that’s
connected somewhere out there on the Internet.
The Internet Services (Cont’)
• World Wide Web
– Containing pictures, sounds, and animation the Web is
a giant”hypertext” system in which documents around
the world are linked to one another.
• Push Programs
– A “scheduled pull” system.
– Periodically information is sent to your computer
without your direct intervention.
Internet Terminology
• Service Provider
– ISP (Internet Service Provider)
– The company generally provides access to the Internet.
Internet Terminology(Cont’)
• Online Service
– The company provides all sorts of file libraries, chat
services, news services, and so on, within the private
areas of the services themselves.
– The online services sometimes provide two types of
access telephone numbers. One provides you with a
dial-in direct connection to the Internet and access to
the online service. The other provides access to the
online service only, not to the Internet.
Internet Terminology(Cont’)
• Protocol
– Communication protocols provide a similar set of rules
that define how modems, computers and programs can
communicate.
• TCP/IP
– Transmission Control Protocol/Internet Protocol
– A set of Protocols(Communication rules) that control
how data transfers between computers on the Internet.
Internet Terminology(Cont’)
• Shareware
– Software that is given away for free, but which you are supposed
to register (for a fee) if you decide to continue using it.
• Freeware
– Software that is given away with no fee required.
• Demoware
– Software that is generally free, but is intended to get you
interested in buying the “full” program.
Internet Terminology(Cont’)
• HTML
– HyperText Markup Language
– The basic coding system used to create Web documents
• Hypertext
– A system in which documents contain links that allow
readers to move between areas of the document, following
subjects of interest in a variety of different paths. With most
browsers you use the mouse to click a link to follow the link.
Internet Terminology(Cont’)
• LAN
– Local Area Network
– A computer network that covers only a small area
(often a single office or building)
Internet Terminology(Cont’)
• bps
– bits per second
– A measure of the speed of data transmission; the number
of bits of data that can be transmitted each second.
• bit
– A bit is either 0 or1.
– 8 bit = 1 character
Internet Terminology(Cont’)
• Analog Signal
– A signal that varies in a continuous manner, such as
music or the voice tones carried over telephone lines.
• Digital Signal
– An electrical signal which takes on only certain values
(0 or 1) and is not continuous.
Internet Terminology(Cont’)
• Client
– A program or computer that is serviced by another
program or computer.
• Server
– A program or computer that services another program
or computer.
Internet Terminology(Cont’)
• IP Address
– Dot Address
– A 32-bit address that defines the location of a host on the
Internet
– Such addresses are normally shown as 4 bytes, each one
separated by a period (for example, 192.156.196.1)
• Domain Name
– A name given to a host computer on the Internet.
Internet Terminology(Cont’)
• URL
– Universal Resource Locator
– A Web address
Internet Terminology(Cont’)
• Website
– A collection of Web documents about a particular subject
on a host.
• Home Page
– The Web document your browser displays when you start
the program.
– A sort of “main page” at a Website.
• Web Page
– Each web document
Internet Terminology(Cont’)
• Web Browser
– A program that lets you read HTML documents and
navigate around the Web.
• Web Server
– A computer system that makes Web documents
available to Web browser.
• Web Master
– The person who takes care that Website.
Internet Connections
• Permanent Connections
– A connection to the Internet using a leased line.
– If you have a permanent connection, your computer
connects directly to a TCP/IP network that is part of
the Internet.
– A company can lease a single line and then allow
multiple employees to use it to access the Internet.
Internet Connections(Cont’)
• Dial-In Direct Connections
– PPP(Point-to-Point Protocol), SLIP(Serial Line
Internet Protocol), or CSLIP(Compressed SLIP)
connections
– You must have a modem, and you have to dial a
telephone number given to you by the service provider
or online service.
Internet Connections(Cont’)
• Dial-In Terminal Connections
– A Shell Account
– You also have to dial into the service provider’s
computer.
– When the connection is made, your computer simply
becomes a terminal of the service provider’s computer.
Internet Connections(Cont’)
• Mail Connections
– A mail connection enables you to send and receive
Internet e-mail and, perhaps, to read the Internet
newsgroup.
– But you can do nothing more.
Equipment You Will Need
• A Pentium-based PC
– The faster the better, the more RAM the better.
– At least 16M of memory and 200M free hard disk space.
– Providing a nice graphical software.
– At least a 486 PC computer
Equipment You Will Need(Cont’)
•
•
•
•
•
•
A color monitor running at least 800*600 resolution
A sound card with external speakers
Either the Windows 95, 98 or NT operating system
A standard telephone line
An account with an Internet Service Provider
Appropriate Internet software
Equipment You Will Need(Cont’)
• A modem
– A modem takes the digital signals from your computer and
converts them to the analog signals that your phone line uses.
– An External VS. An Internal
– The faster the better
– Most service providers have 33600 bps connections these days
Equipment You Will Need(Cont’)
• A modem(Cont’)
– There are currently 2 rival techniques used for making
modems transmit at 56K speed, and not all service
providers can use both methods.
– Although rated at “56K”, it can transfer from the Internet
with56K but transfer to the Internet will go at the slower
33.6K rate
– It may not transfer at 56K speed across some phone lines.
The Best Internet Service Provider
• A service that you think is good might prove to be a
lousy choice for someone else.
• Basically, what you need to do is pick a service provider
that is cheap, helpful, and has a reliable and fast
connection to the Internet and easy-to-install software.
Getting on the Net
• Install Modem
• Install a connection though Dial-Up Networking
• Connect to the Internet Service Provider