Transcript PowerPoint - Columbus State University

The World at Your Fingertip
- The Internet
Shamim Khan
Columbus State University
TSYS Department of Computer Science
What is the Internet?
• A global network of computer networks
• Every connected computer can exchange
data with any other connected computer
• Used to communicate, find information,
learn, seek jobs, do business
• Owned by nobody (or everybody)
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How the Internet was born
1972: ARPANET A few universities and government
agencies sharing data
1978: IPSS First international packet switched network
Grows from Europe & the US to cover Canada, Hong Kong
and Australia by 1981
Late 1980s: The name Internet gains popularity
1990s: Internet spreads worldwide
1992: US Government pulls out
Businesses start offering public access
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How the Web was spun
1989: Created at CERN, Geneva
 1992: First text-based Web browser released in
 1993: Developed into Mosaic browser at the
NCSA
 1994: Netscape Navigator becomes the dominant
Web browser
 1995: Microsoft enters market with Internet
Explorer
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The Internet and Web
- What’s the difference?
• The Internet
- the infrastructure: the physical connection of
millions of networks
• The Web
- A collection of interconnected documents, linked
by hyperlinks and URLs.
- Accessible via the Internet
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What is a Web Site?
• A Web site is a collection
of related Web
documents
• The index page, or home
page, is the top-level
page of a Web site.
• Web pages are individual
documents (files) on the
web server
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The Hyperlinks Concept
• A reference in a
document to another
document
• Selecting a hyperlink
causes the computer
to load and display the
linked document.
• Hypertext: Text
documents with
hyperlinks
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Hypermedia
• Hypermedia extends hypertext to
multimedia such as music and movies
• The Web is a distributed hypermedia
system
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Web Browsers and Web
Servers
• Web browsers
– display a web document and
– enable users to follow links to other Web
pages.
• Web servers
– respond to requests from browsers.
– find and send requested resources back to the
browser.
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Web Addresses (URLs)
• Web addresses identify where a Web
resource is located.
• The uniform resource locator (URL): the
standard used to identify Web resources.
• The URL consists of:
Protocol
identifies
the means
of access
Server contains
the domain
name of the
Web server
Path
identifies the
location of the
document
Resource
specifies the
filename of the
resource
URL http://www.yahoo.com/ help/shop/ shop-01.html
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Internet Protocols
• Transmission control protocol (TCP) –Defines
how one computer can communicate with
another computer on the Internet
• Internet protocol (IP) – Defines the Internet’s
addressing scheme
• IP address – Each computer connected to the
Internet is given an address composed of
numbers and periods.
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Example: 209.234.156.8
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Domain Names
Domain Name
• Domain Name System (DNS) – Enables users to
type names of Web sites and Web pages as well
as IP addresses. Example: www.hsnqp.com or
112.23.345.56
• The last part of the domain name gives the type of
organization that maintains the site. Examples:
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.com, .net, .edu, and .gov.
Internet Services: E-Mail
- Staying in Touch
• E-mail (Electronic mail) – the most popular of
the Internet services.
• Messages with file attachments sent and
received in seconds.
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Internet Services: IRC - Text
Chatting in Real Time
• Internet Relay Chat supports real-time, textbased conversations.
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Internet Services: File Transfer
Protocol (FTP)
DOWNLOAD
UPLOAD
Your Computer
(Client)
FTP Server
• FTP is a service that enables client
computers to directly copy files to and from
a server
• Uses an FTP serverCSTAA
software (eg. WinFTP)15
Internet Services: Telnet
• Telnet— A protocol that lets you directly
access certain computer systems on the
Internet.
• Unlike other Net resources that provide
access to a computer's files, Telnet lets you
use the system's own command-line
interface.
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Internet Services: Usenet
• Internet service which enables users to
participate in discussions
and newsgroups.
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Internet Services: Listservs –
Emailing Lists
• A listserv is an
automatic list server.
• Mail sent to
everyone on the list
when e-mail is
generated.
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Internet Services: Telephony
(VOIP)
• Internet telephony (Voice Over IP) allows realtime conversations via the Internet instead of a
circuit-switched telephone network
• This can be extended to phone + video for video
conferencing
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Finding Information on the Web
• Searching the Web –
Involves using search
engines to locate Web
pages with the information
you’re looking for
• Search engines maintain
databases of Web pages
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Using Search Engines
• Choose a search engine (Google, Alta-Vista,
Yahoo, etc)
• Type in one or more words describing your
topic
• The search engine checks its database for
Web pages that contain the words typed
• Links to relevant pages are sent to your
computer
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In Summary …
• The Internet and the World Wide Web have a fairly
recent history
• Next to printed text, no other invention has
contributed more to the spread of knowledge and
understanding
• The Internet and the Web have much more to offer
in services and tools than most of us are aware of
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