Download Chapter 8

Chapter 8
The Internet: A Resource for All of
Us
The Internet
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“network of networks” -- technology for linking
computers into a world-wide network
every connected computer can directly
exchange data with any other computer on
the network
– uses packet switching principles
– each machine has its own unique IP address
– type of computer does not matter
Internet History
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1969 - ARPANET established connections
between 4 computers (UCLA, UCSB,
Standford, Univ of Utah)
1972 - email invented by Ray Tomlinson
1982 - term Internet used to describe a
connected set of networks
1990 - development of the World Wide Web
– Tim Berners-Lee creates a system to
distribute research results over the Internet
Internet organization and
administration
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no controlling authority for the Internet
management of the Internet is
distributed throughout the network
participating computers and networks
agree to implement the Internet
protocols for sharing resources
Why has the Internet become so
popular?
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universal TCP/IP standard
ability to link sites (Web)
easy access to resources via graphical
browsers
increased use of PC’s and networks at
work and home
Accessing the Internet Client/Server
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server - software and/or hardware installed on the
computer where the information being accessed is
stored
– allows the user to get the information
– the computer system being accessed may be
anywhere in the world
client (browser) - the piece of software that requests
information from the server
– runs on user’s computer
– Mosaic - first graphical browser - Marc
Andreessen
– Netscape, Internet Explorer
Web Terms
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Web server - software that responds to
client (browser) requests
Web site - collection of related Web
documents
home page - document first
encountered at a particular Web site
(usually an index or table of contents)
Browser Terms
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default start page - located at the browser
vendor’s home server
– can be changed
history list - list of previously viewed sites
– quick way to go back to a particular site
favorites/bookmarks - allows user to save
addresses of frequently visited sites
plug-ins - software that enhances the
capability of a browser to access Web
resources
Web addresses
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URL (Uniform Resource Locator) - an address that
uniquely identifies the location of a Web document
URLs have 4 parts: (not all parts are required)
– protocol - Internet standard used to access document (http,
ftp, gopher, etc.)
– server - Internet domain name of the server on which the
document is located
– path - specific directions for finding the document on the
computer (folders and subfolders)
– resource name - actual filename of the document
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http://www.asu.edu/it/fyi/menus/consulting.html
Finding Information on the Web
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subject guides (directories) - lists of sites organized
by content and selected by human researchers
– examples: www.yahoo.com, www.vlib.org
search engines -software that allows users to search
databases that index large portions of the Web
– searches often hampered by ambiguity of English
language
– search operators and words not fully standardized
– examples:AltaVista, Google, Infoseek, Lycos
Reliability of information on the
Web
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Just because something is on the Web does
not make it true. Ask yourself some of these
questions.
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Who wrote the page?
Who sponsored it?
What is the purpose?
Is it objective?
Are the sources reliable?
Is the data accurate?
Is the data up-to-date?
Other parts of the Internet
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Usenet - informal network that allows the posting and
reading of messages in newsgroups that focus on
specific topics
FTP (file transfer protocol) - a standardized method
for transferring files
– downloading - transferring a file from the remote
(server) system to your local machine
• can result in a virus infecting your computer
– uploading - transferring a file from your local
machine to the remote (server) system
telnet - software that allows a PC to connect to a host
computer on the Internet and emulate a local terminal
Electronic mail
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created by Ray Tomlinson in 1972
mail server - receives and stores
incoming mail
e-mail client - software running on your
computer; allows user to read,
compose, send, save, delete and print
messages
e-mail address - user@domain
E-mail Addresses
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addresses have 2 parts connected by
the @ symbol
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user name (mailbox name)
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domain name (server address)
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identifies owner of e-mail account
identification of the computer system on which
your account resides
examples: [email protected]
[email protected]
Netiquette
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Netiquette - term coined to describe appropriate
behavior when using the Internet
– E-mail examples
• include a brief, meaningful subject line
• don’t write in anger (flame)
• be aware that attachments can be used to transmit
viruses
• never respond to junk email (spam)
• use emoticons (smileys) to help communicate meaning
ex: ;-)
:-( :-o
– other examples
• observe copyright restrictions
• observe privacy and system use rules
What you should know
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you may not have a right of privacy at
work or at school
backup copies of email are sometimes
kept for several years
written communication is NOT the same
as oral communication
– emoticons can help clarify meaning
E-mail accounts at UNLV
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Computer accounts can be generated on
Pioneer
– mainframe that runs Unix OS
– assigned a login and password
• login becomes the user name portion of your
e-mail address
• e-mail address is [email protected]
• password can be changed on Web
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Once an account is set up you will have
access to e-mail on the Web
– https://webmail.scsv.nevada.edu/