Transcript Chapter 8
Chapter 8 The Internet: A Resource for All of Us The Internet “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 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 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? 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 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 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 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 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 http://www.asu.edu/it/fyi/menus/consulting.html Finding Information on the Web 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 Just because something is on the Web does not make it true. Ask yourself some of these questions. – – – – – – – 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 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 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 addresses have 2 parts connected by the @ symbol user name (mailbox name) domain name (server address) identifies owner of e-mail account identification of the computer system on which your account resides examples: [email protected] [email protected] Netiquette 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 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 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 Once an account is set up you will have access to e-mail on the Web – https://webmail.scsv.nevada.edu/