Download Information on the Internet

Information on the Internet
http
• hypertext transfer protocol
• Web clients (browsers) make request to the
web server.
• Looks for web page written in HTML.
URL
• Uniform Resource Locator
• Entire location of a page/image:
• http://www.amazon.com
http://keep3.sjfc.edu/faculty/jsarachan
http://www.amazon.com/exec/obidos/searchhandle-form/102-3711441-9976104
http://www.sjfc.edu/admissions/academics.asp
http://www.hammersaw.com/logo.gif
Parts of a Domain Name
• Top Level (TLD)
.com, .edu, .net, .gov, .org, .biz, .info
.ca, .uk, .tv
• Second Level
• Third Level (www)
IP Address/
Domain Name System
• IP Address has 4 parts: 64.236.16.20
• D omain name system links URL to IP address
via DNS servers
• DNS=Domain Name System
• Static vs. Dynamic IP addresses
How Search Engines Work I
• A search engine uses a form of software that can
travel on the web called a “crawler” or “spider” or
“bot.”
• Examines each page, and each link (some ignore
images, pdf files, etc.).
• Information about each page (everything or
headings, keywords) are sent back to database.
• Webmasters can submit site to speed up process.
How Search Engines Work II
• User submits keywords that match
keywords from the site, as well as dates
created or other criteria.
• Information from database is returned,
ordered by different rules (relevance, age).
• User may be given title and URL and/or
sentences about document (meta tags).
Optimization of Web Sites
• Web Designers should pick obvious names
for the URL—without hypens or
misspellings.
• Use meta tags.
• Frequency of keywords on page.
Finding Web Sites
• Use different rules (algorithms) to organize web
pages.
• Keyword frequency/placement/prominence
• Fuzzy search
• Relevance (order of keywords matter)
• Site popularity
• Paying for Placement
• Boolean logic
Two type of search sites
• Directories (indexes)
• Search Engines
Google
• http://www.google.com
• Works as phone book:
combination of first and last name, city, state
OR phone number
• Finds street maps via yahoo or mapquest
• Dictionary definitions
• Stock quotes (to yahoo)
Typical Rules
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“spider man“ (include whole phrase)
Spider -man (don’t include this word)
Spider ANDNOT man(don’t include second word)
(spider man) (one word or the other)
Spider OR man (one word or the other)
+spider +man (both spider and man)
Spider AND man (both spider and man)
Searching Extras
Google
• biology site:www.sjfc.edu
• link:www.sjfc.edu
• Info:www.sjfc.edu
• Advanced Search (and tips) in Google
Other search engines
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www.yahoo.com
www.findarticles.com
www.dogpile.com
www.askjeeves.com
www.beaucoup.com (free information)
www.kartoo.com
www.archive.org
Things You Can Find on the Internet
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Websites
Images
MP3 files
News
Maps/directions (www.mapquest.com)
People(www.switchboard.com,whitepages.com,
yahoo.com)
Games (www.gamespot.com)
Film or TV show information (www.imdb.com)
Music Information (www.allmusic.com)
Lyrics (type into Google)
Health Information (www.webmd.com)
Bookmarks
• Also called Favorites
• In IE, if you are on a page you want to keep,
choose: “Add Page to Favorites”
• You can organize favorites and add URLs to
toolbar.