Understanding URL’s

Why must you validate Internet Information?

Anyone can publish anything on the Internet.

Internet resources can come in many different formats and designs and can change at any moment.

Any part of the Internet can become unavailable at any moment.

Tips for evaluating web sources

look for clues ask questions consider the motives of people

publishing on the Internet trust nobody - until you have found

good cause to do so!

Be clear about your purpose!

The Internet may not always be the best source for the information you are seeking.

If you don’t know what you are looking for, you will waste a lot of time in cyberspace.

Get Clues from URLs

The URL can provide a lot of information about a resource and your location within it before you spend time looking at the actual site itself.

Dissecting URLs

The basic structure of a URL is:

transfer protocol://servername.domain ext/directory/subdirectory/filename.filetype

The first part – Transfer Protocol

Indicates what type of information is being transferred and, usually, what port (or "door") to the server is being accessed. Here are the most common types:

http:// Hypertext (the standard format for the World Wide Web)

gopher:// Gopher format (text only precursor of the Web: still good for text-based information)

ftp:// File Transfer Protocol (Whoa! A computer file is about to be sent to your computer. Proceed with caution if this is new to you.)

news: Newsgroup format (something like a special interest bulletin board)

http://www.library.jhu.edu/elp/useit/evaluate/url.html

The Second Part-Server name

The address of the server itself: your message has to go somewhere.

actual name of the server also called domain name

http://www.library.jhu.edu/elp/useit/evaluate/url.html

Domain or Domain ExtensionThis is an important consideration when you are trying to

evaluate an electronic document.

ac, edu academic or educational servers

co, com commercial servers

gov government servers

mil military servers

org non-governmental, non-profit organizations

net service providers

http://www.library.jhu.edu/elp/useit/evaluate/url.html

The Last Part – Directories, subdirectories and filenames

After the machine name, between the next set of slashes (/) you will see the names of directories containing the file you are accessing.

http://www.bps.org.uk/publicat/Periodicals/Psych/PSY9_97.HTM

a complex site is not necessarily a high quality site

Directories/subdirectories

filename

File Type

The last part of the URL specifies the individual document you are looking at. The file extension tells you what type of file you are looking at. Some standard file types include:

.html or .htm: hypertext (the standard for the Web) .gif, .jpg, .bmp: image types .zip, .tar: compressed files (proceed with

caution: these are specially compressed files that will be downloaded onto your hard drive; you need to know if your computer can interpret them)

Finding the Home Page

By deleting part of the right end of an address you will move up the directory tree

URLs ending in:/welcome.html

/index.html/default.html

are often home pages 

The Tilde ~ Sign Use the tilde as a clue! Most Web servers use

the ~ symbol to represent the personal directories of individuals.

If the URL contains a tilde then be aware that you are probably (although not definitely) looking at a personal page with personal opinions rather than an official site giving the official line.

This does not mean that the information is necessarily of poor quality.

ProtocolServer or domain name

Location within resourceDomain extensions

Summary

Use your critical thinking skills to determine if a web resource is the right one for your needs.