Understanding URL’s

1. Understanding URL’s

2. 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.

3. 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!

4. 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.

5. 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.

6. Dissecting URLs The basic structure of a URL is: transfer protocol://servername.domain ext/directory/subdirectory/filename.filetype

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

8. 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

9. Domain or Domain Extension http://www.library.jhu.edu/elp/useit/evaluate/url.html This 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

10. 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 filename Directories/subdirectories

11. 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)

12. 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.htmlare often home pages 

13. 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.

14. Server or domain name Location within resource Domain extensions Protocol

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