Session I - Uniform Resource Locators - An Overview
Conventions for Naming Individual  Pages:

Since web pages get displayed on a wide variety of computers and with various browsers, naming and organizing the individual pages should follow a few rules.  This will ensure that the web site is more easily maintained as well as make the pages viewable with a greater level of predictability on other machines.

• Put all files associated with a web site in a single folder or subdirectory on the computer storing the files
• Create a folder/subdirectory inside this main folder and call it "Images".   Place image files inside that sub folder.
• Begin all file names with an alphabetic character. 
• Use only alphabetic characters, numeric characters, and possibly the dash or underscore character in file names
• End every file name with ".htm" or possibly ".html".  PC computer users should definitely choose the first of these options.  Also notge, many editors (such as FrontPage) automatically add the ".htm" at the end of a file name when saving.

Parts of a URL explained:

URLs (Uniform Resource Locators) allow all resources on the Internet to be identified with a common addressing system. Here is how they are constructed.  The address contains several basic parts:

• service - This refers to a communications service to be used on the Internet.  These include telnet, file transfer protocol, gopher, mailto, etc.
• hostname - This refers to either a numeric code assigned to a server-computer on the Internet or a name given to that same computer.  This unique name or number allows the specific server to be located on the Internet.
• port - This refers to an optional designation which accompanies the hostname and determines which "port" on that computer is to be accessed.   Since standard ports are used for many web services, this part of a URL is often not used as part of the address.
• directory-path - This refers to the name of the directory, subdirectories, and eventually the file to be accessed.  Each level of directory/subdirectory/subdirectory/file is separated by a /.

An example of the parts put together in a generic model would look like this:

service:// hostname: port/ directory-path

Hypertext URLs:

Below  is a more specific example of a URL which accesses hypertext files at a computer whose name (domain name) is "www.zdnet.com".   The directory being accessed on this computer is "macuser".   Finally, no file name is specified after the final / because many servers will automatically access a default page within a directory if no file name is given:

http://www.zdnet.com/macuser/

Common HTTP File Types:  The com part of the address is called the zone and indicates a commercial site.  Other common zones include gov for government, edu for education, org for nonprofit organization, and so forth.

Other URL Types

An FTP URL:  FTP is the file transfer protocol service on the Internet.  It is a protocol for allowing large files to be downloaded from a server to the accessing computer.  Many web browsers will allow us to reach an FTP address and a menu of directories and/or files will be displayed.  The example below also includes a subdirectory which is commonly used for storage of files available for download to the general public - the subdirectory "pub".  Try to access the information at the following site using its ftp address:

ftp://gatekeeper.dec.com/pub

Some FTP sites require a username and a password.  The modified example below shows how those are to be included in the URL for access to restricted areas:

ftp://aname:password@gatekeeper.dec.com/pub

A Gopher URL:  Gopher is the protocol used for transferring text documents from a server to a remote computer screen for viewing.  Before the world wide web and hypertext, many text documents were placed in "gopherspace".   In fact, some projects were intended to place all public domain texts on the the Internet.  Here is an example of accessing a gopher site using its URL:

gopher://wiretap.spies.com/1/Books

A slightly more complicated address might look like this:

          gopher://boom.micro.umn.edu/0/gopher/Mac-TurboGopher/helper-apps/Anarchie-140.sit

A few final reminders: URLs should never contain spaces and are case sensitive even if filenames on your own computer are not.  Some computer systems (PCs or files with DOS underlying operating systems) open files based on a three-character extension on the end of the file name.  For this reason, it is a good idea to name text files intended to serve as web pages with the ".htm" or ".html" extension.  If using a web authoring tool on a PC, it is likely that the extension will automatically be added.  For further information, check out the Learn the Net web site and its explanation of URLs.

[Session 1]  [Session 2] [Session 3]  [Session 4]  [Session 5] [HomePage Overview]  [Top]
This site copyrighted (2005) by Dr. Blake West - Please credit when linking to the site!
Kansas NEA - 715 SW 10th Ave.  Topeka, KS  66612.