Understanding a URL

Sections:
1) Introduction
2) Web Directories
3) Search Engines
4) Understanding a URL
5) Five Types of Webpages
6) Evaluation Criteria

Understanding a URL (Web Address)
Every Web page has a unique address called a URL (Uniform Resource Locator) which identifies where it is located on the Web. For example, the URL for CSM Library's home page is: http://www.smccd.edu/accounts/csmlibrary/index.htm

The basic parts of a URL often provide "clues" to where a web page originates and who might be responsible for the information at that page or site.

URLs have three basic parts: the protocol, the server name and the resource ID. Look again at CSM Library's URL below to see these three parts. The protocol is shown at the beginning of the URL before the double slash (//); the server name is between the double slash (//) and the first single slash (/); and the resource id is everything after the first single slash (/).

http://www.smccd.edu/accounts/csmlibrary/index.htm
protocol | server name | resource id

Let's examine each part of this URL:

First part: protocol (http://)
The protocol identifies the method (set of rules) by which the resource is transmitted. All Web pages use HyperText Transfer Protocol (HTTP). Thus, all web URL's (including CSM Library's) begin with http://.

Second part: server name (www.smccd.edu/)
The server name identifies the computer on which the resource is found. (Computers that store and "serve up" Web pages are called remote servers.) This part of the URL commonly identifies which company, agency or organization may be either directly responsible for the information, or is simply providing the computer space where the information is stored. Web server names often begin with the letters www, but not always.

The server name always ends with a dot and a three-letter or two-letter extension called the domain name. The domain is important because it usually identifies the type of organization that created or sponsored the resource. Sometimes it indicates the country where the server is located. The most common domain names are:

* .com which identifies company or commercial sites
* .org for non-profit organization sites
* .edu for educational sites (most commonly four-year universities)
* .gov for government sites
* .net for Internet service providers or other types of networks

If the domain name is two letters, it identifies a country, e.g. .us for the United States, .uk for the United Kingdom, .au for Australia, .mx for Mexico or .ca for Canada.

The server name for our library's Web site is: www.smccd.edu. The server name may also be the name of a Web site. (A Web site is a complete group of Web pages that are organized as a comprehensive set.) Web sites can be either all of the pages on one server (computer) or all of the pages under a specific subdirectory on a server. For CSM Library, the server name (www.smccd.edu) identifies the San Mateo County Community College District. The CSM Library Web site consists of all of the pages under the subdirectory: /accounts/csmlibrary.

Third part: resource ID (/accounts/csmlibrary/index.htm)
The resource ID is the name of the file for the page and any directories or subdirectories under which it is stored on the specified computer. The resource ID for our library's homepage is: /accounts/csmlibrary/index.htm. (A "homepage" is the opening or main page for any web site that provides links to all of the other pages on the site.) The part of the resource ID after the last slash (/) is the file name for the specific page or other resource. The file name ends with a three or four letter designation that specifies the file type (e.g., .htm or .html for a standard Web page, .jpg or .gif for common graphic files.)

Adapted from:
College of San Mateo, LIBR 105: Online Research Skills
Skyline College, LSCI 100: Introduction to Information Resources