Library 102 First Class Session

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 | Library 102 Syllabus |

Introduction to the Internet

What is the Internet? VERY BRIEFLY, the Internet is an international, decentralized network of computer networks  running on the protocol  (communications rules) called TCP/IP. A computer network consists of  two or more computers connected in order to share information. When two or more networks are connected, it is called an internet. THE Internet is the largest internet in the world connecting millions of computers from virtually every nation on earth. How does TCP/IP make the flow of information on the Internet possible?

What is the Web? VERY BRIEFLY, the World Wide Web is a collection of hypermedia documents accessed through the Internet. For more information about the Web, click on the link About the Web on the Internet 101.org page.

The Web site Internet 101 also gives a brief historical background to the Internet. The site The Living Internet provides a more detailed history of the invention of the Internet. A very detailed timeline of the development of the Internet, is available at Hobbes' Internet Timeline.

DNS and URLs

Domain Name

Each computer connected to the Internet has what is called an IP address (Internet Protocol Address). The IP address is called a "dotted quad " because it is written in a group of 4 numbers separated by periods (Called dots). An IP address or dotted quad looks like this: 198.189.24.2 . Because it would be difficult to remember these numerical IP addresses, the domain name system (DNS) was developed. The domain name system gives a descriptive name to the numerical address making it easier to remember.

 The parts of a domain name are also separated by periods. The most specific part of the domain name, which is the host computer also known as the server is on the left. In this example, www.cos.edu, the host computer is www. Most servers have a name, but not all Web servers are called "www". The most general part of the domain name is always on the right. In this case, us standing for United States, is much broader in scope than a specific server at a specific college. The broadest part of the domain name, which usually specifies a geographical location such as us for United States or uk for the United Kingdom or a type of organization such as .edu for a college or university or .gov for a government site, is called the top-level domain. The top-level domain helps to identify  where the information is coming from. It is also a key factor in evaluating a web site. The primary top-level domain abbreviations currently in use are as follows:

URL

URL is an acronym for Uniform Resource Locator. The Uniform Resource Locator (URL) is a specific address on the web. URLs are written without spaces and the parts are separated by special punctuation. URLs show in the Address Box  of the Web browser. For example, the URL for this class is:

http://www.cos.edu/library/Lib102/library102syllabus.htm

The URL consists of the following:

Type of transfer://servername.domain/directory/subdirectory//filename.filetype

Another way of saying it is:

How-to-get-there://where-to-go/what-to-get

The structure will always be the same, although there may not always be a subdirectory.

URL Example:

http://www.cos.edu/library/Lib102/library102syllabus.htm

The Protocol* or type of transfer is given first, followed by a colon slash slash:    http://  

Then the Domain Name ( the location of the page):    www.cos.edu      

Then the Directory (and/or subdirectory):    library/Lib102/
Directories and subdirectories are followed by a slash.
 

Then the File:    library102syllabus
The file name specifies the individual document you are accessing.

Then the File Type is last:    .htm
Sometimes the file type will be .html
Both file types: .htm and .html signify the file type for hypertext (web pages)

*http is the protocol for the World Wide Web; other protocols are available through the Internet. The protocols are as follows:

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Date Last Updated:02/22/07
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