Study Material for the Internet

The Internet is a network of networks that connects computers around the world. It grew out of a U.S. Department of Defense experimental project begun in 1969 to test the feasibility of a wide area (long distance) computer network over which scientists and military personnel could share messages and data. The proposed solution was to create a network with no central authority. Each node would be equal to every other node, with the ability to originate, pass, and receive messages. The path that a particular message took in getting to its destination would not matter. The message would be passed from node to node until it reached its destination. Know originally as the ARPANet, the original network of four computers has grown to include tens of millions of computers. It is impossible to determine just how large it really is. It spans the globe, connecting people from all walks of life, from all cultures, from all nations, and from all interests.

The Internet is a network of networks of computers. It provides two basic capabilities, information retrieval and worldwide communication. A subnet of the Internet known as the World Wide Web or Web, is truly unique. It allows information (text, graphics, audio, & video) to be shared among computers which have browsers and a connection to the Internet. Documents can be posted on one computer and read by another anywhere in the world. Each document can contain hyperlinks to other documents which may be on the same computer or on a different computer. The hyperlinks may reference graphic, sound, and video files in addition to text files. Documents in the Web are written in html (HyperText Mark Up Language) This universal language is read by the browsers (e.g. Internet Explorer and Netscape) Computers in the Web are accessed by their URL (uniform resource locator). A URL is a web address. A server computer has a URL and a computer that connects to the server is called a client. A client may be a server and a server may be a client. A URL has the form: transfer method, Web site address, directories, documents. For example http://dogs.about.com/pets/dogs/msub13.htm      In general, servers reside on networks called com, net, org, or edu, to name a few.

In order for the Web to work, every client must be able to display the documents from every server. This is accomplished by imposing a set of standards, known as a protocol, to govern the way data is transmitted across the Web. This protocol is known as the HyperText Transfer Protocol or http.

In order for a server to be accessed or a client to access a server, each must have a connection to the Internet. An ISP (Internet Service Provider) typically provides this service for a server or a client.

Search Engines are programs which help the client find a server on the Web which has the information they are seeking. They search a database of web sites, in response to a keyword search request (query). The engine returns titles and/or abstracts of documents it finds, together with a link to each document or site. In order to keep their database of web sites as current as possible, the search engines use a spider program which continually searches the Web for new pages and adds them to the data base.

There are many different search engines and they will return different lists of sites in response to the same query. The single most successful guideline for a successful search is to use multiple search engines. Each search engine (Yahoo, Dogpatch, Google, etc) has their own database of information and links. Items returned as matching your query are called hits. You can limit the number of hits and be more successful and efficient in your search by giving some thought to the keyword/s used in the query and taking advantage of the Boolean Operators And, Or and Not. For example, American or Airlines is not as efficient as American Airlines since American or Airlines would return information about American, information about Airlines and information about American Airlines (much more than you intended) while American Airlines would return information about the airline only.  The way in which you specify the Boolean operator depends on the search engine and is described in its online help.

Copyright Protection on the Web is the same as copyright protection in any print media. You should assume that every thing on the Web is copyright unless it says it is in the public domain. Copyright gives the author excusive rights to the use and reproduction of written or artistic work, except as governed under the fair use exclusion. It is considered fair use to use a portion of a work for educational or nonprofit purposes or for the purpose of critical review or commentary. Facts are not covered by copyright so you can use statistical and other data with out fear of infringement. You can quote a site, or download an image or other information from the Web, provided you cite the original work in your footnotes and/or bibliography.

Be sure to cite the original source when using facts and/or copyright material from a web site.

eComerce is the exchange of goods and services over the Internet, usually via the Web. Cookies are small files that are placed on the client computer by a server. Cookies make it possible to personalize the client’s interaction with the server. They can also compromise the privacy and security of the client’s computer.

The Internet is transforming the world.   It is perhaps, after the invention of the computer itself and the Integrated Circuit which made personal computers possible, the most important invention of the twentieth century.