WHAT IS GOPHER?

                     Gopher is a communications method or protocol for retrieving text and file-based information from the Internet. Designed at the University of Minnesota, gopher quickly became an Internet standard. When gopher was first developed, the programs that used this method for accessing Internet information were also called Gopher. Today, programs that use this method of retrieval are referred to as Gopher Clients. The program called Gopher is also considered a Gopher client. The Gopher protocol is designed to allow easy access to text and file-based information that is distributed across different machines on the Internet. Gopher allows you to connect to remote computers known as Gopher Servers and browse the information that has been made available on them. Typically, you use Gopher by starting at a local machine, and following connections from that machine out to other source of data. At each new machine, there are often connections to other computers. This interconnection of data and machines was the precursor to what has come to be called the World Wide Web.

THE WEB IS BORN

                      In March 1989, Tim Berners-Lee of Geneva’s European Particle Physics Laboratory (CERN- Conseil Europeen pour la Recherché Nucleaire) proposed to develop a hypertext system to enable easy information sharing among the High Energy Physics community regardless of the country they were in.

The three components of the hypertext system were:

                     A consistent user interface. The ability to incorporate a wide range of technologies and document types. Universal readership. (Universal readership enables anyone on the network using a wide variety of computers, to read the same documents easily.)

                     In October of 1990 the World Wide Web began to take shape when the CERN labs began working on the first graphical hypertext delivery system also known as a Web browser. In November 1992 the CERN list of “reasonably reliable servers” comprised 26 servers at sites around the world. In January 1993, 50 web servers were in existence and the Viola browser was made available for X Windows systems. In February 1993, Mosaic was developed by Marc Andreessen at NCSA (National Center for Supercomputing Applications) in the United States at the University of Illinois. In 1994, Andreessen and some of the Mosaic team left NCSA to form Netscape with Jim Clark where they developed and released a commercial Web browser called Navigator for free on the net. In the same year the work of having secure Web access started. Security was required if people were to provide credit card information on the Web. To develop the Web further, CERN turned over the Web project to the W3 Organization in July 1994.The W3 organization was a joint effort between CERN and MIT.

WORLD WIDE WEB

                     The World Wide Web (also known as the Web, WWW, and sometimes W3) is the area of the Internet that has received tremendous focus in the last few years. Many people new to the Internet, think that the Web *is* the Internet. However, the Web is just part of the Internet, albeit a very major part. The Web is made up of “sites”-a site being where someone has placed files that can be accessed by those connected to the Internet. The files are of all different types – text, graphic, video, sound, etc. – and they are on computers around the world. They constitute a vast amount of information on several subjects.

                     The files are accessed by using IP addressing and a specific protocol called http, which stands for Hypertext Transfer Protocol. The Web works on the client/server model. You use a client program which passes your request for information to a server. The server obtains the information and passes it back to your client. The client software that you use to access the Web is called a browser. Popular browsers are Netscape Navigator and Microsoft Internet Explorer. With all of these browsers, you can see graphic files on the Web. There are some text-only browsers, such as Lynx.

WWW BROWSER

                     A Web browser is a program that you can use to view files on the Internet, including images, text, sound and video. A graphical Web browser is a browser that enables you to view Multimedia content such as images, audio, and video, on the Internet. The first graphical Web browser was “Mosaic” that was developed in 1993 by the National Center for Supercomputing Application at the University of Illinois. Mac Andreessen and six fellow students developed the program for creating the Mosaic browser while working on a university-sponsored computer project. This program has contributed immensely to developing and propagating the World Wide Web to the forefront of Internet tools. Mosaic converted the text only WWW into an environment that is similar to Microsoft Windows. With the introduction of Mosaic, the total amount of data transported though the Web increased by a factor of 10,000 within six months.

WEB SERVER

                     A web server is the computer that stores web pages or an application that resides on the server. The computer and the server refer to the hardware components while the application is the software component. The server transmits graphics, audio, and video to web browsers. Web servers are also called HTTP servers because they use the Hyper Text Transfer Protocol (HTTP) to serve web pages to web browsers.

                     A connection between the web browser and the web server is called ‘stateless’. This is because when you send a request for a web page to a web server by using the browser, the server checks for the validity of the request for an HTML document. Then the server sends the requested web page to your web browser and the connection is closed. The web browser connects to the web server only when a request for the web page to be reloaded or refreshed is submitted. You can avail of Web servers by paying for them, known as commercial Web servers. Alternatively, you can use the free Web servers that are called Freeware, Microsoft Internet Information Server (IIS) ® and Netscape web server are among the most popular commercial web servers. Apache® is a popular Freeware.

WHAT IS HTTP?

                     HTTP, the Hypertext Transfer Protocol, is the application-level protocol that is used to transfer data on the Web; HTTP comprises the rules by which Web browsers and servers exchange information over a TCP/IP connection. An HTTP server is a program that listens on a machine’s port for HTTP requests. An HTTP client or web client opens a TCP/IP connection to the server via a socket, transmits a request for a document, and waits for a reply from the server. After the request-reply sequence is completed, the socket is closed. So the HTTP protocol is a transactional one. The lifetime of a connection corresponds to a single request-reply sequence that is known as a transaction.

HOW DOES HTTP WORK?

HTTP Is a request-response protocol.

The request comprises

–        a request line

–        a set of request headers

–        an entity

The server sends a response that comprises

–        a status line,

–        a set of response headers, and

–        an entity.

                     The entity in the request or response can be though of simply as the payload, which may be binary data. The other items are readable ASCII characters. When the response has been completed, the browser or the server may terminate the TCP/IP connection, or the browser can send another request.

WHAT IS A URL?

                     URL is the abbreviation of Uniform Resource Locator. AURL is the global address of documents and other resources on the World Wide Web. The first part of the address indicates the protocol and the second part specifies the IP address or the domain name where the resource is located. For example, the two URL’s below point to two different files at the domain www.nyise.org. The first specifies a file located in the subdirectory “fanny” of the NYISE web site; the second specifies a Web page that should be fetched using the HTTP protocol:

http://www.nyise.org/fanny/index.html

http://www.nyise.org/index.html

WHAT IS A SEARCH ENDINE?

                     A Search Engine is used to find information on the Internet when you don’t know where to start. Search engines allow users to enter keywords to find Internet sites. Search Engines use “robots” or “crawlers” to find and index words that appear on web sites. The Search Engine then matches the keywords in the search to the words in its index. The different search engines that are available are www.google.com, www.altavista.com, www.hotbot.com, www.yahoo.com, www.askjeeves.com etc.

METASEARCHERS OR CRAWLERS

                     Metasearchers or crawlers offer the possibility to do a search without having to consult every search robot separately. They function as an intermediary, by passing on the query to the search robots and afterwards order the results.

THIS HAPPENS IN TWO WAYS:

                     The first type presents the various search robots together on one page, each with their own text box. The user subsequently chooses a particular search robot. The advantage of such a page is that you can immediately go the Metasearch page and choose another search robot.

                     The second type offers the possibility to type in a query once and then indicates in which database of which robot(s), the search is to be carried out. The query is then simultaneously submitted to the chosen search robots. The results are presented either in a long list sorted according to relevance or as a list per search robot that is then sorted according to relevance.

SEARCHING CRITERION

Quotes

                     Placing words within quotation marks (“) creates a phrase. The search engine returns a match only when the engine finds the exact word sequence. Example: “minnesota trade office”

Asterisk

                     An asterisk (*) is also known as a wild card; it must be placed on the right-hand side of a word or embedded within a word. Normally sites require at least three characters to the left. You can use an asterisk to find various spellings or related words. Example: export^* would return matches of export, exports, exporter, and exporting. 

AND operator

                     Search results must contain all words joined by the AND statement. Example: commercial AND service.

AND NOT operator

                     Search result cannot contain the word that follows the AND NOT statement.

                     Example: software AND NOT integrator will find sites about software itself but eliminate sites about software integrator

OR operator

                     Search results must contain at least one of the words joined by the OR statement. Example: distributor OR agent lists sites that contain either word.

Plus

                     Adding a plus sign (+) directly in front of a word requires that the word be included in all search results. Place the plus sign between two words in a multiple word search.

                     Example: export+assistance

Minus

                     Adding a plus sign (+) directly in front of a word indicates that the word should not be found in search results, Example: commerce-chamber

Parentheses

                     Use parentheses to build complex search queries that incorporate other special words and characters. Example: NAFATAAND (Canada OR Mexico) lists sites about either country pertaining to NAFTA.