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Internet - Introduction to Internet, Important Definition, Components of Internet

Introduction to Internet
 
Introduction
 
By the turn of the century, information, including access to the Internet, will be the basis for personal, economic, and political advancement. The popular name for the Internet is the information superhighway
 
Whether you want to find the latest financial news, browse through library catalogs, exchange information with colleagues, or join in a lively political debate, the Internet is the tool that will take you beyond telephones, faxes, and isolated computers to a burgeoning networked information frontier.
 
The Internet is a computer network made up of thousands of networks worldwide. No one knows exactly how many computers are connected to the Internet. It is certain, however, that these number in the millions and are growing.
 
No one is in charge of the Internet. There are organizations which develop technical aspects of this network and set standards for creating applications on it, but no governing body is in control. The Internet backbone, through which Internet traffic flows, is owned by private companies.
 
All computers on the Internet communicate with one another using the Transmission Control Protocol/Internet Protocol suite, abbreviated to TCP/IP. Computers on the Internet use a client/server architecture.
 
This means that the remote server machine provides files and services to the user's local client machine. Software can be installed on a client computer to take advantage of the latest access technology.
 
An Internet user has access to a wide variety of services: electronic mail, file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, breaking news, shopping opportunities, and much more.
 
The Internet consists primarily of a variety of access protocols. Many of these protocols feature programs that allow users to search for and retrieve material made available by the protocol.
 
 
 
What is the Internet?
 
The Internet links are computer networks all over the world so that users can share resources and communicate with each other. Some computers, have direct access to all the facilities on the Internet such as the universities. And other computers, eg privately-owned ones, have indirect links through a commercial service provider, who offers some or all of the Internet facilities.
 
In order to be connected to Internet, you must go through service suppliers. Many options are offered with monthly rates. Depending on the option chosen, access time may vary.
 
The Internet is what we call a metanetwork, that is, a network of networks that spans the globe. It's impossible to give an exact count of the number of networks or users that comprise the Internet, but it is easily in the thousands and millions respectively.
 
The Internet employs a set of standardized protocols which allow for the sharing of resources among different kinds of computers that communicate with each other on the network.
 
These standards, sometimes referred to as the Internet Protocol Suite, are the rules that developers adhere to when creating new functions for the Internet.
 
The Internet is also what we call a distributed system; there is no central archives. Technically, no one runs the Internet. Rather, the Internet is made up of thousands of smaller networks.
 
The Internet thrives and develops as its many users find new ways to create, display and retrieve the information that constitutes the Internet.
 
Internet
 
• A network of networks
 
Based on TCP/IP (Transmission Control Protocol/Internet Protocol)
 
Global
 
A variety of services and tools
 
A network of networks, or "internet," is a group of two or more networks that are: Interconnected physically capable of communicating and sharing data with each other able to act together as a single network
 
Machines on one network can communicate with machines on other networks, and send data, files, and other information back and forth.
 
For this to work, the networks and machines that are part of an internet have to agree either to speak the same "language" when they are communicating or to use an "interpreter."
 
This "language" is software that enables the different types of machines on separate networks to communicate and exchange information.
 
To be used by different types of machines yet be understood by all of them, the software must follow a set of rules, or protocol.
 
The Internet, with a capital "I", is the network of networks which either use the TCP/IP protocol or can interact with TCP/IP networks via gateways (the interpreters).
 
The Internet presents these networks as one, seamless network for its users
 
The Internet covers the globe and includes large, international networks as well as many smaller, local-area networks (LANs).
 
 
The Internet offer access to data, graphics, sound, software, text, and people through a variety of services and tools for communication and data exchange:
 
Remote login (telnet)
 
file transfer (ftp)
 
electronic mail (e-mail)
 
news (USENET or network news)
 
hypertext (WWW)
 
 
 
History & Development of Internet
 
In its infancy, the Internet was originally conceived by the Department of Defense as a way to protect government communications systems in the event of a military strike
 
The original network, dubbed ARPANet (for the Advanced Research Projects Agency that developed it) evolved into a communications channel among contractors, military personnel, and university researchers who were contributing to ARPA projects.
 
The network employed a set of standard protocols to create an effective way for these people to communicate and share data with each other.
 
ARPAnet's popularity continued to spread among researchers, and in the 1980's the National Science Foundation, whose NSFNet, linked several high speed computers, took charge of the what had come to be known as the Internet.
 
By the late 1980's, thousands of cooperating networks were participating in the Internet. In 1991, the U.S. High Performance Computing Act established the NREN (National Research & Education Network).
 
NREN's goal was to develop and maintain high-speed networks for research and education, and to investigate commercial uses for the Internet. The rest, as they say, is history in the making.
 
The Internet has been improved through the developments of such services as Gopher and the World Wide Web.
 
Even though the Internet is predominantly thought of as a research oriented network, it continues to grow as an informational, creative, and commercial resource every day and all over the world.
 
Modern computer networking technologies emerged in the early 1970s. In 1969, The U.S. Defense Advanced Research Projects Agency (variously called ARPA and DARPA), an agency within the Department of Defense, commissioned a wide-area computer network called the ARPANET.
 
This network made use of the new packet switching concepts for interconnecting computers and initially linked computers at universities and other research institutions in the United States and in selected NATO countries.
 
At that time, the ARPANET was essentially the only realistic wide-area computer network in existence, with a base of several dozen organizations, perhaps twice that number of computers and numerous researchers at those sites.
 
The program was led at DARPA by Larry Roberts. The packet switches were built by Bolt Beranek and Newman (BBN), a DARPA contractor.
 
Others directly involved in the ARPANET activity included the authors, Len Kleinrock, Frank Heart, Howard Frank, Steve Crocker, Jon Postel and many many others in the ARPA research community.
 
Back then, the methods of internetworking (that is interconnecting computer networks) were primitive or non-existent.
 
Two organizations could interwork technically by agreeing to use common equipment, but not every organization was interested in this approach. Absent that, there was jury-rigging, special case development and not much else.
 
Each of these networks stood on its own with essentially no interaction between them – a far cry from today’s Internet.
 
In the early 1970s, ARPA began to explore two alternative applications of packet switching technology based on the use of synchronous satellites (SATNET) and ground-based packet radio (PRNET).
 
The decision by Kahn to link these two networks and the ARPANET as separate and independent networks resulted in the creation of the Internet program and the subsequent collaboration with Cerf.
 
These two systems differed in significant ways from the ARPANET so as to take advantage of the broadcast and wireless aspects of radio communications.
 
The strategy that had been adopted for SATNET originally was to embed the SATNET software into an ARPANET packet switch, and interwork the two networks through memory-to-memory transfers within the packet switch.
 
This approach, in place at the time, was to make SATNET an “embedded” network within the ARPANET; users of the network would not even need to know of its existence.
 
The technical team at Bolt Beranek and Newman (BBN), having built the ARPANET switches and now building the SATNET software, could easily produce the necessary patches to glue the programs together in the same machine.
 
Indeed, this is what they were under contract with DARPA to provide. By embedding each new network into the ARPANET, a seamless internetworked capability was possible, but with no realistic possibility of unleashing the entrepreneurial networking spirit that has manifest itself in modern day Internet developments. A new approach was in order.
 
The Packet Radio (PRNET) program had not yet gotten underway so there was ample opportunity to change the approach there. In addition, up until then, the SATNET program was only an equipment development activity.
 
No commitments had been obtained for the use of actual satellites or ground stations to access them. Indeed, since there was no domestic satellite industry in the U.S.
 
then, the only two viable alternatives were the use of Intelsat or U.S. military satellites. The time for a change in strategy, if it was to be made, was then.
 
 
 
What was ARPANET?
 
ARPANET stands for Advanced Research Projects Agency (ARPA) Network. The network was developed in 1969 by ARPA and funded by the Department of Defense.
 
The network was chiefly experimental, and was used to research, develop and test networking technologies.
 
The original network connected four host computers at four separate universities throughout the United States, enabling users to share resources and information
 
By 1972, there were 37 host computers connected to ARPANET. Also in this year, ARPA's name was changed to DARPA (Defense Advanced Research Projects Agency).
 
In 1973, ARPANET went beyond the boundaries of the United States by making its first international connections to England and Norway.
 
One goal of ARPANET was to devise a network that would still be operational if part of the network failed. The research in this area resulted in a set of networking rules, or protocols, called TCP/IP (Transmission Control Protocol/Internet Protocol).
 
TCP/IP is a set of protocols that govern how data is transmitted across networks. It also enables different types of computer operating systems, such as DOS and UNIX, to share data across a network.
 
ARPANET functioned as a "backbone" network - allowing smaller local networks to connect to the backbone.
 
Once these smaller networks were connected to the backbone, they were in effect connected to each other.
 
 
In 1983, DARPA decided that TCP/IP would be the standard set of protocols used by computers connecting to ARPANET. This meant that any smaller networks (for example, a university network) that wanted to connect to ARPANET also had to be using TCP/IP.
 
TCP/IP was available for free and was increasingly used by networks. The spread of TCP/IP helped create the Internet as we know it today - the network of networks that either use the TCP/IP protocols, or can interact with TCP/IP networks.
 
 
 
Architecture of Internet
 
The authors created an architecture for interconnecting independent networks that could then be federated into a seamless whole without changing any of the underlying networks. This was the genesis of the Internet as we know it today.
 
In order to work properly, the architecture required a global addressing mechanism (or Internet address) to enable computers on any network to reference and communicate with computers on any other network in the federation.
 
Internet addresses fill essentially the same role as telephone numbers do in telephone networks.
 
The design of the Internet assumed first that the individual networks could not be changed to accommodate new architectural requirements; but this was largely a pragmatic assumption to facilitate progress.
 
The networks also had varying degrees of reliability and speed. Host computers would have to be able to put disordered packets back into the correct order and discard duplicate packets that had been generated along the way.
 
This was a major change from the virtual circuit-like service provided by ARPANET and by then contemporary commercial data networking services such as Tymnet and Telenet.
 
In these networks, the underlying network took responsibility for keeping all information in order and for re-sending any data that might have been lost.
 
The Internet design made the computers responsible for tending to these network problems.
 
A key architectural construct was the introduction of gateways (now called routers) between the networks to handle the disparities such as different data rates, packet sizes, error conditions, and interface specifications.
 
The gateways would also check the destination Internet addresses of each packet to determine the gateway to which it should be forwarded.
 
These functions would be combined with certain end-end functions to produce the reliable communication from source to destination.
 
A draft paper by the authors describing this approach was given at a meeting of the International Network Working Group in 1973 in Sussex, England and the final paper was subsequently published by the Institute for Electrical and Electronics Engineers, the leading professional society for the electrical engineering profession, in its Transactions on Communications in May, 1974 . The paper described the TCP/IP protocol.
 
DARPA contracted with Cerf's group at Stanford to carry out the initial detailed design of the TCP software and, shortly thereafter, with BBN and University College London to build independent implementations of the TCP protocol (as it was then called – it was later split into TCP and IP) for different machines.
 
BBN also had a contract to build a prototype version of the gateway. These three sites collaborated in the development and testing of the initial protocols on different machines.
 
Cerf, then a professor at Stanford, provided the day-to-day leadership in the initial TCP software design and testing. BBN deployed the gateways between the ARPANET and the PRNET and also with SATNET.
 
During this period, under Kahn's overall leadership at DARPA, the initial feasibility of the Internet Architecture was demonstrated.
 
 
The TCP/IP protocol suite was developed and refined over a period of four more years and, in 1980, it was adopted as a standard by the U.S. Department of Defense. On January 1, 1983 the ARPANET converted to TCP/IP as its standard host protocol.
 
Gateways (or routers) were used to pass packets to and from host computers on “local area networks.” Refinement and extension of these protocols and many others associated with them continues to this day by way of the Internet Engineering Task Force
 
 
 
Important Definition
 
Important Definitions of Internet
 
Back/Forward
Buttons in most browsers' Tool Button Bar, upper left. BACK returns you to the document previously viewed. FORWARD goes to the next document, after you go BACK.If it seems like the BACK button does not work, check if you are in a new browser window; some Web pages are programmed to open a new window when you click on some links.
 
Each window has its own short-term search HISTORY. If this does not work, right click on the BACK button to select the page you want (some Web pages are programmed to disable BACK).
 
BLOG or WEB LOG
 
A blog (short for "web log") is a type of web page that serves as a publicly accessible personal journal (or log) for an individual. Typically updated daily, blogs often reflect the personality of the author.
 
Blog software usually has an archive of old blog postings. Many blogs can be searched for terms in the archive.
 
Blogs have become a vibrant, fast-growing medium for communication in professional, poltical, news, trendy, and other specialized web communities. Many blogs provide RSS feeds, to which one can subscribe and receive alerts to new postings in selected blogs.
 
BOOKMARK/FAVORITES
 
Way in browsers to store in your computer direct links to sites you wish to return to. Netscape, Mozilla, and Firefox use the term Bookmarks. The equivalent in Internet Explorer (IE) is called a "Favorite."
 
To create a bookmark, click on BOOKMARKS or FAVORITES, then ADD. Or left-click on and drag the little bookmark icon to the place you want a new bookmark filed. To visit a bookmarked site, click on BOOKMARKS and select the site from the list.
 
You can download a bookmark file to diskette and install it on another computer. In most browsers now, you can do this with an Import... and Export... set of commands which can be found under FILE or in the Manage Bookmarks window's FILE.
 
BOOLEAN LOGIC
 
Way to combine terms using "operators" such as "AND," "OR," "AND NOT" and sometimes "NEAR." AND requires all terms appear in a record. OR retrieves records with either term. AND NOT excludes terms.
 
Parentheses may be used to sequence operations and group words. Always enclose terms joined by OR with parentheses. Which search engines have this?
 
See -REJECT TERM and FUZZY AND. Want a more extensive explanation of Boolean logic, with illustrations?
 
BROWSE
 
To follow links in a page, to shop around in a page, exploring what's there, a bit like window shopping. The opposite of browsing a page is searching it.
 
When you search a page, you find a search box, enter terms, and find all occurrences of the terms throughout the site. When you browse, you have to guess which words on the page pertain to your interests.
 
Searching is usually more efficient, but sometimes you find things by browsing that you might not find because you might not think of the "right" term to search by.
 
BROWSERS
 
Browsers are software programs that enable you to view WWW documents. They "translate" HTML-encoded files into the text, images, sounds, and other features you see.
 
Microsoft Internet Explorer (called simply IE), Mozilla, Firefox, Safari, and Opera are examples of "graphical" browsers that enable you to view text and images and many other WWW features.
 
They are software that must be installed on your computer. For more information about browsers, consult the introductory pages of the Teaching Library tutorial.
 
CACHE
 
In browsers, "cache" is used to identify a space where web pages you have visited are stored in your computer. A copy of documents you retrieve is stored in cache.
 
When you use GO, BACK, or any other means to revisit a document, the browser first checks to see if it is in cache and will retrieve it from there because it is much faster than retrieving it from the server.
 
CACHED LINK
 
In search results from Google, Yahoo! Search, and some other search engines, there is usually a Cached link which allows you to view the version of a page that the search engine has stored in its database.
 
The live page on the web might differ from this cached copy, because the cached copy dates from whenever the search engine's spider last visited the page and detected modified content.
 
Use the cached link to see when a page was last crawled and, in Google, where your terms are and why you got a page when all of your search terms are not in it.
 
CASE SENSITIVE
 
Capital letters (upper case) retrieve only upper case. Most search tools are not case sensitive or only respond to initial capitals, as in proper names. It is always safe to key all lower case (no capitals), because lower case will always retrieve upper case. Which search engines have this?
 
CGI
 
"Common Gateway Interface," the most common way Web programs interact dynamically with users.
 
. Many search boxes and other applications that result in a page with content tailored to the user's search terms rely on CGI to process the data once it's submitted, to pass it to a background program in JAVA, JAVASCRIPT, or another programming language, and then to integrate the response into a display using HTML.
 
COOKIE
 
A message from a WEB SERVER computer, sent to and stored by your browser on your computer. When your computer consults the originating server computer, the cookie is sent back to the server, allowing it to respond to you according to the cookie's contents.
 
The main use for cookies is to provide customized Web pages according to a profile of your interests. When you log onto a "customize" type of invitation on a Web page and fill in your name and other information, this may result in a cookie on your computer which that Web page will access to appear to "know" you and provide what you want.
 
If you fill out these forms, you may also receive e-mail and other solicitation independent of cookies.  
 
DOMAIN, TOP LEVEL DOMAIN (TLD)
 
Hierarchical scheme for indicating logical and sometimes geographical venue of a web-page from the network. In the US, common domains are .edu (education), .gov (government agency), .net (network related), .com (commercial), .org (nonprofit and research organizations).
 
Outside the US, domains indicate country: ca (Canada), uk (United Kingdom), au (Australia), jp (Japan), fr (France), etc. Neither of these lists is exhaustive. See also DNS entry.
 
DOMAIN NAME, DOMAIN NAME SERVER (DNS)ENTRY
 
Any of these terms refers to the initial part of a URL, down to the first /, where the domain and name of the host or SERVER computer are listed (most often in reversed order, name first, then domain).
 
The domain name gives you who "published" a page, made it public by putting it on the Web.
 
A domain name is translated in huge tables standardized across the Internet into a numeric IP address unique the host computer sought. These tables are maintained on computers called "Domain Name Servers.";
 
Whenever you ask the browser to find a URL, the browser must consult the table on the domain name server that particular computer is networked to consult.
 
"Domain Name Server entry" frequently appears a browser error message when you try to enter a URL. If this lookup fails for any reason, the "lacks DNS entry" error occurs.
 
The most common remedy is simply to try the URL again, when the domain name server is less busy, and it will find the entry (the corresponding numeric IP address). For more information, see "All About Domain Names."
 
Download
 
To copy something from a primary source to a more peripheral one, as in saving something found on the Web (currently located on its server) to diskette or to a file on your local hard drive. More information.
 

EXTENSION or FILE EXTENSION

 
In Windows, DOS and some other operating systems, one or several letters at the end of a filename. Filename extensions usually follow a period (dot) and indicate the type of file.
 
For example, this.txt denotes a plain text file, that.htm or that.html denotes an HTML file. Some common image extensions are picture.jpg or picture.jpeg or picture.bmp or picture.gif
 
FAVORITES
 
In the Internet Explorer browser, a means to get back to a URL you like, similar to Bookmarks.
 
FEED READER
 
A software package that enables you to easily read the XML code in which RSS feeds are written. Bloglines is currently the most popular feed reader but there are many competitors.
 
FIND
 
Tool in most browsers to search for word(s) keyed in document in screen only. Useful to locate a term in a long document. Can be invoked by the keyboard command, Ctrl+F.
 
FRESHNESS
 
How up-to-date a search engine database is, based primarily on how often its spiders recirculate around the Web and update their copies of the web pages they hold, and discover new ones.
 
Also determined by how quickly they integrate new sites that web authors send to them. Two weeks is about as good as most search engines do, but some update certain selected web sites more frequently, even daily.
 
FRAMES
 
A format for web documents that divides the screen into segments, each with a scroll bar as if it were as "window" within the window.
 
Usually, selecting a category of documents in one frame shows the contents of the category in another frame. To go BACK in a frame, position the cursor in the frame an press the right mouse button, and select "Back in frame" (or Forward).
 
You can adjust frame dimensions by positioning the cursor over the border between frames and dragging the border up/down or right/left holding the mouse button down over the border
 
FTP
 
File Transfer Protocol. Ability to transfer rapidly entire files from one computer to another, intact for viewing or other purposes.
 
FUZZY AND
 

In ranking of results, documents with all terms (Boolean AND) are ranked first, followed by documents containing any terms (Boolean OR) are retrieved. The farther down, the fewer the terms, although at least one should always be present.

 
HEAD or HEADER
 
The top portion of the HTML source code behind Web pages, beginning with <HEAD> and ending with . It contains the Title, Description, Keywords fields and others that web page authors may use to describe the page.
 
The title appears in the title bar of most browsers, but the other fields cannot be seen as part of the body of the page. To view the <HEAD> portion of web pages in your browser, click VIEW, Page Source. In Internet Explorer, click VIEW, Source. Some search engines will retrieve based on text in these fields.
 
HISTORY, Search History
 
Available by using the combined keystrokes CTRL + H, a more permanent record of sites you have visited/retrieved than GO. You can set how many days your browser retains history in Edit | Preferences, or in Tools | Options.
 
HOST
 
Computer that provides web-documents to clients or users. See also server.
 
HTML
 
On the World Wide Web, the feature, built into HTML, that allows a text area, image, or other object to become a "link" (as if in a chain) that retrieves another computer file (another Web page, image, sound file, or other document) on the Internet.
 
The range of possibilities is limited by the ability of the computer retrieving the outside file to view, play, or otherwise open the incoming file.
 
It needs to have software that can interact with the imported file. Many software capabilities of this type are built into browsers or can be added as "plug-ins."
 
INTERNET
 
The vast collection of interconnected networks that all use the TCP/IP protocols and that evolved from the ARPANET of the late 60’s and early 70’s. An "internet" (lower case i) is any computers connected to each other (a network), and are not part of the Internet unless the use TCP/IP protocols.
 
An "intranet" is a private network inside a company or organization that uses the same kinds of software that you would find on the public Internet, but that is only for internal use. An intranet may be on the Internet or may simply be a network.
 
IP Address or IP Number
 
(Internet Protocol number or address). A unique number consisting of 4 parts separated by dots, e.g. 165.113.245.2 Every machine that is on the Internet has a unique IP address.
 
If a machine does not have an IP number, it is not really on the Internet. Most machines also have one or more Domain Names that are easier for people to remember.
 
Internet Service Provider
 
A company that sells Internet connections via modem (examples: aol, Mindspring - thousands of ISPs to choose from; not easy to evaluate).
 
Faster, more expensive Internet connectivity is available via cable, DSL, ISDN, or web-TV. Often these companies also provide Web page hosting service (free or relatively inexpensive web pages -- the origin of many personal pages).
 
JAVA
 
A network-oriented programming language invented by Sun Microsystems that is specifically designed for writing programs that can be safely downloaded to your computer through the Internet and immediately run without fear of viruses or other harm to our computer or files.
 
Using small Java programs (called "Applets"), Web pages can include functions such as animations, calculators, and other fancy tricks.
 
We can expect to see a huge variety of features added to the Web using Java, since you can write a Java program to do almost anything a regular computer program can do, and then include that Java program in a Web page.
 
For more information search any of these jargon terms in the PC Webopedia.
 
JAVASCRIPT
 
A simple programming language developed by Netscape to enable greater interactivity in Web pages. It shares some characteristics with JAVA but is independent. It interacts with HTML, enabling dynamic content and motion.
 
KEYWORD(S)
 
A word searched for in a search command. Keywords are searched in any order. Use spaces to separate keywords in simple keyword searching. To search keywords exactly as keyed (in the same order), see PHRASE.
 
LINK
 
The URL imbedded in another document, so that if you click on the highlighted text or button referring to the link, you retrieve the outside URL.
 
If you search the field "link:", you retrieve on text in these imbedded URLs which you do not see in the documents.
 
LINK "ROT"
 
Term used to describe the frustrating and frequent problem caused by the constant changing in URLs. A Web page or search tool offers a link and when you click on it, you get an error message (e.g., "not available") or a page saying the site has moved to a new URL.
 
Search engine spiders cannot keep up with the changes. URLs change frequently because the documents are moved to new computers, the file structure on the computer is reorganized, or sites are discontinued.
 
If there is no referring link to the new URL, there is little you can do but try to search for the same or an equivalent site from scratch.
 
META-SEARCH ENGINE
 
Search engines that automatically submit your keyword search to several other search tools, and retrieve results from all their databases.
 
Convenient time-savers for relatively simple keyword searches (one or two keywords or phrases in " "). See Meta-Search Engines page for complete descriptions and examples.
 
NESTING
 
A term used in Boolean searching to indicate the sequence in which operations are to be performed. Enclosing words in parentheses identifies a group or "nest." Groups can be within other groups. The operations will be performed from the innermost nest to the outmost, and then from left to right.
 
NEWSGROUP
 
A discussion group operated through the Internet. Not to be confused with LISTSERVERS which operate through e-mail.
 
PERSONAL PAGE
 
A web page created by an individual (as opposed to someone creating a page for an institution, business, organization, or other entity). Often personal pages contain valid and useful opinions, links to important resources, and significant facts.
 
One of the greatest benefits of the Web is the freedom it as given almost anyone to put his or her ideas "out there." But frequently personal pages offer highly biased personal perspectives or ironical/satirical spoofs, which must be evaluated carefully.
 
The presence in the page's URL of a personal name (such as "jbarker") and a ~ or % or the word "users" or "people" or "members" very frequently indicate a site offering personal pages.
 
PACKET, PACKET JAM
 
When you retrieve a document via the WWW, the document is sent in "packets" which fit in between other messages on the telecommunications lines, and then are reassembled when they arrive at your end.
 
This occurs using TCP/IP protocol. The packets may be sent via different paths on the networks which carry the Internet. If any of these packets gets delayed, your document cannot be reassembled and displayed.
 
This is called a "packet jam." You can often resolve packet jams by pressing STOP then RELOAD. RELOAD requests a fresh copy of the document, and it is likely to be sent without jamming.
 
PDF or .pdf or pdf file
 
Abbreviation for Portable Document Format, a file format developed by Adobe Systems, that is used to capture almost any kind of document with the formatting in the original. Viewing a PDF file requires Acrobat Reader, which is built into most browsers and can be downloaded free from Adobe.
 
PLUG-IN
 
An application built into a browser or added to a browser to enable it to interact with a special file type (such as a movie, sound file, Word document, etc.)
 
POPULARITY RANKING of search results
 
Some search engines rank the order in which search results appear primarily by how many other sites link to each page (a kind of popularity vote based on the assumption that other pages would create a link to the "best" pages). Google is the best example of this. See also Subject-Based Ranking.
 
+REQUIRE or -REJECT A TERM OR PHRASE
 
Insert + immediately before a term (no space) to limit search to documents containing a term. Insert - immediately before a term (no space) to exclude documents containing a term. Can be used immediately (no space) before the " " delimiting a phrase.
 
Functions partially like basic BOOLEAN LOGIC. If + precedes more than one term, they are required as with Boolean AND. If - is used, terms are excluded as with Boolean AND NOT. If neither + no - is used, the default if Boolean OR.
 
However, full Boolean logic allows parentheses to group and sequence logical operations, and +/- do not. Which search engines have this?
 
RELEVANCY RANKING of search results
 
The most common method for determining the order in which search results are displayed. Each search tool uses its own unique algorithm.
 
Most use "fuzzy and" combined with factors such as how often your terms occur in documents, whether they occur together as a phrase, and whether they are in title or how near the top of the text. Popularity is another ranking system.
 
SCRIPT
 
A script is a type of programming language that can be used to fetch and display Web pages. There are may kinds and uses of scripts on the Web. They can be used to create all or part of a page, and communicate with searchable databases.
 
Forms (boxes) and many interactive links, which respond differently depending on what you enter, all require some kind of script language. When you find a question marke (?) in the URL of a page, some kind of script command was used in generating and/or delivering that page.
 
Most search engine spiders are instructed not to crawl pages from scripts, although it is usually technically possible for them to do so (see Invisible Web for more information).
 
SERVER, WEB SERVER
 
A computer running that software, assigned an IP address, and connected to the Internet so that it can provide documents via the World Wide Web. Also called HOST computer. Web servers are the closest equivalent to what in the print world is called the "publisher" of a print document.
 
An important difference is that most print publishers carefully edit the content and quality of their publications in an effort to market them and future publications.
 
This convention is not required in the Web world, where anyone can be a publisher; careful evaluation of Web pages is therefore mandatory. Also called a "Host."
 
SERVER-SIDE
 
Something that operates on the "server" computer (providing the Web page), as opposed to the "client" computer (which is you or someone else viewing the Web page). Usually it is a program or command or procedure or other application causes dynamic pages or animation or other interaction.
 
SITE or WEB-SITE
 
This term is often used to mean "web page," but there is supposed to be a difference. A web page is a single entity, one URL, one file that you might find on the Web.
 
A "site," properly speaking, is an location or gathering or center for a bunch of related pages linked to from that site. For example, the site for the present tutorial is the top-level page "Internet Resources."
 
All of the pages associated with it branch out from there -- the web searching tutorial and all its pages, and more. Together they make up a "site." When we estimate there are 5 billion web pages on the Web, we do not mean "sites." There would be far fewer sites.
 
SPIDERS
 
Computer robot programs, referred to sometimes as "crawlers" or "knowledge-bots" or "knowbots" that are used by search engines to roam the World Wide Web via the Internet, visit sites and databases, and keep the search engine database of web pages up to date.
 
They obtain new pages, update known pages, and delete obsolete ones. Their findings are then integrated into the "home" database.
 
Most large search engines operate several robots all the time. Even so, the Web is so enormous that it can take six months for spiders to cover it, resulting in a certain degree of "out-of-datedness" (link rot) in all the search engines. For more information, read about search engines.
 
SPONSOR
 
Many Web pages have organizations, businesses, institutions like universities or nonprofit foundations, or other interests which "sponsor" the page. Frequently you can find a link titled "Sponsors" or an "About us" link explaining who or what (if anyone) is sponsoring the page.
 
Sometimes the advertisers on the page (banner ads, links, buttons to sites that sell or promote something) are "sponsors." WHY is this important? Sponsors and the funding they provide may, or may not, influence what can be said on the page or site -- can bias what you find, by excluding some opposing viewpoint or causing some other imbalanced information.
 
The site is not bad because of sponsors, but you they should alert you to the need to evaluate a page or site very carefully.
 
SSI commands
 
SSI stands for "server-side include," a type of HTML instruction telling a computer that serves Web pages to dynamically generate data, usually by inserting certain variable contents into a fixed template or boilerplate Web page. Used especially in database searches.
 
SUBJECT-BASED POPULARITY RANKING of search results
 
A variation on popularity ranking in which the links in pages on the same subject are used to in ranking search results. Used by Teoma.
 
SUBJECT DIRECTORY
 
An approach to Web documents by a lexicon of subject terms hierarchically grouped. May be browsed or searched by keywords. Subject directories are smaller than other searchable databases, because of the human involvement required to classify documents by subject.
 
SUB-SEARCHING
 
Ability to search only within the results of a previous search. Enables you to refine search results, in effect making the computer "read" the search results for you selecting documents with terms you sub-search on. Can function much like RESULTS RANKING. Which search engines have this?
 
TCP/IP
 
(Transmission Control Protocol/Internet Protocol) -- This is the suite of protocols that defines the Internet. Originally designed for the UNIX operating system, TCP/IP software is now available for every major kind of computer operating system. To be truly on the Internet, your computer must have TCP/IP software. See also IP Address.
 
TELNET ;
 
Internet service allowing one computer to log onto another, connecting as if not remote.
 
THESAURUS
 
In some search tools, the terms you choose to search on can lead you to other terms you may not have thought of. Different search tools have different ways of presenting this information, sometimes with suggested words you may choose among and sometimes automatically. The terms are based on the terms in the results of your search, not on some dictionary-like thesaurus.
 
TITLE (of a document)
 
The official title of a document from the "meta" field called title. The text of this meta title field may or may not also occur in the visible body of the document.
 
It is what appears in the top bar of the window when you display the document and it is the title that appears in search engine results. The "meta" field called title is not mandatory in HTML coding. Sometimes you retrieve a document with "No Title" as its supposed title; this is caused when the meta-title field is left blank.
 
In Alta Vista and some other search tools, title: search also matches on the "meta" field, which contains document descriptors not displayed on the Web. See also LIMITING TO A FIELD.
 
URL
 
Uniform Resource Locator. The unique address of any Web document. May be keyed in a browser's OPEN or LOCATION / GO TO box to retrieve a document. There is a logic the layout of a URL:
 
Type of file (could say ftp:// or telnet://) Domain name (computer file is on and its location on the Internet) Path or directory on the computer to this file Name of file, and its file extension (usually ending in .html or .htm)
http:// www.lib.berkeley.edu/ TeachingLib/Guides/Internet FindInfo.html
 
USENET
 
Bulletinboard-like network featuring thousands of "newsgroups." Google incorporates the historic file of Usenet Newsgroups (bzck to 1981) into its Google Groups. Yahoo Groups offers a similar service, but does not include the old "Usenet Newsgroups." Blogs are replacing some of the need for this type of community sharing and information exchange.
 
WORD VARIANTS
 
Different word endings (such as -ing, -s, es, -ism, -ist,etc.) will be retrieved only if you allow for them in your search terms. One way to do this TRUNCATION, but few systems accept truncation.
 
Another way is to enter the variants either separated by BOOLEAN OR (and grouped in parentheses). In +REQUIRE/-REJECT non-Boolean systems, enter the variant terms preceded with neither + nor -, because this will allow documents containing any of them to retrieved.
 
XHTML
 
A variant of HTML. Stands for Extensible Hypertext Markup Language is a hybrid between HTML and XML that is more universally acceptable in Web pages and search engines than XML.
 
XML
 
Extensible Markup Language, a dilution for Web page use of SGML (Standard General Markup Language), which is not readily viewable in ordinary browsers and is difficult to apply to Web pages.
 
XML is very useful (among other things) for pages emerging from databases and other applications where parts of the page are standardized and must reappear many times. See XHTML.
 
 
 
Components of Internet
 
WEB Browsers
 
Web Browser
 
Web Browsers are the programs that work as an interface between the World Wide Web’s technology and user. Web Browser is software that enables user to display and interact with the information which is located on a web page at a website on World Wide Web or local area network.
These are also available for personal computer. Internet Explorer, Mozilla Firefox, Safari, Netscape and Opera are the popular browsers. Web Browsers are the most commonly types of HTTP user agents. Web Browers may be different from each others by the features they support.
 
It may be Text Based browser or Graphical browser. It makes the Internet more intuitive to use. There are many different types of browsers. In Text Based browser, user can only see the texts but a Graphical browser allows user to see the images, sounds, multimedia and that things what WWW facilitate.
 
This is Netscape browser.
 
 
Elements of Web Browser
 
Now, you are well-known of Web Browser. Here, we will discuss about the most important aspect of Web Browser.
 
There are important features of the Internet have given bellow:
 
Hyperlinks:
 
This is the most navigational element of the Web Browser. Links are the pieces of text which takes you to another page or somewhere else within the same page.
 
For an example: This is the link for www.mkmovietrailer.blogspot.com.
 
You can differentiate the visited link and the links which have not been visited yet. It has different color before visiting and after visiting. Such as, the above link has not been clicked or visited yet. But the link that is given bellow has been visited. So, also it has different color.
 
This is the link for http://mkmovietrailer.blogspot.com.
 
Location/ Address Box:
 
This is another way to go to the particular website. Through this way, you only need to type the URL (Universal Location Register) in the address box and press the Go button/ “Enter” key.
 
Back Button:
 
It is also an important button like other features in web browser. By clicking this button, you can navigate your last visited page in the same web browser.
 
Go Menu:
 
The Go menu has a list of all the pages you have visited. You can use the links from the list to get back to a page you have previously visited. It saves you having to repeatedly press the back button. In Netscape, use the "Go" menu on the menu bar. In Internet Explorer the menu is on the down arrow next to the Back button.
 
Bookmarks/ Favorites:
 
This is a place holder of web page. At the time of browsing, if you want to visit that page again in future then you can add it in Bookmarks or in Favorites.
 
So, in feature, if you would like to open that page again then simply go to Favorites and click on that link. It will open that web page. For your assistance, you can also make the folder in Favorites or in Bookmarks and add in that particular folder.
 
Images:
 
Images are the part of the pages which make web pages more interactive. But it also makes slow to load the web page. So, if you want to download the images then simply click the right mouse button on that image and click on “Save Picture As” option.
 
Home Button:
 
This button takes you back to “Home” page. You can define your home page from the Internet Option/ Browser’s Preference. You can give the address of most useful website or the website that you visit most
 
Reload/ Refresh:
 
This is very useful feature of the web browser. This button loads the whole web page again. It is useful when;
 
1) Parts of page are missing at the time of loading due to any reason.
 
2) You are browsing that web page which gets changes in its contents often and you want to view the new contents.
 
New Browser Window:
 
It is useful when you want to open the link page in new browser window. Sometime you want to keep the main page open and also want to view the link page. In that condition, you can opt for this option. To open new browser window, simply click the right mouse button on the link and choose “Open Link in New Window” option.
 
Downloading Files:
 
Sometime, you might want to get the file from the web and save it to your computer. It is easy to save that file in your computer. For that you need to:
 
1) Click the right mouse button on the link.
2) Choose the “Save Link As” / “Save Target As” option.
3) After choosing this option, a file window will come up. From this window, choose the location on your computer where you want to save the file.
4) Click OK button to start the downloading process.
5) A “Saving Location” dialogue box will come up and show you that how much time the downloading process will take.
 
You may find the links where a single click can download the file for you. There may appear a dialogue box and you may be asked whether you want to save, run or cancel.
Note: If you have downloaded the file then first scan it for virus before run them.
 
Zip Files:
 
Zipping is the act of packaging a set of files into a single file or archive that is called a zip file. Usually, the files in a zip file are compressed so that they take up less space in storage or take less time to send to someone. There are several popular tools that can be used for zipping files: PKZIP for the DOS operating system, WinZip and Netzip for Windows, MacZip for Macintosh users, and Zip and UnZip for UNIX systems. The result of zipping is a single file with a ".zip" suffix.

WinZip logo
 
 
Files/ Folders are being compressed to make the file/ folder size smaller to make them quicker to download. After you have downloaded the file, you need to unzip it using special software to open the file. If you have such software installed in your computer then you can simply open the file on double click. There is an icon of zip folder bellow:
 
 
Forms:
 
Form is part of the web page into which you can enter information by typing in the text box, choosing an option by clicking a menu and clicking a checkbox.
 
The following elements can make up the user-inputting portion of a form:
 
• input field
 
o text – a simple text box that allows input of a single line of text
o checkbox – a check box o radio – a radio button
o submit – a button that tells the browser to take action on the form (typically to send it to a server)
 
text area – much like the text input field except a text area allows for multiple rows of data to be shown and entered
 
select – a drop-down list that displays a list of items a user can select from
 
Forms can be combined with various scripting languages to allow developers to create dynamic web sites. This includes both client-side and/or server-side languages.
 
There is an example of form:-
 
 
 
 
WWW
 
The World Wide Web is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. The World Wide Web is often abbreviated as the Web or WWW.The World Wide Web was developed in 1989 by Tim Berners-Lee of the European Particle Physics Lab (CERN) in Switzerland.
 
The initial purpose of the Web was to use networked hypertext to facilitate communication among its members, who were located in several countries.
 
Word was soon spread beyond CERN, and a rapid growth in the number of both developers and users ensued. In addition to hypertext, the Web began to incorporate graphics, video, and sound.
 
The use of the Web has reached global proportions and has become a defining aspect of human culture in an amazingly short period of time.
 
Almost every protocol type available on the Internet is accessible on the Web. Internet protocols are sets of rules that allow for intermachine communication on the Internet.
The following is a sample of major protocols accessible on the Web:
 
E-mail (Simple Mail Transport Protocol or SMTP) Distributes electronic messages and files to one or more electronic mailboxes
 
Telnet (Telnet Protocol) Facilitates login to a computer host to execute commands
 
FTP (File Transfer Protocol) Transfers text or binary files between an FTP server and client
 
Usenet (Network News Transfer Protocol or NNTP) Distributes Usenet news articles derived from topical discussions on newsgroups
 
HTTP (HyperText Transfer Protocol) Transmits hyptertext over networks. This is the protocol of the Web.
 
Many other protocols are available on the Web. To name just one example, the Voice over Internet Protocol (VoIP) allows users to place a telephone call over the Web.
 
The World Wide Web provides a single interface for accessing all these protocols. This creates a convenient and user-friendly environment. Once upon a time, it was necessary to be conversant in these protocols within separate, command-level environments.
 
The Web gathers these protocols together into a single system. Because of this feature, and because of the Web's ability to work with multimedia and advanced programming languages, the Web is by far the most popular component of the Internet.
 
• A way to provide and access information resources on the Internet
 
Based on hypertext and HTTP (Hypertext Transfer Protocol)
Non-linear
Multimedia
Flexible
 
The World Wide Web, also referred to as the WWW and "the Web," is the universe of information available via hypertext transfer protocol (HTTP).
 
The World Wide Web and HTTP:
 
• Allow you to create "links" from one piece of information to another; can incorporate references to sounds, graphics, and movies, etc.; "understand" other Internet protocols, such as ftp, gopher, and telnet.
 
• The Web presents information as a series of "documents," often referred to as web pages, that are prepared using the Hypertext Markup Language (HTML).
 
Using HTML, the document's author can specially code sections of the document to "point" to other information resources. These specially coded sections are referred to as hypertext links.
 
Users viewing the webpage can select the hypertext link and retrieve or connect to the information resource that the link points to.
 
Hypertext "links" can lead to other documents, sounds, images, databases (like library catalogs), e-mail addresses, etc. This sample web page is from the Smithsonian:
 
Screen shot of a 

Smithsonian webpage with  images, sound clips and text
 
Because it can incorporate graphics and "understands" other Internet protocols, the web can provide an easy-to-use interface for resources available via these protocols.
 
Diagram of web page 

showing links to a  library catalog via telnet, to a gopher site and to an FTP site
 
• The World Wide Web is non-linear. There is no top, there is no bottom. Non-linear means you do not have to follow a hierarchical path to information resources.
 
You can jump from one link (resource) to another:
 
Diagram showing links 

from one resource  to a second resource to a third resource
 
You can go directly to a resource if you know the Uniform Resource Locator (URL) (its address):
 
Diagram showing link from one resource  

directly to a second resource
 
You can even jump to specific parts of a document.
 
Because the Web is not hierarchical and can handle graphics, it offers a great deal of flexibility in the way information resources can be organized, presented, and described.
 
Two screen shots showing image 

maps
 
The World Wide Web is a system, based on hypertext and HTTP, for providing, organizing, and accessing a wide variety of resources (text, images, sound) that are available via the Internet.
 
The advantages of the Web are its flexibility in organizing and presenting information, its non-hierarchical easy-to-navigate structure, its ability to handle and "understand" many different file formats and Internet protocols, and its overall ease of use
 
 
 
Web Pages
 
Unit of information
 
HTML (Hypertext Markup Language)
 
Text file
 
HTTP (Hypertext Transfer Protocol)
 
A web page is a single unit of information, often called a document, that is available via the World Wide Web (WWW). A web page can be longer than one computer screen and can use more than one piece of paper when it is printed out. A web page is created using Hypertext Markup Language (HTML).
 
HTMLconsists of standardized codes, or tags, that are used to define the structure of a web page. These codes enable web pages to have many features including bold text, italic text, headings, paragraph breaks and numbered or bulleted lists.
 
Web pages can contain text, images, sound files, video files and hypertext links to other Internet resources. All of these features are indicated by using HTML codes.
 
The following web page was created with the HTML coding shown. On the left is the HTML file that was written to create the web page. The HTML file is a plain text file that has been saved with an ".html" file extension. HTML files can be written in any text editing program.
 
[Graphic of web page that results from 

the HTML source code at left.]
 
Following is a screen shot of the Library of Congress, "American Memory" web page, showing links to movies, sound recordings and photos.
 
[Screen shot of web page]
 
A web page is transferred to a user's computer via the hypertext transfer protocol (HTTP). HTTP is the method through which hypertext files, such as web pages, are transferred over the Internet. HTTP is a client/server based Internet protocol, or set of rules.
 
Web pages generally reside on HTTP servers. A user requests a web page from an HTTP (web) server through his or her web browser client software, either by clicking on a hypertext link or designating a particular URL (Uniform Resource Locator). The server then sends the requested information to the user's computer.
 
The browser software interprets the HTML codes and presents the information contained in the web page in a readable format on the user's computer.
 
A web page is a unit of information, often called a document, that is available over the World Wide Web. Web pages are created using HTML which defines the contents of a web page such as images, text, hypertext links, video and audio files, etc. HTML files are text files that have been saved with an ".html" file extension.
 
Web pages are sent and received through HTTP, a client/server based method used to transfer hypertext files across the Internet. Browser client software enables users to request web pages from an HTTP (web) server, and to view the requested web pages on their computer screen.
 
 
 
Website
 
A web site is a collection of related Web pages with a common Web address. An analogy would be to a house with different rooms. It can also be useful to view a web site as a "virtual city" where the domain name is the center square, the folders in URL's are streets, and the pages are buildings.
 
Some buildings are closer to the centre square than others, and some are connected to other buildings elsewhere in the city by side streets, tunnels, and alleyways -- i.e., links.
 
Information on the Web is displayed in pages (files). The New York Times and CBS are examples of two organizations that have web sites.
 
The New York Times web site, for example, would include the newspaper itself, archived articles from the newspaper and other related information about the company and its many products.
 
Most pages on the web are written in a standard markup language called HTML (HyperText Markup Language) and JavaScript. These languages describes how information should be displayed regardless of the browser used or the type of computer.
 
Pages also include hypertext links which allow users to jump to other related information. Hypertext is usually underlined and in a different color (but not always) and can include individual words, sentences, or even graphics
 
 
 
HTML
 
HTML stands for Hypertext Markup Language. HTML consists of standardized codes,or "tags", that are used to define the structure of information on a web page. HTML is used to prepare documents for the World Wide Web. A web page is single a unit of information, often called a document, that is available on the World Wide Web. HTML defines several aspects of a web page including heading levels, bold, italics, images, paragraph breaks and hypertext links to other resources .
 
HTML can be compared to word processing. The text in a word processed file can be formatted in various ways. For example, a heading can be bold and in larger font size than the rest of the document. Also, specific words can be italicized for emphasis.
 
HTML is a way to define the formats of text in a web page. However, it goes further by also being able to define placement of graphics and hypertext links.
 
HTML is a sub-language of SGML, or Standard Generalized Markup Language. SGML is a system that defines and standardizes the structure of documents.
 
Both SGML and HTML utilize descriptive markup to define the structure of an area of text. In general terms, descriptive markup does not specify a particular font or point size for an area of text. Instead, it describes an area of text as a heading or a caption, for example.
 
Therefore, in HTML, text is marked as a heading, subheading, numbered list, bold, italic, etc
 
HTML is standardized and portable. A document that has been prepared using HTML markup "tags" can be viewed using a variety of web browsers, such as Netscape and Lynx. A browser interprets the tags in an HTML file and presents the file as a formatted, readable web page.
 
In addition, HTML documents can be viewed on all types of systems, such as Macintosh, PC and UNIX machines. HTML tags are used to define areas of a document as having certain characteristics.
 
The tags used in HTML usually consist of a code in between two "wickets". These codes are called container tags because the formatting described by the tags affects only the text contained between the tags.
 
For example,<B >and </B>are the starting and ending tags used to indicate an area as bold. Therefore, the following markup will yield a sentence with the word "hello" in bold.
 
Only the word<B>Hello</B>will be bold.
 
HTML tags are used to define heading levels, such as<H1> and</H2> . Heading levels can go to <H6>
, with each successive number indicating a smaller heading size.
 
Some other basic HTML tags are:
 
<I>and</I> used to indicate italics
• <img src="name of picture">used to place an image in a document file
•<P> used to create a paragraph break
 
The following HTML markup produces the web page shown.
 
On the left is the HTML file that was written to create the web page. The HTML file is a plain text file that has been saved with an ".html" file extension. HTML files can be written in any text editing program.
 
HTML, some codes require end tags and some do not require end tags.
 
In the previous example, the<P> tags indicate a paragraph break. This type of code is called an empty tag because no end tag is required.
The<P> tag does not need an end tag (like<B> and</B> ) because a paragraph break is a single entity.
 
HTML is a set of standardized codes, or tags, that have been derived from the SGML standard. HTML defines and describes the structure of a web page and is used to prepare documents for the World Wide Web. In addition, HTML documents are portable - they can be viewed with any web browser on any type of computer.
 
The tags used in HTML consist of a code in between two "wickets". For example, For example,<I> and</I> are the starting and ending tags used to indicate an area of text as italic. Some tags, such the paragraph break,<P>do not require an ending tag.
 
 
 
HTTP
 
HTTP is an acronym for Hypertext Transfer Protocol. HTTP is the set of rules, or protocol, that enables hypertext data to be transferred from one computer to another, and is based on the client/server principle. Hypertext is text that is coded using the Hypertext Markup Language. These codes and HTTP work together to link resources to each other. HTTP enables users to retrieve a wide variety of resources such as text, graphics,
 
• Protocol
Client/Server based
Hypertext, graphics, animation, sound
Access to other protocols
 
HTTP is short for Hypertext Transfer Protocol. It is the set of rules, or protocol, that governs the transfer of hypertext between two or more computers.
 
The World Wide Web encompasses the universe of information that is available via HTTP.
 
So what is hypertext?
 
Hypertext is text that is specially coded using a standard system called Hypertext Markup Language (HTML).
 
The HTML codes are used to create links. These links can be textual or graphic, and when clicked on, can "link" the user to another resource such as other HTML documents, text files, graphics, animation and sound.
 
HTTP is based on the client/server principle.
 
HTTP allows "computer A" (the client) to establish a connection to "computer B" (the server) and make a request. The server accepts the connection initiated by the client and sends back a response.
 
An HTTP request identifies the resource that the client is interested in and tells the server what "action" to take on the resource.
 
When a user selects a hypertext link, the client program on their computer uses HTTP to contact the server, identify a resource, and ask the server to respond with an action. The server accepts the request, and then uses HTTP to respond to or perform the action.
 
For example, when you select any of the following underlined hypertext links, you are identifying a particular resource, and asking the server to send it back to your computer in a format that your computer can display.
 
HTTP also provides access to other Internet protocols, among them:
 
• File Transfer Protocol (FTP)
• Simple Mail Transfer Protocol (SMTP)
• Network News Transfer Protocol (NNTP)
• WAIS
• gopher
• Telnet and TN3270
 
sound, animation and other hypertext documents, and allows hypertext access to other Internet protocols.
 
 
 
URL
 
All of the documents that you will find on the Internet are differentiated by a unique address which is technically referred to as a URL which stands for Uniform Resource Locator.
 
Think of it as a networked extension of the standard filename concept: not only can you point to a file in a directory, but that file and that directory can exist on any machine on the network, and can be served via a several different methods.
 
They can look complicated but are easier to understand when you divide it into its component parts. Understanding how URL's are composed will enable you to locate and remember document locations with greater ease.
 
The first part http:// indicates that you wish to retrieve a document via the world wide web and stands for HypterText Transfer Protocol.
 
Most resources that you will access are located on World Wide Web servers and are thus named www at the beginning of the address. Each world wide web server will have a domain name. This is the domain name for SOFWeb - sofweb.vic.edu.au.
 
Web pages can be organised into directories. This web page sits in a directory called internet. Lastly each web page has its own file name - this document is called intro.htm. All web pages end in .htm or html because they are documents prepared for viewing on the web through a web browser.
 
To access a URL you only need to click on the Open Location button on your browser and type in the URL and press enter. All URL's or Web pages that you visit can be saved into your bookmarks file in your browser so that you don't have to remember them all.
 
Sometimes you may come across a url that starts with ftp:// instead of http:// this means that the file is located on an FTP server instead of a WWW server. FTP servers are sometimes used for downloading files as they are a lot quicker than the standard WWW server.
 
When you are accessing Newsgroups the urls will always start with news. eg. news:rec.gardening.
URL stands for Uniform Resource Locator. URLs are used to identify specific sites and files available on the World Wide Web.
 
The structure of a URL is: protocol://server.subdomain.top-level-domain/directory/filename Not all URLs will have the directory and filename.
 
Two examples:
 
http://www.downloadkabaap.blogspot.in/2013/05/online-shopping.html
 
gopher://gopher.state.edu/
 
URLs
 
Similar to an e-mail address, a URL is read like a sentence.
For example the URL http://www.downloadkabaap.blogspot.com/ is read as "http colon forward slash forward slash www dot healthyway dot com".
Internet addressing is used to identify people, computers, and Internet resources.
 
Using the Internet requires an understanding of different addressing schemes. People are identified with electronic mail addresses. Computers are identified with IP addresses and domain names. Resources and files available through the World Wide Web are identified using URLs.
 
 
 
Gopher
 
Gopher is a client/server system that allows you to access many Internet resources simply by making selections from a sequence of menus. Each time you make a selection, Gopher carries out your request to the computer that contains the information and "serves" it up.
 
For example, if you select a menu item that represents a text file, Gopher will get that file--wherever it happens to be--and display it for you. As you use Gopher, some menu items lead to other menus. If you choose one of these, Gopher will retrieve the new menu and display it for you.
 
Thus you can move from menu to menu, using only a few key strokes or a mouse to navigate. The power of Gopher is that the resources listed in a menu may be anywhere on the Internet.
 
As Gopher connects to computers to comply with your menu selection, you don't need to be preoccupied with the behind-the-scenes work of connecting to and disconnecting from these various computers. Gopher does this for you without your even needing to be aware of it. This automatic connecting makes Gopher popular and useful.
 
Where did Gopher come from?
 
"Born" in April 1991, gopher began as a project at the Microcomputer, Workstation, and Networks Center at the University of Minnesota to help people on campus get answers to computer-related questions.
 
At the time, the computer center staff had accumulated answers to thousands of questions regarding computers and software.
 
What was needed was an easy and efficient way to deliver this information to students, faculty and staff. Thus, the creation of Gopher reaffirms the adage that necessity is the mother of invention.
 
Why is it called Gopher?
 
The name "Gopher" is appropriate for three reasons:
 
1. Just as a real gopher successfully navigates beneath the prairie, the Internet Gopher tunnels through the invisible paths of the Internet to help you find the information you want.
 
2.The name refers to someone who fetches things or provides service for other people.
 
3.The Golden Gopher is the mascot of the University of Minnesota.
 
 
 

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