Aug 2017
19

INTERNET & APP

INTERNET and Applications ?

INTERNET

The  Internet is the World’s largest network of computer networks.  If you have a computer you can hook it to the Internet.  There are more than 100 million users on the Internet, and they are growing rapidly by the day.

 

History of Internet

In 1969 the American defense department wanted to connect all  the computers in the Department of Defense (DOD) offices and military research contractors including a large number of universities doing military funded research.  That network was called Advanced Research Projects Agency Network (ARPANET), was also called DARPANET,

 

the D for defenses.  It started in a small way connecting three computers in California with one in Utah, but quickly grew to span the whole of America.  It was very successful and all the universities wanted to get connected to ARPANET. At one stage the military officials wanted to preserve the unity of the DOD, and so divided the network into two parts:

 

  • ARPANET
  • MILNET (Military Network)

These two parts remained connected with a technical scheme called internetProtocol (IP)).  The word protocol means “rules for meeting a person/king”.  On the Internet, if we want to contact a person on another network, we need a protocol.  Network designers have designed several protocols now, and some of them are as follows:

 

  • Simple Mail Transfer Protocol (SMTP)
  • Point-to-Point Protocol (PPP)
  • Hyper-Text Transfer Protocol (HTTP)

Screenshot_2017-08-19-13-32-02_1

Hyper-Text Transfer Protocol secure HTTPS

 

Screenshot_2017-08-19-13-31-07_1

 

 

  • Transfer Control Protocol/Internet Protocol (TCP/IP)

Internet Protocol is a technical switching scheme, which enable a node of one network to communicate with a node of another network.  The American National Science Foundation then established another network of computers in America.  It permitted all the universities and research centers to hook on to their network National Science Foundation Network (NSFNET) and to contribute to super-computer research.  During 1990, many computers started hooking up to NSFNET, and as a result ARPANET outlived its usefulness and was shut down.  During 1994, several commercial organizations introduced networks across the globe.  They also designed protocols to communicate from one node of a network to another node in another network.  As a result of this we now have a network of so many different networks.  This network of networks is called the Internet.

 

Internet Applications

When your computer is hooked to the Internet, you are a member of an international group.   You can say that you are on the information superhighway and you can communicate with any member of the Internet any where around the world.  The capabilities of the Internet are numerous.  We list here some of the prominent capabilities.

 

ELECTRONIC MAIL (E-MAIL)

Electronic mail is the facility of sending text-based messages and letters to any Internet user.  It will not be surprising if all the post offices in the world shut down in the near future because of this facility.  If you are hooked to the Internet, you can send mail (letters) to your friend who is also on the Internet.  Everybody on the Internet has his/her own unique e-mail address.  Using which one can communicate with other e-mail users and that too very quickly.  We can also attach picture, sound, video or document files to the e-mail.

 

Signatures

Whenever we write a letter, we affix our signature at the end of the letter.  This facility has been included in electronic mail also.  The software we use for sending e-mail has the facility to create and modify our signature electronically.  The electronic signature is a text-based collection of one or two lines.  For example, my signature can be set as the following.

 

This signature is appended automatically to all e-mails and sent.  It is also possible to set the e-mail signature as a small diagram using text-based symbols.

 

Voice E-mail

In a usual (text) e-mail, we type the message in the body of the e-mail in text mode.  Recently, some companies have introduced software systems which support voice e-mail.  Such software is given as an enhancement to their usual software. After keying the address to which the e-mail has to be sent, we must speak the message.  This voice

 

e-mail travels just like the text e-mail and reaches its destination.  When the receiver opens his mail, the voice message of the e-mail is heard.

 

Considering the fact that computer users type an average of 20-30 words per minute and professional typists type an average 60-80 words, human speech averages 200-250 words per minute.  So voice e-mail is approximately eight times faster.  In voice e-mail technology, editing, spell checks, grammar and punctuation checks become redundant.  Pictures and photographs can also be sent along with voice e-mail messages.  One need not be online at the same time to hear the message.  The message packet reaches the mailbox, and the recipient can open and hear it at any time.

 

RESOURCE SHARING

Every Internet system has some files open for anybody on the Internet.  For example, every Ph D thesis of a university can be copied by anybody free of cost.  These file names and the protocols are advertised in newspapers or private communications or web pages.  Software companies offer the beta version of their new products available on the net.  We can download these files using File Transfer Protocols (FTP).

 

There are two types of FTP resources available on the Internet.  They are:

 

  • Anonymous FTP
  • Non-anonymous FTP

The anonymous FTP service is open to everybody on the net.  The user can log on to an FTP server without opening an account on the server.  He/she can just log on with the user ID (Identification) “anonymous”.  The system will then respond and ask your e-mail address.  Then it will ask for your (systems’) password.  After that you can download any file from the FTP server.  The anonymous FTP facility is available for Ph D theses, research reports, news, etc.  In the case of non-anonymous FTP, one can download a file only if one creates an account with the FTP server.  The user must already have an account, user ID and a password to download a file.

 

GOPHER

As the Internet became popular, people started working on a technology for resource sharing.  The resources (in the form of files) available on a server were to be shared by the Internet clients (users).  The first technology that people adopted was FTP.  The FTP service was found to be efficient for sharing and downloading files.  However, the FTP user bad to initially know the location of the file.  Browsing of information is not possible in FTP.  So it was very difficult for users to locate a file.  Then came a service called Archie.  Archie was developed as a searching, system for the files available on FTP.  The files available on ftp were called FTP space.  Archie helped users to search the FTP, space using keywords.  Archie was not a part of the FTP service; Archie and FTP were two different services.  One can first search for a file in FTP space using Archie and then download it using FTP.

 

In order to make it easy for the user, the University of Minnesota invented a new service in 1991 and named it Gopher, after the name of its mascot.  The Gopher service was first used in the campus-wide Information System of the University of Minnesota.  It became very popular during 1991-93.  Gopher is easy-to-use and also provides browsing of large files.  During 1991-93, several users began to keep their resources on Gopher servers because the University of Minnesota provided the server and client software for Gopher free of cost through the Internet.  The resources (files) available on Gopher are called gopher space.  Later, a search facility called Veronica was made available to search in Gopher.  Using Veronica, we can search for a file in Gopher using keywords and titles.  Gopher and Veronica are not two different services-Veronica can be got from the Gopher menu itself; they are coupled together.  Later, another search facility called Jughead was also developed.

 

Since the Gopher resources are arranged in simple linear forms, searching takes more time, and further it does not support multimedia features.  Bothe FTP and Gopher mainly have text-based resources.

 

A large quantum of FTP and Gopher-based resources are still available on the Internet.  However, things have moved to a better technology the World Wide Web.  Now some of the FTP and Gopher resources have migrated to WWW.  Most of the resources that can be linked through FTP or Gopher can also be linked through WWW.

 

WORLD WIDE WEB

The World Wide Web (WWW) is a collection of pages maintained on the Internet using a technique that is called hyper-text.

 

Hyper-Text

Hyper-text is a text of more than two dimensions.  Consider any text that is typed from left to right.  It has only two dimensions:

 

  • Left to right
  • Top to bottom

Left  to right is normally considered as the x-axis and top to bottom is considered the y-axis.  In hyper-text, one 2-D text is shown on the screen.  Certain words are highlighted.  If we click one of those highlighted words, more details about that word appear in another window.  We say that thes fdetails form the third dimension, the z-axis, that goes deeper into the text.  This can be done further on the smaller window also.

 

For example, consider the window shown.  The word Autonomous is appearing in a different color.  If we click on it further details on the autonomous status are shown in another window, as shown .

 

In this window, the word UGC is highlighted.  If we click on it, we get further information on “UGCs” as shown .

 

Web page addresses are similar to the one shown.  The acronym for Hyper-Text Transfer Protocol is http, and www for the World  Wide Web.  Pointers connect the web pages in multiple ways in the form of multiple linked lists.  For example, educational websites are arranged in one list, religious webs in another and similarly for other types also.  A site may be in more than one list.  Thus, we can go deeper into the text and know the details.  Each page of the Web is called a web page or website.  Every Internet-connected system may have a website.  If  you have a web page, you can keep any text, pictures, sound or even animation on your website.  Nowadays companies give a complete profile in text, picture and sound on their websites.  Text, picture, sound or animation kept on a website can be seen by anybody who browses the web.  Browsing the web means looking at various web pages one after the other, also called surfing the web.

 

 

 

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