What is HTTP, URL and Search Engine - RLMD Technical

What is HTTP, URL and Search Engine

What is HTTP?

HTTP, Hyper Text Transfer Protocol is an application level protocol used to transfer data over the web. There are some rules of HTTP by which web browsers and servers exchange information over TCP / IP connections. The HTTP server is a program that listens to the HTTP request on the machine port. The HTTP client or web client opens a TCP / IP connection to the server via a socket, transmits the request to the document, and waits for a response from the server. When the request response sequence is completed, the socket closes. Therefore HTTP is a transactional protocol (transactional). The duration of the connection corresponds to a single request-reply sequence, which is called a transaction.

How does HTTP work?

HTTP is a request response protocol. A request consists of the following

* a request line

* Request headers

* Entity.

A response line sent by an entity server

* A status line

* Response headers.

* Entity.

Entity in requests and responses can be thought of as a payload that can be binary data. Others are readable ASCII charactere | When the response is complete, the browser and server may end the TCP / IP connection or the browser may send another request.

What is a URL?

The URL is an abbreviation for Uniform Resource Locator. The URL is the global address of the document and other resources on the World Wide Web. The first part of the address represents the protocol and the second is the IP address or domain name where the resources are located. For example, the URL below points to two different files on the domain www.nyise.org. The first shows the file located in the "fanny" sub directory on the NYISE web site. And the other is to receive the web page through HTTP protocol. http://www.nyise.org/fanny/index.html 

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

Search Engine:

Search engines are used to find information on the Internet. When we don't know where to start. The search engine allows the use of keywords to search the Internet site. Search engines use "robots" and "Crawlers" to find and index words on a web site. After that, the search engine matches the keyword given in the search with the words included in the index.

I WWW.Google.com, WWW.altavista.com, WWW.hotbot.com, WWW.Yahoo.com, www.askjeeves.com are some of the different search engines.

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What is www Browser and Web Server - RLMD Technical

What is www Browser  Web Server

www browser:

A web browser is a program used to view files on the Internet, including images, text sound and video. With the help of graphical browser, multimedia such as images and videos can also be viewed on the Internet. "Mosaic" is the first graphical web browser developed in 1993 by the National Center for Super Computing Applications, University of Illinois. Mac Andreessen and six of his fellow students worked on a university sponsored computer project to create a program to create Mosaic browsers. This program contributed to making the World Wide Web a keynote to Internet tools. Mosaic changed the text only www to a Microsoft Windows-like environment. With the introduction of Mosaic, the data transported by the Web grew at a rate of 10,000 in six months.

Web Server:

A web server is a computer that preserves the web page or application located on the server, representing the computer and server hardware parts, while the application is a software part. The server transmits graphics, sound and video to the web browser. The web server is also called an HTTP server, as it uses hypertext, transfer protocol (HTTP) to send web pages to the web browser.

The connection between a web browser and a web server is called stateless. When you send a request for a web page to a web server with the help of a browser, the server checks the validity of the request made for the HTML document. The server then sends the web page to your web browser and the connection is closed. The web browser connects to the web server only when the web page is requested to be reloaded and refreshed. You can provide web server facility by paying some fee. Those are also called commercial web servers. Free web servers can also be used, which are called freeware. Microsoft Internet Information Server (ITS) and Netscape Web Server are some of the well-known commercial web servers. Apache is a famous freeware.

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What is Domain Name System and Wolrd Wide Web

DNS Domain Name System:

DNS is a system on the Internet that allows a clear name for the address of each computer connected to the net and is used universally. Therefore, both the user and the application can use DNS name instead of IPnet's numeric address. This has many advantages and the fact that the name is a much easier and simpler method to use than a number. This allows the organization to keep the names of machines, services and e-mail addresses etc. independent of the specific number addresses that the working systems may be using at the time. Such as when changing the topology of the net or when changing the provider to access the Internet.

Technically, DNS is a database distributed over the Internet as a hierarchy. There are innumerable servers that find this out by interacting with each other and by translating the names to the respective IP addresses by the customer applications that contact them. Connection can be established. Each part of the database has a replica on at least two servers and it determines the redundancy factor. The biggest reason behind the growth and use of DNS on the Internet was the amazing increase in the number of connected machines on the network. Initially, the link between the number and the IP address was created by a ready-made list in the host file (Host.txt) which was updated every time a new system was added and needed to be on every computer connected to the Internet.

Larger installations have innumerable different groups of names to organize. This includes users and their passwords, names and network addresses for computers and accounts. Keeping this data updated on all computers has become very complicated. Hence the database is now kept on only a few systems.

For Internet users to access a web site, their computer needs to know the address of the web server hosting that site. Computers on the Internet recognize each other by number rather than letters or words. Each web site on the Internet has a domain name and numeric address. Which is called (IP address) Internet Protocol address. (Example, 205.139.94.60). Though this number is simple for computer but difficult for internet users to remember. Hence the need for a domain name. 

World Wide Web:

The World Wide Web (also known as the Web or www or W3) is an area of ​​the Internet that has achieved amazing achievements over the years. Many people consider the web to be the internet, whereas the web is only a part of the internet but a main part is made up of web sites, sites where someone has kept files and which are connected by people connected to the internet. Can be accessed. All files are of different types, text, graphic, video or sound etc. and are located on computers around the world. It has a wealth of information on many topics.

These files can be obtained by IP address and http protocol (Hypertext Transfer Protocol). The Web works on the Client-Server Model. You use a client program that sends your request to the server for information. The server receives the information and sends it to the client. The browser software used to access the web is called a browser. Netscape Navigator and Microsoft Internet Explorer with the help of well-known browsers, we can view graphic files on the web. There are also some text-only-browsers such as Lynx.

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What are Protocols and TCP/IP Protocols

What are Protocols?

The protocol is the framework of rules required to transmit data between two devices. The protocol describes the following:

1. Which type of error checking is to be used.

2. The method of data compression method, if any.

3. The method used by the sending device to explain that the transmission has been completed.

Protocols determine the manner in which computers are used to exchange messages and the format of the message that is sent. It all depends on the particular task. These tasks can be anything. Such as message exchange between networks, e-mail exchange, establishing remote connection, file transfer, etc. Two networking models support this. The first model is TCP / IP, a suite consisting of several protocols (TCP / IP Suite). In this, each protocol works to solve a particular communication problem. The second model is OST which is based on the International Standard. 

What is TCP / IP?

It is a suite of data communication protocols. The name TCP and IP are just two of the many protocols that make up this suite. Transmission Control Protocol (TCP) and Internet Protocol (IP) are the names of the two most important protocols that are included in the TCP / IP suite.

TCP / IP came into existence in 1969 as a result of research conducted by the Department of Defense (DOD) on the networking protocol. In 1968, the DOD Advanced Research Projects ARPA began research on network technology that is now packet switching agency. The focus of this research was to establish communication among the DOD community. The name of this research, which initially formed a network, was called ARPANET. As a gradual form of Internet, TCP / IP is of major importance in the development of the Internet. The TCP / IP protocol was born in the early 1980s. Year was born. In 1983, he became the standard protocol for ARPANET. Given the history of TCP/IP suite, they are often called Internet Protocol Suite.

Internet Protocol:

IP is a connectionless protocol which means that IP does not exchange control information to establish a connection before data transfer, which is called handshake. Conversely, the Connection Oriented protocol determines whether it has reached a state of receiving data by exchanging control information before sending data to a remote computer. When the handshake is successful, the connection is established. To establish an IP connection depends on the protocols of the second layer if the connection Oriented services are required. IP also depends on the second layer protocol for error detection and error recovery. IP is sometimes called an untrusted protocol, because. It does not contain error detection or recovery code.

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Guidelines for Internet Communication

Guidelines for Internet Communication:

Write a short message:

A large number of messages are transmitted over the Internet daily. To reduce traffic on the Internet and to simplify the communication load on the recipient, the length of the message should be minimum.

Write the relevant answer:

When replying to a message, include only the part of the previous message that is related to the reply. Some short forms can be used for e-mail communication. Such as FYI (for your information), BTW (by the way) and :-) (Smileys) to address expressions in messages.

Also include the return address information:

Configure your e-mail client in such a way that it also has a return e-mail address. Also include alternate means of communication when sending messages. Such as telephone number, home address. etc. Most e-mail programs allow us to create a signature file in which your name and related information are automatically added to the end of the message.

Write the topic in detail:

Ordinary subject messages such as information, or the subject not being written, are often ignored by the recipient who has a large number of e-mail messages, use small, message-related topics.

When replying, mention the original message:

While replying to the message, delete unnecessary portions of the original message received and leave out the specific points to be answered. Then add the answer after each point.

Accept on receipt of email:

Be sure to let the sender know when you receive the message. Check your email regularly. The sender of the e-mail is expecting a quick reply. Check your e-mail account in a span of few days and make sure that all the mails sent by you are read or not.

Timely reply:

Please read mat mail and reply soon. If you are not able to check your e-mail regularly, then a large number of mails become uncontrolled. If you regularly receive a large amount of mail, you can arrange it using the add-on utility.

Do not send personal messages through

newsgroups or mailing lists:

If the message is for any one person, do not send it through the newsgroup or list that many recipients receive. Always look at the address line above the message and make sure that you own them. Sending the answers you want to send.

Do sarcasm, slander and laughter in a joking 

manner:

Often a joke made with a good mindset is also misunderstood. Include a conversation style in your message only when the recipient is familiar with your personal style.

Do not publicly criticize other users:

Decent conversation is better than impulsive or rude communication. In case there is a need for a stringent reply, then we stop using email. Talk to that person directly. 

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Major Components of Internet, www , Email, Usenet, Telnet, FTP

Components of Internet:

1. World Wide Web:

The World Wide Web (also known as Web or www) is a system of Internet servers that support Hypertext to obtain various Internet protocols on an interface. Almost every type of protocol available on the Internet can be found on the web. Under this, email, FTP, Telnet and Usenet news come. In addition, the World Wide Web has its own protocols such as Hypertext 'Protocol or HTTP, we will read about it later.

The World Wide Web provides only one interface to access all these protocols. this. Provides a simple and user-friendly environment. Now it is not necessary that in all these protocols we are skilled up to the command level. The web collects all of these and creates a system. Because of this quality and because the web is capable of working with multi-media and advanced programming languages, it is the fastest-growing part of the Internet.

All actions on the web depend primarily on hypertext as a means of obtaining information. Hypertext is a document that contains words to connect to other documents. These words are called links and are chosen by the user. A hypertext document can contain links to many documents. In the context of the web, words or graphics serve as links to other documents, images, video and sound. The web is a complex virtual web for connectivity between numerous documents, graphics, video and sound. To create hypertext documents for the web, we have to use HTML (Hypertext Markup Language).

In HTML, tags are placed in the middle of simple text to create document formatting, visual display such as font size, italic or bold and hypertext links. Graphics and multimedia can also be inserted in an HTML document. HTML is a developing language, in which new tags are added to each new version. The World Wide Web Consortium (W3C), run by Tim Berners Lee, the father of the web, combines efforts to standardize HTML. The W3C now calls it XHTML and considers it an application of XML language rules.

The World Wide Web is made up of files, also known as pages or home pages. And which contains links to documents and tools all over the Internet.

The web provides us with a variety of experiences including multi-media presentations, real-time collaborations, interactive pages, radio and television broadcasts and automatic "push" of information on client computers. Programming languages ​​such as Java, Javascript, Visual Basic, Cold fusion and XML further enhance the capabilities of the web. The information stored on the web is stored by information stored in the database. For this reason, the web is not a permanent element, but is in a state of continuous development.

2. Email:

Electronic Mail or e-mail allows local and computer users around the world to exchange messages. Each user of an e-mail has its own mail box, in which messages are sent. Messages sent by e-mail reach within a few seconds.

An important aspect of e-mail is the option to send electronic files to a person's e-mail address. Non-ASCII files or binary files can also be combined with e-mail messages. These files are called MIME attachment. MIME stands for Multimedia Internet Mail Extension and was developed by e-mail software to help handle various types of files. For example, a document created in Microsoft Word can be associated with an e-mail message, and can also be received by the recipient with the help of an appropriate e-mail program. Many e-mail programs such as Eudora, Netscape Messenger and Microsoft Outlook allow to read files written in HTML which is itself a type of MIME.

3.  Telnet:

It is a program that allows logging in on computers on the Internet, and provides on-line databases, chat services, library catalogs and more. Telnet session only contains text and not graphics. To login on a computer, it is necessary to know its address. It can be made up of words (Locis.loc.gov) or number (140.147.254.3). For some services, our remote computer needs to be connected on a specific port. In this case, also type the port number after the Internet address. Example - Telnetnri.reston.va.us 185.

Telnet is available on the World Wide Web. Of course, the most public wedge-based tool available by telnet is library catalogs, while most catalogs have gone on the web. The link established for telnet looks the same as any other link, but it launches the telnet session to establish the connection. For this task, it is necessary to install telnet program on the local computer and also configure it on the web browser.

With the increasing popularity of the web, Telnet is less used to receive information over the Internet.

4. FTP:

FTP stands for File Transfer Protocol. It is both a program and a method used to transfer files between computers. FTP is an option that allows users to transfer files from thousands of host computers on the Internet to their personal computers. FTP sites include books, articles, software, games, images, sound, multi-media, course work, data sets and more.

If your computer is directly connected to the Internet via ethernet cable, you can use WS_FTP for file transfer for many PC software programs such as Windows. FTP transfer can be done on the World Wide Web without any specific software. In this case the web browser is sufficient. Whenever you download software from web site on your locale machine, you are using FTP. You can also find FTP files through search engines, such as FTP Find, located at http://www.ftpfind.com/. This option is the simplest because it does not require knowing FTP program commands.

5.  E-mail discussion group:

- One utility of the Internet is that it allows people worldwide to communicate by e-mail. The Internet is home to a particular community of people, who arrange active discussion on topic-centered forums distributed by e-mail. These are operated by software programs. Of course the most important program is listserv.

Listservs cover a wide variety of subjects, most of them teaching-related. When you subscribe on the list server, the messages are sent to your email box by another subscriber. You can subscribe to a list server by sending an e-mail message to a computer program. The list server is located on computer networks worldwide. This program collects the information related to the subscription and performs the task of sending and receiving messages to the subscriber. To participate in the list server discussion group, you must have an e-mail account. To see an example of a site providing a searchable collection of email discussion groups, visit Tile.net at htpp: //file.net/. Majordomo and List proc are two other programs that operate the e-mail discussion group. Commands list is the same as serve for subscribing and your list membership.

 6. Usenet News:

Usenet News is an international electronic bulletin board system on which billions of computer users worldwide can exchange information on thousands of topics. The major difference between Usenet News and E-mail discussion groups is that Usenet messages are protected on a central computer and users have to connect to these computers to read and download the messages posted on these groups. This is different from e-mail delivery, in which messages arrive in the electronic mail box of each list member.

Usenet itself is a group of machines that exchange messages and articles from the Usenet Discussion Forum, called Newsgroup. Usenet managers control their site and consider which newsgroups to sponsor and which remote newsgroups are allowed to enter the system.

Today thousands of Usenet newsgroups exist. Many of them are education related, and many newsgroups are organized on entertaining topics. Usenet discussion also includes computer related work. A very small number of e-mail discussion groups are also functioning like Usenet groups.

Usenet newsfeed can be read through various types of newsreader software programs. For example, Netscape suite comes with a newsreader program called Messenger. The newsreader is also available as a stand alone product. Chat and Instant Messaging:

The chat program allows Internet users to interact in real-time by typing. It is sometimes included as a property of the web site itself. Where users can log in to "chat room" and exchange messages and information on the topics displayed by the site. There can also be extended forms of chat eg, America Online is known for providing its numerous topical chat forms.

Internet relay chat is a service through which users can chat among themselves from anywhere in thousands of channels. These channels are usually based on specific topics. But if some subjects are meaningless, then necessary topics are discussed. To access IRC, it is necessary to use an IRC software program.

The second type of chat is called Instant Messaging. In this, the user can chat on the web by typing with another user who is logged in. The most famous is Instant Messenger of America Online. ICQ, MSN, and Yahoo also feature their chat programs.

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How Internet was Developed Brief History of Internet

How Internet was Developed Brief History of Internet:

This word (Internet) brightens many shapes on our psyche. The most important of these is hundreds of thousands of computers and computer networks sharing information. This is the hardware aspect of the Internet. The second aspect is its utility that provides a wide range of services such as email and others, which we will learn later in detail. The second figure comes that each has to do his own work. The government tried to authorize it but it failed.

The surprise is that the Internet is a product of military organization. (Pentagon) The Pentagon’s Advanced Research project Agency (ARPA) funded funding for its creation in 1969 called ARPAnet. The main reason for this was very simple. Develop a reliable computer communication network for military use that can function even after the damage caused by a nuclear attack. This goal is accomplished by dividing the data being sent into small packets so that it can reach its target by a different route. This 'Packet-Switched' network can continue communication even after a nuclear attack, because packets can use another route if one communication route is broken.

The method developed for interconnecting ARPAnet computers and communicating data was called TCP / IP (Transmission Control Protocol / Internet protocol). ARPAnet allowed engineers and scientists working for military organizations to share computers and computer equipment in the United States. The second aspect is that computer scientists developed a medium for the exchange of messages. This quality of e-mail transformed the network into a new communication medium. Initially, ARPAnet was limited to only those organizations and individuals who had US government security and who were working on government contracts. It soon joined the non-governmental, parallel educational network, Usenet News, which arrived in 1979 and soon developed into the Internet. In the 1980s, the US government established five supercomputer centers through its agency, the National Science Foundation (NSF), which became the main nodes of the Internet (Nodes) to connect networks of universities and research laboratories.

The innumerable computers connected to the Internet are spreading wonderfully. By 1983, there were less than 500 host computers, most of which were government labs and educational institutions. The rest of the academic community harnessed the potential of information communication and by 1987 there were approximately 30,000 host computers at various universities and research labs. By 1995, this number had risen to 5 billion.

Internet access was a difficult task in the early 1980s. But apart from this, there was no other way to connect with universities and research labs around the world in such a fast and simple way. So Internet users brought their software to participate in network discussions. They created documents and software libraries on the network that were available to all users. During this time the Internet was confined within the narrow limits of academic and research labs.

In 1980, another computer related incident occurred - Personal Computer became more popular. Earlier, only Mini Computer or Mainframe were used in business. But now it went completely to microcomputers, which are called desktop computers, personal computers or PCs. It is a stand-alone machine that does not have the ability to share data (date and resources). Concept of local area network (LAN) became important to overcome this shortage. Wide area network for large companies. (WAND also came to pass. E-mail became an everyday communication medium with their existence.

As the price of PC came down, more and more people came to computer. These people have been asked to connect their machines to other machines. As a result, on-line services such as Telnet and Compuserve came into existence. For some charges, the user can connect to them, and can communicate with other users on the same service. One can also download the repository of information and software available on them. With these on-line services came the concept of Bulletin Board Service (BBS), which connects a person to the computer in their environment and facilitates the exchange of information and software. Initially, these private networks, both corporate and commercial, had different hardware and software platforms and could not communicate with each other, but soon TCP / IP was used by All these networks, BBD denominations and households, PCs connected to Internet technology in office, TCP / IP were connected to the Internet, which we are seeing in its present form. To connect any network or computer to the Internet, only TCP / IP should be used. So that information can be communicated. In this way, the Internet Network of Networks was created.

In its early stages it was wholly or somewhat controlled by US government agencies, first ARPA then NSF but now it has become a separate, in some ways uncontrolled and global element. Various sources are helpful to its nodes. In the 1980s, the ARPA was reorganized, disbanded and the American Security Network distanced itself from the Internet. Its support by the NSF continued, and until recently, NSF paid to connect computers in educational institutions and government agencies everywhere in the USA to the Internet. Gradually, the NSF ordered commercial networks to be connected to the Internet, initially for teaching and research purposes, but primarily for commercial use. This gradually increased the business use of the Internet, as the commitments also started to loosen. Companies became the main user in 1995. April 1995 dropped out of the NSF scene. And today the US government has no role in operating or maintaining the Internet. It is now self-operating.

Two other major developments are responsible for the rapid expansion of the Internet. First took place at CERN, a European High Energy Physics Lab near Geneva. There in 1990, Physicists created a software for publishing, searching, and receiving information on the Internet, a means for scientists to share documents with their peers sitting far away. It was called the World Wide Web (www).

The second development took place at the University of Illinois, where a student named Marc Andressen created a graphical browser named Mosaic from which information could be obtained from www. Both of the above developments brought the Internet from laboratories into the mainstream of life. In the last year, the development of www was more rapid than the rapid expansion of the Internet. 

Internet is in authority?

Nobody really has the right on the Internet. No single person or organization can control the Internet completely. It is more of an idea than a tangible entity, the Internet rests on a physical infrastructure that connects one network to another. Many such organizations. Corporations, government, schools, private individuals and service providers are those who have authority over some part of this system. But no one community has complete authority over it.

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