The World Wide Web (called WWW or W3 in short) is the most popular and promising method of accessing the internet. The main reason for its popularity is the use of a concept called hypertext.
Hypertext is a new way of information storage and retrieval which enables authors to structure information in novel ways. An effectively designed hypertext document can help users rapidly locate the desired type of information from the vast amount of information on the internet.
Hypertext documents enable this by using a series of links. A link can be shown on the screen in multiple ways, such as a labeled button, highlighted text or different color text than normal text if your computer has a color display, or author-defined graphic symbols.
Link is a special type of item in a hypertext document which connects the document to another document that provides more information about the linked item. The latter document can be anywhere on the internet (in the same document in which the linked item is, in the same computer in which the former document is or in another computer which is at the other end of the world). By “connect” we mean that a user simply selects the linked item (using a mouse or key command) and the user almost immediately sees the other document on his/her computer terminal.
The concept of hypertext can be best illustrated with the help of an example. Let us assume that the screen of your computer terminal has the following hypertext document currently displayed on it. This hypertext document has the following two links, which are shown on the screen as highlighted (bold and underlined) texts:
1. Center for Development of Advanced computing (C-DAC) - Let us assume that this link connects the current document to another document, which gives detailed information about C-DAC and is located on a computer system at C-DAC in Pune, India.
2. Multimedia systems Research Laboratory (MSRL) of Panasonic - Let us assume that this link connects the current document to another document, which gives detailed information about MSRL of Panasonic, and is located on a computer system at MSRL of Panasonic in Tokyo, Japan.
Now if you use your mouse to click anywhere on the link Multimedia Systems Research Laboratory (MSRL) of Panasonic, within a few seconds you will find yourself connected to the computer at MSRL of Panasonic in Tokyo. A document containing detailed information about MSRL will be displayed on your computer screen.
Hypertext documents on the internet are known as Web pages. Web pages are created by using a special language called Hypertext Markup Language(HTML in short).HTML is a subset of the more generalized language called standard Generalized Markup Language (SGML in short), which is a powerful language for linking documents for easier electronic access and manipulation. HTML is becoming a de-facto industrial standard for creating web pages.
The WWW uses the client-server model and an Internet protocol called Hypertext Transport Protocol (HTTP in short) for interaction between the computers on the internet. Any computer on the internet which uses the HTTP protocol is called a Web Server. And any computer which can access that server is called a Web client. The use of the client-server model and the HTTP allows different kinds of computers on the internet to interact with each other. For example, UNIX workstation may be the web server and a windows pc may be the web client, if both of them use the HTTP protocol for transmitting and receiving information.
The internet is a huge network of computers which links many different types of computers all over the world. It is a network of networks which share a common mechanism for addressing computers, and a common set of protocols for communications between two computers on the network.
What Is HTTP ?
HTTP (Hyper Text Transfer Protocol) is a stateless protocol. It means fresh connection to the server is required for every item to be downloaded. It transfers hypertext across the internet. Clients and web servers communicate via this protocol. Following are the basic steps of this protocol.
a. Client opens socket connection to the HTTP server, typically over port 80.
b. Client sends HTTP request to server.
c. Server sends back response.
d. Server closes connection.
What is a HTTP Proxy Server ?
It is a program that acts as an interface between a client and a server. It receives requests from the clients, and forwards them to the server(s). The responses are sent back in the same way. A proxy thus acts both as a HTTP client and a server. Request from a client to a proxy server differs from normal server because the Requests in one way.
The complete URL of the source being requested must be specified because it is required by the proxy to know where to forward the request.
Important Internet Applications
1. TELNET
2. FILE transfer protocol (FTP)
3. Electronic mail (Email)
4. Gopher
5. Internet Relay chat (IRC)
6. Usenet News
7. World Wide Web (WWW)
New Robotic Vessel extends deep ocean exploration by Lihui. AUV means Autonomous Under - Water Vehicle. France, Russia, Japan and the US have these vehicles are very costly. Now, China has also developed its own AUV Cr 01. It can go down up to 6000 meters. It can remain under water for a long tome and take still and video pictures.
Exploring the deep ocean is a technological challenge. The pressure of the sea water is one challenge. It also risky and dangerous. But, it offers economic and scientific rewards. We can know about the Topography and the Hydrology of the seabed. We can explore under water mineral resources and recover sunken objects.
AUV is torpedo-shaped. It is 4.4 meters long and 0.8 meters in diameter. It is big and heavy, as it weighs 1300 kilometers. It can use durable batteries. It can move at a speed of 2 knots. The AUV yses 5 ranging sonars to avoid collisions. For navigation, it uses a baseline acoustic system. This can cover an area of about 40 kilometers. The robot can raise automatically an alarm and flash lights in case of an emergency.
To collect samples, the robot has no external devices. It has a camera that holds four hours of tape. With this, it takes upto 3000 photos. It uses side scanning sonars for locating mineral deposits. Its profiler can tell us about the depth of these deposits.
The Chinese tried their first AUV in 1985. In 1992, they turned to Russia for help. The china Ocean Mineral Resources R&D Association has plans to explore the pacific for mineral resources. It plans to get one more AUV with the help of other countries.
first, u need to goto
Start then run
type regedit in the box
next go to the folder
HKEY_LOCAL_MACHINE\System\current controlset\services\VxD\MSTCP
now find the string default Rcv window
now edit the number to 64240(was 65535)
reboot your computer now double increase your net speed.
Internet
Internet is one of the great and biggest contributors worldwide. Internet has bought lot of changes in many aspects of life. Internet was introduced due to some research done in early 1960’s and was previously named as ARPANET and then INTERNET was introduced. Every internet connection is associated with an Internet protocol number through which computer recognizes who is who. Internet provides lot of benefits to people in all professions. The use of internet has developed remarkably and one of the main reasons for it to happen is because it is user friendly and flexible. Now-a-days most of them have computers at home and can easily get the internet connection fixed to their computers; previously internet was only available for internet developers and military people however now internet is not restricted only for one area of profession, it is used by various sectors in the world. Internet has grown to such an extent that people log on to view the news every day, for many people internet becomes a habit and they would feel something is missing in their life if they don’t log on to internet even a day.
Internet has now become a necessity at all the places, previously it was only used by computer experts or engineers but now awareness of internet has widely spread and people who don’t have access to internet at home visit cyber cafes to collect the required information or get their work done. Internet is used in many businesses to sell and buy products online. Real time auctions takes place in one of the most popular sites called “E-bay”. There are different types of internet providers in the market; operator should decide which internet service to use. Internet is a business tool as it facilitates in creating website, by having your own site, business man can write useful and quality content about various products or services the business offers and advertise it to the general public. Provide your complete contact information, most importantly include customer service email address or contact number to know that you are real people who can answer everyone’s queries about different business offers. Always keep in mind that your site content should be self explanatory so that people stumble upon your site to see the latest updates, make sure that your site gets maximum exposure which in turn helps your business grow. Advertising your business on internet is one of the easiest ways of reaching people.
Advantages of internet –
1. Availability of information - People have chance to read and learn lot of information by surfing net. Google and yahoo are the popular search engines which help in providing important updates on any and every topic.
2. Online Library - Students have the availability to use library online and added advantage to this is some of the online library provides free service.
3. Communication - Communication has become lot easier with the advent of internet. You can chat, call, video conference or email your friends, family members as internet provides all these services free of cost.
4. Online Shopping - People who wish to shop online can log on to internet as it enables online buying and selling. Online shopping is secure, it helps to place orders and get latest updates on different products available.
5. Work at home - Internet helps to generate revenue as there is lot of work at home programmes available worldwide through which people can make money online. Don’t get hyped by get rich quick schemes available which are absolutely scam. There are lot many genuine work at home jobs available which helps to earn decent income online.
6. Job searches – Job searches became lot easier through internet as it allows viewing web classifieds which posts job vacancies in various sectors.
7. “Internet is a service provider” – In this modern economy, internet provides valuable services to the public. Banking sectors allow internet banking which is online banking, Movie tickets can be booked online, booking tickets to travel is allowed, hotel reservations can also be done. All the above services are provided by internet.
8. Entertainment – Internet allows you to play interesting and amusing games. Internet entertains in different ways; it lets you watch movies, listen to songs etc. There are numerous sites which allow downloading latest songs and movies. There are various social networking sites, through which you can share your views or thoughts and make friends with likeminded people.
9. Board Results – Usually board results are also uploaded in internet through which students can view their exam results online as it is less time consuming.
10. Real time news – Internet updates real time news about the event happening across the world.
Disadvantages of Internet –
1. Porn pictures and immoral content – Internet has lot of sites which contains porn pictures and corrupted content which influences young and teenage children in negative way.
2. Spread of virus – Virus usually spreads from one computer to another. Computer is affected with virus when you download movies and songs from various sites. This might affect the valuable data in your computer.
3. Games and Fun - Internet provides many fun activities through which individual tends to waste lot of time either playing games or listening to songs etc.
4. Hacking – There are many internet hackers in the market, who can get access to your valuable data stored in your computer.
5. Misuses of photograph – Generally people have the habit of sharing their photograph while chatting or on the social networking sites which can be misused to a very bad extent. It is always advisable not to upload your photographs on those sites to be on a safer side.
6. Spamming your inbox – Unknown recipient sending bulk emails might block the whole system.
7. Tracking credit card numbers – Always be little careful while shopping online and giving your credit card number to purchase any product, now-a-days tracking credit card numbers has become lot easier therefore give your credit card numbers only on trusted and protected sites.
Never encourage illegal users who play and misuse with photographs or porn pictures, report their activities actively so that each one of them can lend our helping hands in minimizing the illegal activities conducted by people across the world. In this modern economy internet marketing and internet business is recognized immensely and therefore the advantages of internet are growing successfully and continuously.
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Web Hosting
Web Hosting is a service offered by web hosting providers to the individuals and organizations to make their websites accessible on the internet. Depending on the requirement, one can avail different types of web hosting such as shared hosting, dedicated hosting, virtual private hosting, cloud hosting etc.
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