What exactly is the Internet? A computer scientist explains what it is and how it came to be

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What exactly is the Internet? Nora, age 8, Akron, Ohio
The Internet is a global collection of computers that can send messages to each other. Basically everything connected to the Internet is actually a computer – or “baked into” it.
In the early 1960s, computers were used only for special purposes, such as scientific research. There weren’t many of them because they were big and expensive. A single computer and its attachments can easily fill a room. To exchange data, people would schedule a time to work together, and one computer would connect to another by telephone.
The United States government wanted a network that would allow computers to communicate automatically even if certain telephone lines were cut. Suppose you wanted to send a message from Computer A to Computer B on each of three types of networks. The first is a network with one central computer connected to all the others as speakers. The second is a network of these several hub and spoke networks with their own connected hubs. The third is a network where every computer is connected to several others, forming a type of mesh. Which one do you think would be more reliable if other computers and links were to be damaged?
The first network is vulnerable, because if the central computer is lost, then none of the computers can communicate. The secondary network is vulnerable because if any of the hub computers are lost, the path between A and B is cut. But in the third network, many computers and links can be lost and there will still be a way to connect A and B. So the third network will be more reliable.

Hot potatoes
An American engineer named Paul Baran worked on this problem at a company called Rand Corp. In 1962, he published a new theory of computer networks, which he called “hot potato networking.”
In Baran’s vision, the message would be broken down into smaller pieces – potatoes. When Computer A wanted to send its message to Computer B, it would send small potatoes to the neighboring computer. That computer would redirect him to the right path as quickly as possible. To ensure that messages are delivered quickly, pieces of messages are treated as if they are hot, so you don’t want them in your hands for too long.
The messages included a sequence number so that when it arrived at Computer B, the end computer, that machine would be able to put it in the correct order to get the full message.
Baran’s idea was implemented as ARPANET. This network was the modern forerunner of today’s Internet.
Instead of hot potatoes, the system got an official name, which we still use: “packet switched networking.” A potato was renamed a packet – a small piece of a full message.
Vinton Cerf, an American computer scientist, is known as one of the fathers of the Internet. He contributed many important ideas, including that the receiving computer can query the sending computer for a lost packet – which they sometimes do. This is called Transmission Control Protocol, or TCP.

A web of pages
Another important contributor was Tim Berners-Lee, a British computer scientist. Berners-Lee worked at CERN, the European Organization for Nuclear Research. He wanted to create a system for his colleagues to better share their research results.
Around 1990, Berners-Lee came up with the idea that a computer could hold a collection of “pages,” each containing text, images and links to other pages. He created a simple way for links to specify any computer – the concept of a URL, or Uniform Resource Locator.
Berners-Lee named the system the World Wide Web. He wrote the code for the first web browser, web page viewer, and web server, to deliver it. If you see a URL that includes “www” – that’s from the first word.
Berners-Lee may have been planning to use the web primarily to share text, images and files. But earlier work on the Internet made the web suitable for video and audio, too. YouTube, Instagram and TikTok are built using the same rules, or protocols, developed by Cerf and Berners-Lee.

The Internet of Things
Over the past 20 years, computers have become more powerful and less expensive. Now, a computer chip that can connect directly to the Internet sells for US$5 – much less than today’s laptops and cell phones (around $300) or yesterday’s desktop computers ($1 million or more!).
These low costs have led to billions of internet-connected devices. These devices include sensors. A smart thermostat monitors your home using a temperature sensor. A security camera keeps an eye on your front porch using an array of tiny light sensors.

These devices include actuators – mechanisms that control activity in the virtual world. For example, a smart thermostat can turn your home’s heating and cooling systems on and off.
Together, all these smart devices are called the Internet of Things, or IoT. The Internet includes not only computers and phones, but all these IoT devices. You could have a smart refrigerator with a camera inside it. If it detects that you have run out of milk, it will send a message to your mobile phone, reminding you to buy more.
Almost everything is connected to the internet now.
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This article is republished from The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/what-exactly-is-the-internet-a-computer-scientist-explains-what-it-is-and-how-it-came-to-be- 198132 .

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