eli5: How was the internet made?
The internet started as high speed communication between universities and academic centers.
That was the initial groundwork of the internet. Universities and research centers all paying the money to wire themselves together so they could pass information from on another faster. And then they figured out that if A was connected to B, and B was connected to C, they didn’t have to build a new wire connecting A to C, they realized they could just set it up to connect through B.
Do this but with dozens of locations across and you get “Arpanet”. Or Advanced Research Projects Agency Network. Look up “arpanet” map and you can see all the locations that were included in this original network. And looking at that map you’ll see it kinda looks like a web, like a spider web, that’s where the nickname “the web” came from. Because when you mapped out all the connections that’s what it looked like.
Anyways. That was the initial network infrastructure, wires connecting research locations so they could share data. That was the base ground.
Then over the years it was just expanded and expanded and expanded gradually.
It grew, more than was made. DARPA wanted to transfer large amounts of data quickly. Turns out that the best way to do that with the technology of the time was with electricity transformed into sound and transmitted over the phone network. So we’ve got two computers that can talk to each other, through some custom hardware called a modem. “Cool!” says a third group of people. They want in on that. So they build their own modem. Now we’ve got A, B and C. D, E, and F hear about this, do the thing, and so on and so on. Data transmission gets faster, more processes are invented to coordinate everyone, automation gets involved, businesses build things, the internet is born.
Older computer programming needed to be as lean as possible so the dominant system was “master and slaves”. There was one super unit that decided who should do what.
Problem: the military wanted to get rid of this system as a hit to the master computer would have downed the entire military communications. Imagine it like a city with a post office, and everyone allowed to exchange things only by using such office; if someone blows up the office, no one can comunicate.
Studies started to satisfy this but it was soon clear the benefits were too big to be limited to military only. The World Wide Web, a network for everyone, was born.
What is the internet: internet is a communication design based on labeling every place and every message, in a way any computer can read it and redirect it to its destination. This system allowed the grid to keep working and transmitting data as long as there was ANY path between transmitter and receiver. Basically there was no master that could be “killed”. Your pc would label a set of data with “I made it, give it to Jim”, shoot it into the cable, whatever pc “hears” that, will relay the info toward Jim, it keeps going until it gets to the recipient.
In other words, imagine in your entire city, everyone receives a map with the name of everyone. Anyone in town can give a packet labeled “for NoComunity877” to a random guy, and people will just pass that to eachother in the general direction of where you are, sooner or later you get the packet.
What is the basic principle that was missing before: the set of rules that prevent computer to overlap on other computer messages. This was the core issue for which the “master and slave” was used. In a master/slave system only a single unit can decide who transmit when, and keep king the line clean is easy.
The internet is instead a system where any unit can transmit in a way that doesn’t ever overlap. Basically as soon as a unit transmits, the otherS are forced to silence. There’s timing and so on to prevent a single unit to abuse it, so other units will have their time to transmit too. Imagine it as a very polite family meeting where everyone can speak, everyone let other finish before having their say, and no one makes infinitely long sentences monopolizing the conversation.
What most people think of the Internet (graphical websites, youtube, etc) didn’t even exist until the mid-1990s. Early networks were entirely text-based. The original networks connected government and military institutions and universities (the original .gov, .mil, .edu top-level domains).
The Internet Protocol (IP) was developed as a method of sending data via small packets, similar to mailing letters via the post office.. The sender and receiver didn’t care how it got the data. I’d tell you a UDP joke but you might not get it.
The most widely used version was IPv4 which had 4-billion addresses. Which may sound like a lot, but institutions could reserve large chunks of addresses which reduced the number of available addresses. Until address translation/spoofing came around which allowed reusing network addresses in a local network. And now IPv6 is widely used.
Several programs/protocols were developed for sending email, transferring files (file transfer protocol = ftp), telnet (non-secure version of ssh before ssh existed), gopher, wais, etc.
The WWW started in early 1990s, HTML was very basic and only supported text with some inline static graphics. It was at this point where companies started ‘getting online’ by creating websites, and the explosion of the ‘dotcom’ companies in the late 1990s.
They wanted to deliver vast amounts of information over the Internet. And again, the Internet is not something that you just dump something on. It’s not a big truck. It’s a series of tubes. And if you don’t understand, those tubes can be filled and if they are filled, when you put your message in, it gets in line and it’s going to be delayed by anyone that puts into that tube enormous amounts of material, enormous amounts of material.
tl;dr: It is simply a [series of tubes](https://en.wikipedia.org/wiki/Series_of_tubes)