Isn’t a torrent just, like…directly sharing a file from your PC? What’s all this business about “seeding” and “leeching”?
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Imagine asking someone to draw a picture of a dog.
In a typical direct download, someone has the picture of a dog, and they draw a copy of the dog for you and give it to you. The whole file is given to you.
Whereas in a torrent type of download, the files are broken into chunks. Imagine now after requesting it you have many people with a picture of the same dog, but one person draws the dog’s ears, one draws the face and snout, one draws the arms and the last person draws the legs and tail. The biggest advantage is rather than one person going through the work of drawing the whole picture, many people can work together to deliver your picture. After you receive a part of the dog picture, you are in turn able to copy down that part of the dog for someone else too.
Seeding means being available to copy the picture from (upload). Leeching means requesting parts of a picture from others (download).
“Seeding” is the act of sharing files after completely downloading it while “seeds” are the individuals who do it
“Leeching” is when people don’t share the file with others but still download it, like a leech sucking blood until it’s full.
A torrent file is like an invite to a potluck. You arrive and say “hey guys I’ve arrived, what’s for dinner?” and everyone gives you a bit of the food they have. Eventually you’ve got a full meal and you can eat.
Those people are seeders and are giving you parts of a file to download from their own copy of the file. You’re a leecher who’s downloading the file. The file just begins the process of you connecting to the network and downloading from seeders.
The best part is that, unlike a potluck, you’re just copying the file instead of taking the food.
One neat part that my quick scroll didn’t see mentioned:
The torrent software tries to distribute the rarest piece first, making it less rare and more likely people will be able to get the complete file, even if the seeder drops off.
It’s a special type of direct download, and there’s a reason it’s called torrent.
A torrent beaks a file into smaller pieces, let’s say 10.
10 people want to download the file but you’re the only one who has it.
At first, you send each person one unique piece: person 1 gets piece number 1, person 2 gets piece number 2, etc.
This goes very slowly because you are uploading to 10 people at the same time and those people have to share your limited bandwidth.
Once a person receives their piece, they begin sharing it with the other 10 people. Let’s say person 1 has finished downloading piece 1 from you. They will now begin to upload that to the other people.
So person 2 can now download piece number 1 from you *and* from person 1 at the same time, meaning twice as fast. And they can download piece 3 from person 3 at the same time, so three times as fast, and piece 4 from person 4, etc.
So while you only uploaded the entire file once, slowly, 10 people can now download the file simultaneously 10 times as fast!
That’s why it’s called torrent.
You’d like to buy a book. One option is to go to the bookstore and spend money on it (direct download) but you don’t want to do that.
So you talk to your friend Alberto. Alberto knows everyone, and has a long list of all the people who own this book and are willing to photocopy a page (seeders).
You send a letter to each person, asking for a specific page number (leeching).
They send a letter back with that specific page. Sometimes you are missing a page, or it’s unreadable. That’s ok, you have that list and you can just ask someone else!
Now you have all the pages of the book. Because everyone helped you, you now tell Alberto that you’re willing to help. You give him your address, and you start getting letters asking for pages (becoming a seeder).
That’s fine. You can enjoy your book and help others get pages too.
A torrent is a method of distributing large files in which the file is broken into small pieces and distributed among a network of users. Each user who downloads the file also uploads small pieces of the file to other users. This allows for efficient distribution, as all users are simultaneously uploading and downloading pieces of the file. The process is coordinated by a central “tracker” server, which keeps track of which users have which pieces of the file. A user wanting to download a file using a torrent must first install a “torrent client” on their computer, which communicates with the tracker server and coordinates the downloading and uploading of pieces of the file.
Imagine you live on a street. At the end of the street, is a guy in a red house. He has a 15 page document, detailing information and rules about an upcoming block party. You want this document, as does everyone on the street. But, the problem is that the guy in the red house can only give out a copy of one page at a time, to anyone who comes knocking on his door.
So, you knock on the door. You receive a copy of page 1. You go back home, and drop it on your desk. You then go back to the red house, to request page 2. But, your neighbor is there as well, and he was there before you. So you have to wait a few seconds for him to receive his copy op page 1, before you can request the copy of page 2.
This continues on, and after a while you have 10 pages already. But now, almost everyone in the street is lining up to receive a copy of a page. And the line to wait for the guy in the red house to copy a page is getting long. You now have to wait a solid 15 minutes to request a copy.
Then your neighbor realizes you have page 1 through 10 already. He only has page 1 through 6, and is currently in line to request page 7. He quickly texts his wife, and tells her to ask your wife for a copy of your page 8. It’s not a problem, you have that page anyway, and copying isn’t that much of an issue.
He then realizes the neighbor across the street has pages 12 through 15. So he also sends his son out to get a copy of page 12 from them. You realize his plan, and quickly send out your own kid to grab a copy of page 12 from there as well. And then your other kid to grab a copy of page 14 from the guy down the street with the blue house. Other people in line start doing what you are doing, and start sending out family members to grab copies from other people in the street.
Quickly, the street is abuzz with people running to other houses, grabbing copies of pages that they need, but their neighbor already has. People are still coming to the line at the red house to request certain pages, but it’s a lot less people. Why would they? They can grab copies at other houses as well.
Soon, the guy standing in line in front of you steps out of the line. He only needed a copy of page 3, and his daughter just grabbed a copy of that page from your neighbor. He already has all the pages, so he doesn’t need to ask the guy in the red house for copies anymore. You receive a message from your son. He just grabbed the copy of the last page you needed. You leave the line as well, happy with the result. Instead of lining up for another hour for a new page, you now already have all the pages.
This is how peer to peer (P2P) sharing works. Instead of downloading chunks of a file from one source (and overloading that source with requests), you download it from multiple sources at the same time, who already have a copy themselves. And likewise, you then allow others to download chunks from you, that you have downloaded yourself already.
“Seeding” is the act of sharing chunks you’ve downloaded yourself. This allows other people to downloading from you, instead of downloading it from the source. In the example above, seeding refers to your wife handing out copies of the pages you already have on your desk.
“Leeching” is the opposite: you refuse to share stuff you’ve downloaded. In our example, it would be your wife telling your neighbor’s kid to get lost when they come ask for a certain page you have already.
Oh sweet a torrent file with a list of a bunch of other computers that have what I’m looking for.
Hey, file-holders, I’d like the file. Hey, while you’re at it, I can share whatever part of it I have with whoever is looking for it.
I know I don’t have the whole file yet and I’m just downloading it, so I’m leeching off the goodwill of others. But once I have the whole thing, I’ll seed it to whomever picks up that torrent file
Torrents can be fast on residential asymetrical ISP lines because even though people’s upload speeds are 1:50th your download speed, you can request from 50 different people.
10 people all have the same jigsaw. An 11th wants to create a copy. So the 11th person asks the other 10 to provide whatever pieces they can so they can copy them. It’s just a distributed way of assembling something rather than making a 1:1 clone of something.
Seeding is just the act of making your copy available for others to copy from. Leeching is where you throttle/block other people from copying yours while taking copies from everyone else. You’re leeching off others and not reciprocating.
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