Downloads/Uploads – How the data comes from the internet and disappears again

Downloads and also uploads are an essential, if not the essential process on the Internet. Anyone who has ever visited an Internet site has "downloaded" the website on their own computer to view it.

But just because this process happens so easily in the background that does not mean that he is directly understood. That's why I want to try to explain the whole thing in order to subsequently show how to deliberately download a specific file from the Internet.

Hints for our lovely english readers: Basically, many of the articles on are translations from the original german articles. Therefore, it may happen here and there that some illustrations are not available in english and that some translations are weird/strange/full of mistakes or generally totaly wrong. So if you find some obvious (or also not obvious) mistakes don't hesitate to leave us a hint about that in the comment section. 
Also please don't get confused, that instead of a "dot" often a "comma" is used as decimal separator. 🙂

Networking on the Internet:

To explain the whole thing, you have to explain a bit about the networking of individual computers on the Internet. On the Internet, all PCs are connected. Many of them do so by detours but ultimately it is possible with any computer connected to the Internet to "reach" any other computer connected to the Internet in the world, ie to communicate with it.

These computers can roughly be divided into two groups: on one side there are the servers (server = "servant" / "bidder") and on the other side there are the clients (client = "user" / "customer") , you can tell by the terms of the two groups: The servers offer something and the clients use something.

Server vs client

For example, the computer you are currently sitting on is very likely a client. You visit websites and use content from the internet. But where does this content come from?

And that's where the servers come in. A server, in a simplified sense, is a computer that waits the whole day for it to receive a request from somewhere on the Internet from a client. For example, if you type in an Internet address in your browser and press "Enter" then this is a request to the server behind this Internet address.

This question might sound like "Hey dear server, I would like to visit the website stored on your server.".
The server will respond in most cases: "Hey dear client, no problem, get ready then this is the website...".


And here begins a download! The server will now start a copying process of the website to your computer. Your computer also starts to copy the files from the server. That's why this process is called "Download".

Only after you have downloaded this website will be displayed in your browser. Therefore, after typing the Internet address and pressing the Enter key, you also have a small delay until the web page is displayed.

Especially the users of slow Internet connections will know this. This delay is the time it takes to copy the web page to your computer.

The difference to a "conscious" download of a specific file when visiting websites, however, is that these websites are not (normally) permanently stored on your computer. These files of the corresponding website are usually only temporarily stored in a cache until the browser either by itself or you empties this cache again.

Start "conscious" downloads

In order to download a certain file completely "consciously" you would have to proceed a little differently. This can be explained easiest with an example:
Suppose you are interested in downloading the browser "Firefox". After a short Google search you will find the following link:

There you can see in the upper (red marked) area already, the big "Download Firefox" button.
So you click on the link and you will be redirected to the actual download page.

This window looks a bit different depending on which browser you use. That's why I've added an example of the most popular browsers Firefox, Opera, Chrome and Microsoft Edge.

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Although the dialog windows are different in appearance, they are basically all the same.
You as a user should now decide if you want the file, and if so, where you want to download it. The only exception: The browser "Chrome" downloads the files without dialog box and informs you then only at the bottom of the fact that a new file has been downloaded.
Since you want to find the files after the download, of course, you must now remember where you store the file on your computer.
Windows now also supplies a standard folder. If the settings have not been changed, all downloads are automatically saved in the "Downloads" folder.

In order to save the file that you want to download in the default folder downloads you have to proceed in the respective browsers different but similar. The following photos show (through a red marked area) what you have to click.

Depending on the size of the file and the speed of your Internet connection or the connection between your computer and the server, the download will take a while. For small files, however, it is usually so quickly over that you do not really notice much of the download process.

When the download is complete you can then call the downloaded file from the browser.

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Security warning

In many cases there is a security warning before the file is executed. This is no cause for alarm. It's a reminder that this file to start is a file from the internet and that you should only run it if you know "where it's from". To do this, you will also be shown in the dialogue window of the security warning where the file is stored exactly and from which "manufacturer" (in this case the "Mozilla Corporation") it comes from. Since you've just downloaded this file knowingly from a trusted source, you can do it without a pang of conscience. For this click once on "Download"(in Picture "Run") and your file or in this case program should be executed.

And that was about it. You have just successfully downloaded and run a file. 🙂

OK, but what about uploads? Uploads are basically the same as downloads just the other way round. Instead of downloading files down, ie copying them from the server to the client (your computer), you now copy data from your computer to the server.

Such an upload possibility you find for example in your web email client when it comes to an email with attachment to send
In order to be able to send an e-mail with an attachment, the attachment will first be downloaded from your computer to the server. As soon as you send the e-mail, the e-mail will be sent by the server with the attachment already loaded on the server.
In principle, you control the server via the web email client and tell it "Here is an e-mail with this text and the attachment, please send it to this e-mail address."
This can best be explained by an example. As mentioned above, you need uploads when sending an e-mail with attachment. I have explained this here: send emails with attachment via

Of course, there are other places on the Internet where you can encounter an upload.
With this basic knowledge about downloads and uploads, you will now notice more and more situations on the internet where you are downloading or uploading.

Have fun with the project

I hope everything worked as described. If not or you have any other questions or suggestions, please let me know in the comments. Also, ideas for new projects are always welcome. 🙂

P.S. Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you appreciate that I share this information with you, I would be happy about a small donation to the coffee box. 🙂

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