Why uploading and downloading a file is required explain with example?

Uploading means data is being sent from your computer to the Internet.

Examples of uploading include sending email, posting photos on a social media site and using your webcam. Even clicking on a link on a web page sends a tiny data upload.

Downloading means your computer is receiving data from the Internet.

Examples of downloading include opening a web page, receiving email, purchasing music files and watching online videos.

You've probably heard the terms "upload" and "download" many times, but what do these terms actually mean? What does it mean to upload a file to a website or download something from the web? What's the difference between a download and an upload?

These are basic terms that any web user should understand. They come into play when following some directions, troubleshooting network issues, choosing your internet speed, and more.

Below, we'll go over what these terms mean, as well as common peripheral terms and information that will help you have a firmer grasp of these common online processes. 

In the context of the web, upload = send. You can think of it like loading the data "upward" to the cloud/internet.

When you upload something to a website, or another user's computer, or a network location, etc., you're sending data from your device to the other device. Files can be uploaded to a server, such as a website, or directly to another device, like when using a file transfer utility.

For example, if you upload an image to Facebook, you're sending the picture from your device to the Facebook website. The file started with you and ended up somewhere else, so it's considered an upload from your perspective.

This is true for any transfer like this, no matter the file type or where it's going. You can upload documents to your teacher via email, upload a video to YouTube, upload music to your online music collection, etc.

In opposition to upload, download = save. You're taking data from elsewhere and putting it onto your device, essentially bringing it "down" from the internet.

Downloading something from the web means that you're transferring data from the other location to your own device, whether it be your phone, computer, tablet, smartwatch, etc.

All sorts of information can be downloaded from the web: books, movies, software, etc. For example, you can download movies to your phone to watch while you're on the go, which means that the actual data that makes up the movie is transferred from the site you got it from and saved to your phone, making it locally available.

Considering that an upload is sending data, and a download is saving data, you might have caught on already that this goes on all the time when you use the web.

Open your web browser and go to Google.com, and you immediately requested the site (uploading tiny bits of data in the process) and got the search engine in return (it downloaded the correct web page to your browser).

Here's another example: when you browse YouTube for music videos, each search term you enter is sending tiny bits of data to the site to request the video you're looking for. Each of those requests you send are uploads, since they started on your device and ended up on YouTube's end. When the results are understood by YouTube and sent back to you as web pages, those pages are being downloaded to your device for you to see.

For a more concrete example, think about an email. You're uploading the pictures to an email server when you send someone photos over an email. If you save picture attachments from someone who emailed you, you're downloading them to your device. Another way to see it: you upload the images so that the recipient can view them, and when they save them, they're downloading them.

Uploads and downloads happen all the time in the background. You don't usually need to understand when something is uploading or downloading or what they really refer to, but knowing how they differ is important in some situations.

For example, if a website tells you to upload your resume using their online form, but you don't know if that means to save something to your computer or send them a file, it can get confusing and delay the overall process you're trying hard to finish.

Or, maybe you're buying a home internet plan, and you see one advertised as offering 50 Mbps download speeds and another with 20 Mbps upload speeds. Most people don't need a fast upload speed unless they're often sending large amounts of data over the internet. However, not knowing the difference between upload and download might leave you paying for way more than you require, or paying a smaller amount for speeds too slow for what you need.

Since the speed at which you can download things from the internet is determined by what you're paying your ISP for, some people opt to stream data versus download it. They're similar, but not technically the same, and there are benefits of both.

For example, there are movie streaming sites that let you watch movies online instead of download them, and web apps that can be used in a browser instead of saved to your device.

Downloading is useful if you want the entire file for offline use, like if you plan to watch movies, edit documents, view photos, or listen to music without an internet connection. The entire file is saved on your device since you downloaded it, but to use it, you have to wait for the whole download to finish.

Streaming, on the other hand, is useful if you want to use the file before it's finished downloading. You can stream Netflix shows on your tablet without needing to download the full episode first. However, the file isn't usable offline because it isn't stored for future use.

The terms download and upload are usually reserved for transfers that take place between a local device and something else on the internet.

For example, we don't normally say we're "uploading" an image to flash drive when we copy it from a computer, or that we're "downloading" a video when they're just being copied off of the flash drive. Some people do, however, use these terms in those circumstances, but they're really just referring to the act of file copying.

There are network protocols that support data uploads and downloads. One is FTP, which utilizes FTP servers and clients to send and receive data between devices. Another is HTTP, which is the protocol used when you send and receive data through your web browser.

You may notice that your home internet download and upload speeds aren't the same. The short answer for why your download speed is faster than your upload speed is due to demand.

This speed difference is usually fine for most people, since the average internet user consumes more data than they share, meaning there's no need to support the same speeds for uploads. The exception is business customers that deliver data, including web servers like the ones that host the websites you visit. Fast upload speeds are typically necessary so that you, the user of the company's services, can download at a decent speed. There's no need to give a home user ultra-fast upload speeds since they aren't delivering files to customers, but instead they are the customer, and so quicker downloads are prioritized.