Downloading a file is not the same as “installing” it. When you download a file, it is simply copied from a remote computer to the one you are working on. The download ends when the full file is now stored on your hard drive. However, the program is not yet ready to use - installation is required for that.
Peer-to-peer (P2P) downloads use special clients and protocols to send and receive files without a central host. Often, today, this installation program is a small program that returns to the web and downloads the files for the actual installation. The file you downloaded in most cases is a program that performs the installation, not the program itself. Hypertext Transfer Protocol (HTTP) downloads use the same protocol as website browsing downloads to send file data.
Download speed is a measure of the amount of data that can be transferred from an arbitrary Internet location to a user's device in one second. An ISP will announce the fastest theoretical download speed possible, but there are many factors that can affect the download speed in the real world. When downloading a file, users have the option to click “execute” instead of “save”. When transferring a file to a device, for example, for music or video, users can have the option to download, cache, or stream it.
Businesses can benefit from having the same upload speed as their downloads; this is called having a symmetrical Internet connection. This is because, for most people, they need to download much more data than they need to upload, which is why ISPs prioritize downloads. When they download it, users make a copy of the data from what is on the central computer, called the server. However, smaller companies may only have a server that is easily overwhelmed by many people trying to download something, and the resulting download is slow. In general, when you download something you make a permanent copy of it; when you cache something you make a temporary copy; and when you stream something you only copy it as it is used.
