in computer networks, to download means to receive data to a Local System from a Remote System, or to initiate such a data transfer. Examples of a remote system from which a download might be performed include a webserver, FTP server, email server, or other similar systems. A download can mean either any file that is offered for downloading or that has been downloaded, or the process of receiving such a file. This download can also be done through ftp servers as often many of the files available on a website to be downloaded are also present on ftp severs.
The inverse operation, uploading, can refer to the sending of data from a local system to a remote system such as a server or another client with the intent that the remote system should store a copy of the data being transferred, or the initiation of such a process. The words first came into popular usage among computer users with the increased popularity of Bulletin Board Systems (BBSs), facilitated by the widespread distribution and implementation of dial-up access the in the 1970s.
The use of the terms uploading and downloading often imply that the data sent or received is to be stored permanently, or at least stored more than temporarily. In contrast, the term downloading is distinguished from the related concept of streaming, which indicates the receiving of data that is used near immediately as it is received, while the transmission is still in progress and which may not be stored long-term, whereas in a process described using the term downloading, this would imply that the data is only usable when it has been received in its entirety.
Increasingly, websites that offer streaming media or media displayed in-browser, such as YouTube, and which place restrictions on the ability of users to save these materials to their computers after they have been received, say that downloading is not permitted. In this context, "download" implies specifically "receive and save" instead of simply "receive".
source : http://en.wikipedia.org/wiki/Download
The inverse operation, uploading, can refer to the sending of data from a local system to a remote system such as a server or another client with the intent that the remote system should store a copy of the data being transferred, or the initiation of such a process. The words first came into popular usage among computer users with the increased popularity of Bulletin Board Systems (BBSs), facilitated by the widespread distribution and implementation of dial-up access the in the 1970s.
The use of the terms uploading and downloading often imply that the data sent or received is to be stored permanently, or at least stored more than temporarily. In contrast, the term downloading is distinguished from the related concept of streaming, which indicates the receiving of data that is used near immediately as it is received, while the transmission is still in progress and which may not be stored long-term, whereas in a process described using the term downloading, this would imply that the data is only usable when it has been received in its entirety.
Increasingly, websites that offer streaming media or media displayed in-browser, such as YouTube, and which place restrictions on the ability of users to save these materials to their computers after they have been received, say that downloading is not permitted. In this context, "download" implies specifically "receive and save" instead of simply "receive".
source : http://en.wikipedia.org/wiki/Download
