eMule

www.emule-project.net

eMule is a free peer to peer (P2P) file sharing application first released in 2002. Since then, the program has been downloaded over 185 million times. The distinguishing features of eMule are:

• free of any adware, spyware or malware.
• the use of a credit system to reward frequent uploaders
• clients use several networks to create one reliable network. (ED2K, Source Exchange, Kad).
• the direct exchange of sources between client nodes.
• a wide range of search possibilities which include: Servers (Local, and Global), web based (Jigle, and Filedonkey), and Kad.
• complex Boolean searches available to make searches more flexible
• each file is checked for corruptions whilst downloading to ensure an error free file.
• fast recovery of any corrupted downloads.
• preview function to allow users to look at files before they are completed.
• built in IRC client to allow users to chat with other downloaders and chatters around the globe.

All files are given a hash value that depends on the file's contents, but not its filename. This allows each user to find all sources to a particular file no matter what file name each user has given the file. Files are then broken into 'chunks' of 9.28 MB and downloaded in parts, so that a recipient shares the fragments of the file already downloaded before the download of the whole file is complete.

eMule uses a credit system to reward users that contribute to the network by uploading to other clients. The more a user uploads, the higher their rating and the less time they have to spend queuing for an upload slot. For example, a peer with rating of x1 would have to wait twice as long to get an upload slot than a peer with a rating of x2.