EMule
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- The title of this article is incorrect because of technical limitations. The correct title is eMule.
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In computing, eMule is a peer to peer file sharing application that works with the EDonkey network and has more features than clients on this network. eMule is open source software released under the GNU General Public License. It runs on the Microsoft Windows operating systems and supports 25 languages.
The distinguishing features of eMule are the direct exchange of sources between client nodes, fast recovery of corrupted downloads, and the use of a credit system to reward frequent uploaders. Furthermore eMule transmits data in (Zlib-)compressed form to save bandwidth. Another feature of eMule is the ability to accept "ed2k" links from a web browser and begin downloading the file(s) these links refer to. These links ensure that the file being downloaded is indeed what it says it is and does not contain a virus or spyware. Recently many of the sites which provide these links have been taken offline by authorities due to questionable legality of the links they provide. Duplicate versions of the same file are identified through the use of the MD4 algorithm. The eMule client is a Windows application; its code forms the basis for one of the Linux clients, xMule, and the multiplatform client aMule.
Because eMule is a popular open-source program, hundreds of eMule mods (modifications of the original eMule) have appeared on the Internet.
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History
The eMule project was started by Hendrik Breitkreuz in 13 May 2002 who was dissatisfied by the original EDonkey2000 client. It was continued with help of 7 developers. First publicly available source version of eMule was 0.02 and it was published on Source Forge.net in July 6 2002. First compiled version of eMule was 0.05a and it was released on August 4 2002. The "Credit System" was implemented for a first time on 14 September 2002 in version 0.19a. eMule project website started its work on 8 December 2003. Since the beginning eMule program was downloaded by 85 million people.
Currently project is supported by 16 people: 2 developers, 2 project managers (including the founder Breitkreuz), 3 testers, 9 debug testers. Emule-project web site is supported by 7 webdevelopers and 4 moderators.
Recent events
In recent versions (v0.40+) of eMule was added support for new network called "Kad"(see Kad Network). This network has an implementation of the Kademlia protocol, which does not rely on central servers as the eDonkey network does.
Also added in recent versions were "Unicode Search" (allows searching for files in many languages) and the ability (not supported in Kad Network) to see in server search which files have complete sources (and can therefore be completely downloaded).
In new versions "Bad source list" was added. Program adds IP to this list after one unsuccessful connection. After adding IP to "Bad source list" program treats this IP as a "dead" IP. Unavailable IP is banned for a time period from 15 to 45 minutes. Some users complain that it leads to loss of sources and subsequently slows down download speed.
Other recent additions: ability to run emule from a user account with limited privileges (thus enhancing security), intelligent corruption handling (allowing to pinpoint pieces of data that are corrupted, re-download only corrupted pieces, and eventually ban clients sending corrupted data).
eMule is now considered a stable product, and new versions are not released as often as they used to be - 2-3 months is now a typical time interval between releases.
User / network issues
eMule and other programs on EDonkey network support network in two basic ways:
1) They force the users to share files: Shared files larger than 9500 KB are divided and downloaded in parts, so that a recipient starts to share the parts of the file already downloaded even before the download of the whole file is complete. The recipient is forced to share in this way until the download is complete.
2) They force the users to share their bandwith, thus increasing network's data stream: Official version of eMule forces the users to set their maximum download speed to no more than 4 times their maximum upload speed. This limitation does not apply if maximum upload speed is set to 10K per second or more.
Although there are many mods of eMule, it is hard to find one that doesn't enforce the second feature, which is a part of official eMule policy. Furthermore, attempting to circumvent the uploading feature can possibly slow down user's download process, as he will get worse credits from uploaders. Also, many known "leecher" clients are often banned from the downloading through various means by eMule's mods (banning is not supported in official version).
Large number of eMule users download files larger than 100 MB (complete audio disks or movies) and this leads to huge queues of up to 5000 users. Such queues make eMule very hard to use for exchanging of unpopular small files (such as MP3 with 1-20 sources) and large files (such as albums or videos) from the same user (when a big file has only 1-2 sources).
eMule contains a software algorithm that limit download and upload speeds, so that they do not exceed the limits set by the user.
eMule Limits the filesize to 4290048000 bytes(almost 4GB:32 bit limitation). This is due to the ed2k protocol used.
eMule mods
As a popular open source program, eMule has many variants, usually called mods. Some mods started as a fork of a eMule code, and then continued to develop independently of the official version. A popular mod of this type is eMule Plus. It does not have Kademlia protocol implemented, but proponents of this mod credit it for better GUI and an ability to achieve better download speed than official version. Other mods follow official eMule releases, and make their own releases based on each new release of official version. Often features first debited in a mod later find their way into official version.
Network Status
(data for EDonkey network)
- Number of concurrent users : 4.0 - 5.2 million.
- Number of concurrent shared files: ~600 million.
See also
External links
- eMule project (http://www.emule-project.net)
- eMule on SourceForge (http://sourceforge.net/projects/emule) (SourceForge) - contains archives of past versions of eMule.
- eMule tutorial at AfterDawn (http://www.afterdawn.com/guides/archive/little_emule_tutorial.cfm)
- KademliaSkins.Net (http://www.kademliaskins.net/) - Skins for eMule.ca:EMule
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