uTorrent; commonly abbreviated as "µT" or "uT") is a free, ad-supported, closed sourceBitTorrent client owned by BitTorrent, Inc. It is the most widely used BitTorrent client outside China (whereXunlei is more popular.) It gets the "µ" in its name from the SI prefix "micro-", referring to the program's small memory footprint: the program was designed to use minimal computer resources while offering functionality comparable to larger BitTorrent clients such as Vuze or BitComet. The program has received consistently good reviews for its feature set, performance, stability, and support for older hardware and versions of Windows. The program has been in active development since its first release in 2005. Although originally developed by Ludvig Strigeus, since December 7, 2006, the code is owned and maintained by BitTorrent, Inc. The code has also been employed by BitTorrent, Inc. as the basis for version 6.0 and above of theBitTorrent client, a re-branded version of µTorrent.
µTorrent is available for Microsoft Windows, Mac OS X and Linux. A µTorrent Server is also available for Linux. All versions are written in C++.
History
Early development
Out of general discontent with bloatware, Serge Paquet suggested to Ludvig Strigeus that he should make a smaller and more efficient BitTorrent client. Strigeus began to conceptualize the plans for the program's development, which, at the time, did not include making the client feature-rich. After initially working on it for about a month during the last quarter of 2004 (the first build is dated October 17, 2004), mostly during his free time before and after work, Strigeus ceased coding µTorrent for a year. He resumed work on September 15, 2005, and three days later, the first public release (version 1.1 beta) was made available as freeware, and began generating feedback.
Features present in µTorrent include:
• Streaming of video torrents
• Teredo tunneling / IPv6 support
• Micro Transport Protocol (µTP) preliminary support as of 1.8.2 with full-support added in 2.0
• UPnP support for all versions of Windows, without needing Windows XP's UPnP framework
• Protocol encryption (PE)
• Peer exchange (PEX) with other BitTorrent clients:
o libtorrent and clients based on it like Deluge have full µTorrent PEX support
o Transmission and clients based on libTransmission have full µTorrent PEX support
o KTorrent has full µTorrent PEX support as of 2.1 RC1
o Vuze, formerly Azureus, has full support as of version 3.0.4.3
• RSS ("broadcatching")
• "Trackerless" BitTorrent support using DHT, compatible with the original BitTorrent client and BitComet
• User configurable intelligent disk caching system
• Full proxy server support
• HTTPS tracker support
• Configurable bandwidth scheduler
• Localized for 66 languages.
• Initial seeding of torrents
• Customizable search bar & user interface design.
• Configuration settings and temporary files are stored in a single directory, allowing portable use
• WebUI: A plugin currently in beta testing that allows µTorrent running on one computer to be controlled from another computer, either across the internet or on a LAN, using a Web browser
o A new web user interface, codenamed Falcon, is in development. It supports encrypted sessions and the ability of going through firewalls without port forwarding, while being more complete and easier to start using than its predecessor.
• Embedded Tracker: a simple tracker designed for seeding torrents, lacking a web interface or list of hosted torrents. It is not designed for secure or large-scale application.
• Quick-resumes interrupted transfers
• Versions of µTorrent up to 1.8.5 build 17091 can use as little as 14 MB of RAM running on a 486 processor on Windows 95. Unicodesupport for Windows 95/98/ME, avoiding use of the Microsoft Layer for Unicode which is several times larger than µTorrent. As of March, 2011, newer versions required at least Windows XP or newer. Currently µTorrent requires at least Windows XP.
• Two "easter egg" hidden features in the About subsection of Help: clicking the µTorrent logo plays a Deep Note-like sound effect, and typing the letter "t" starts a Tetris-like game called μTris, which in 2008 was selected as #1 of the "Top 10 Software Easter Eggs" byLifeHacker.
Size
µTorrent is shipped as a single stand-alone compressed executable file, installed at first run. Recent versions have included the ability to install themselves on first run. Small executable size is achieved by avoiding the use of many libraries, notably the C++ standard library and stream facilities, and creating substitutes written specifically for the program. The executable is then compressed to roughly half of its compiled and linked size using UPX.
Operating system supports
µTorrent is available for Microsoft Windows, Mac OS X and Linux.
The first test version for Mac OS X, running on Mac OS X 10.5, was released on 27 November 2008.
On September 2, 2010, the native Linux version of µTorrent Server was released. Firon, an administrator of the µTorrent community forum, said that they had been working on this project for a few months prior to the release as it was the most requested feature for some time. This release is intended for users who are seeking a fast command-line interface based BitTorrent client with a remote web-based management. They also mentioned that a full featured client with a GUI is a work in progress. He also said: "This is a native Linux port and is known to work on Ubuntu 9.10+, Debian 5+ and Fedora 12+. Others may work, but they are not officially supported. Kernel 2.6.13 or newer required. 64-bit host systems currently have some problems, so 32-bit only for now. For trackers who whitelist, the user agent is "uTorrent/300B(build#)(server)". The peerid is identical to the Windows 3.0 client. They share version numbers because of a common codebase.
Languages
The software is available in the following languages:
Arabic Chinese (Simplified) Gaeilge Kazakh Marathi Russian Thai
Awadh Chinese (Traditional) Georgian Khmer Mongolian Serbian (Cyrillic) Turkish
Armenian Croatian Greek Korean Nepali Serbian (Latin) Ukrainian
Azerbaijani Czech Hebrew Kurdish Norwegian Sinhala Urdu
Basque Danish Hungarian Kyrgyz Norwegian Nynorsk Slovak Vietnamese
Belarusian Dutch Icelandic Latvian Persian Slovenian Welsh
Bengali Esperanto Indonesian Lithuanian Polish Spanish
Bosnian Estonian Italian Macedonian Portuguese (Brazil) Swedish
Bulgarian Finnish Japanese Malayalam Portuguese (Portugal) Taiwan
Catalan French Kannada Malay Romanian Tamil