BitComet

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BitComet
BitComet logo.svg
BitComet 0.94.png
BitComet client version 0.94 running on Windows Vista
Developer(s) BitComet Development Group
Initial release August 6, 2003
Stable release 1.16 / 2009-11-10; 20 days ago
Written in C++
Operating system Windows 98/Me/2000/XP/2003/Vista/7
Available in 52 languages
Type BitTorrent client
License Proprietary freeware
Website http://www.bitcomet.com

BitComet (originally named SimpleBT client from versions 0.11 to 0.37) is a controversial[1] cross-protocol BitTorrent, HTTP and FTP client written in C++ for Microsoft Windows and available in 52 different languages.[1] Its first public release was version 0.28. The current BitComet logo has been used since version 0.50.[2]

Contents

[edit] Features

The BitComet program is a multi-threaded multi-protocol hybrid download manager and BitTorrent Peer-to-peer (P2P) file-sharing application. It supports simultaneous download tasks. To complete a particular download, it can draw parts of files from many sources across different P2P and Client-server protocols.

BitComet's chief features include an embedded Internet Explorer window for the purpose of allowing users to search for torrents within the program. Along with the features typical of contemporary BitTorrent clients, it supports UPnP gateway configuration, bandwidth scheduling, Webseeding, selecting downloads inside a torrent package, and NAT traversal.[3]

When downloading, BitComet prioritizes the first and last portions of media files so that files may be previewed before they are completely downloaded. BitComet also allows users to share their torrent files on a searchable P2P network. BitComet uses the Kademlia (mainline) DHT to operate even when the tracker is offline. BitComet is capable of downloading files over HTTP and FTP as well as bittorrent, and it includes download plugins for Firefox, Internet Explorer, and Maxthon.[3]

An optional plugin is available to connect to the eD2K network. The plugin is a modified version of the GPL eMule program. When installed, it connects automatically to a server.[4]

BitComet FLV Player version 1.3

The software includes an application to play Flash Video files (.flv and .swf files).[5]

[edit] Optional standalone software

BitComet.com offers a BitTorrent tracker available for download from the official site.[6] The FLV player program can also be downloaded separately and used independently of the BitComet software.

[edit] Search engine

The search site is google.atcomet.net

[edit] Controversy and criticism

[edit] Hash reporting

Since version 0.86 BitComet includes discussion and stat-tracking features which send information about torrents to the Bitcomet.com servers, including the torrent hash.[7][verification needed]

[edit] DHT exploit

During version 0.60, BitComet received bad publicity because its implementation of the DHT feature, which was new at the time, could be exploited to not respect the private flag of a tracker. This allowed users to avoid download and upload ratio restrictions, which are common on private trackers. Some private trackers responded to this by blacklisting version 0.60.[8] BitComet developer RnySmile reverted the client back to version 0.59 in response to the blacklisting.[9]

The DHT exploit was fixed in version 0.61.[10][11]

[edit] Padding files

Starting with version 0.85 (Early 2007), BitComet added an option to its torrent maker that ensures that no two data files in a multi-file torrent occupy the same BitTorrent "piece", which has caused problems with partial-torrent downloads in all bittorrent clients. To accomplish this, BitComet fills the remainder of each last "piece" with an empty "padding" file. While these small and harmless files are transparent to the BitComet user, they can be an annoyance to users of other clients who must deal with them both during and after the download. Other clients could choose to hide these files, as BitComet advises, but they choose not to.[12] Creation of padding files was enabled by default in version 0.85, and disabled by default in version 0.86 onward.[verification needed]

[edit] Validity of criticism

In July 2007, Robb Topolski, a self-described “networking and protocol expert”[2] conducted an independent analysis of most accusations leveled against BitComet including the DHT Exploit and Super-seeding controversies mentioned above. He found all but one of the claims to be false or unverifiable. He found that BitComet is not detrimental or malicious to the download or upload speeds of a BitTorrent swarm or the tracker.[13]

The one claim he verified as partially correct was that, "BitComet is a poor peer due to no upload slot control; upload bandwidth is stretched too thin". Topolski's tests indicated that BitComet does lack upload slot control, but only when BitComet is initially seeding a torrent—that is, when BitComet is the only seeding peer in a swarm, it tends to seed less efficiently than the two other clients he tested. Topolski asserts that when BitComet is not the only seeding peer in the swarm, or when it is a non-seeding peer, upload slot control is managed exceptionally well.[14]

[edit] Torrent file format

According to the official BitTorrent specification, 'All strings in a .torrent file that contains text must be UTF-8 encoded'. When generating torrents on (e.g.) Chinese or Japanese (non-Latin character) systems, BitComet encodes the files' names and paths using the Windows Chinese/Japanese code page, and stores a UTF-8 version in a non-standard attribute.

BitComet-generated torrents on non-Latin systems therefore technically violate the letter of the specification, which has no provision for filenames using non-UTF8 characters and effectively discriminates against those languages. Since there is no specification on the matter, other clients may incorporate other solutions, or ignore the problem, and so might not be able to read each others' file names correctly. [15] [16]

[edit] See also

[edit] References

  1. ^ "Supported Languages in BitComet". 2009-03-11. http://www.bitcomet.com/. Retrieved 2008-05-13. 
  2. ^ "BitComet BitTorrent Client". 2006-05-10. http://www.quartermeg.com/bitcomet-review.htm. Retrieved 2008-05-13. 
  3. ^ a b "What is BitComet?". 2008-05-07. http://www.bitcomet.com/index.htm. Retrieved 2008-05-13. 
  4. ^ "eMule Plugin for BitComet". 2008-03-27. http://www.bitcomet.com/doc/plugin-emule.htm. Retrieved 2008-05-13. 
  5. ^ "BitComet FLV Player (Flash Video Player)". 2008-03-27. http://www.bitcomet.com/tools/flvplayer/index.htm. Retrieved 2008-05-13. 
  6. ^ "BitComet Tracker". 2008-03-27. http://www.bitcomet.com/tools/tracker/index.htm. Retrieved 2008-05-13. 
  7. ^ BitComet.com (2008). "BitComet reporting bug?". http://forums.bitcomet.com/index.php?showtopic=12789405. Retrieved 2008-05-15. 
  8. ^ Thomas Mennecke (2005). "BitComet Banned". http://www.slyck.com/story1021.html. Retrieved 2007-01-15. 
  9. ^ Thomas Mennecke (2005). "BitComet Reverts to Version .59". http://www.slyck.com/story1030.html. Retrieved 2007-01-15. 
  10. ^ Thomas Mennecke (2006). "BitComet .62 and You". http://www.slyck.com/story1094.html. Retrieved 2006-12-03. 
  11. ^ Thomas Mennecke (2006). "BitComet .64 Released". http://www.slyck.com/story1152.html. Retrieved 2006-01-15. 
  12. ^ Ernesto (2007-08-23). "BitComet Pollutes BitTorrent with Junk Data". TorrentFreak. http://torrentfreak.com/bitcomet-pollutes-bittorrent-with-junk-data/. Retrieved August 24, 2007. 
  13. ^ Rob Topolski (2007-08-02). "STUDY: 'Examining the Myths and Facts Concerning BitComet Behavior'". ZeroPaid. http://www.zeropaid.com/news/8945/STUDY:+'Examining+the+Myths+and+Facts+Concerning+BitComet+Behavior'. Retrieved 2008-02-07. "[Regarding the claim that] BitComet seems to favor uploading to other BitComet clients, even when getting faster download speeds from other clients ... In dozens of observed sessions using BitComet, I see no such preference being given to BitComet peers. ... BitComet is a worthy download client, providing some advantageous features not found in any other current BitTorrent client. Some of these features are confusing and are poorly implemented, but they are not detrimental to a BitTorrent swarm, nor do they take unfair advantage." 
  14. ^ Topoloski. “If the BitComet user is the initial seeder, that user will take more time and bandwidth to seed a torrent than any other BitTorrent client I have ever used. (Tests: BitComet 200% to 255%, MainLine 145% to 175%, uTorrent with Super-Seeding 105% to 115%). However, when BitComet is a non-seeding peer, it has exceptionally intelligent slot control. BitComet adjusts the speed of each upload slot individually, providing more upload bandwidth to peers that reciprocate with more upload bandwidth of their own. ... BitComet is an exceptionally poor upload client and should be avoided if the user will be the initial uploader to a swarm. ... This is not an issue if the BitComet user is a seeder in an already-seeded swarm.”
  15. ^ Bram Cohen. "The BitTorrent Protocol Specification". http://www.bittorrent.org/beps/bep_0003.html. Retrieved 2009-08-26. "The name key maps to a UTF-8 encoded string ... path - A list of UTF-8 encoded strings ... All strings in a .torrent file that contains text must be UTF-8 encoded." 
  16. ^ BitComet Support Team. "BitComet - Torrent File Format". http://blog.bitcomet.com/bitcomet/post_413/. Retrieved 2009-08-26. "In BitComet v0.58 or before, the string is encoded using MSCB (user's code page), and a ".utf-8" key is added for UTF-8 encoded string. In v0.59, the default encoding is changed to UTF-8 if the user's code page is neither Chinese nor Japanese." 

[edit] External links

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