و هي شبكة خاصة تكون عبر مواقع خاصة يشارك فيها شخص ما بملف ( فيلم - برنامج - لعبة - نظام تشغيل - ... إلخ)
و يكون ذلك بعمل ما يشبه مفتاح للملف الموجود على جهازه الشخصي، هذا الملف الصغير المحتوي على بيانات تجميع الملف الأصلي المراد تحميله يسمى تورنت Torrent.
يكون الشخص الممتلك للملف هو Seed أو Seeder بمعنى البذرة أو النواة..
و يكون الأشخاص الراغبين في تحميل الملف منه هم Peers أو Leechers أي المتتبعين له...
عند تحميلك ملف التورنت للملف الذي تريد تحميله من مواقع مشاركة التورنت، و ببرنامج التورنت، تجد أن الأشخاص Seeders الذين يمتلكون الملف كاملاً هم من يمتلكونه بنسبة كاملة (100%)، بينما تجد الأشخاص Peers مثلك يمتلكون الملف بنسب متفاوتة من 0% و حتى 99.9%
فإذا اكتمل الملف لدى أي منهم تحول من Peer إلى Seed لذلك الملف.
إذاً يعتمد تحميل الملف التورنت على الأشياء التالية..
1- المواقع أو التراكات الموضوع عليها ملف المشاركة الصغير الذي يحتوي على معلومات الملف الأصلي (التورنت).
2- عدد الأشخاص Seeders الذين يمتلكون الملف كاملاً، و كذلك عدد الأشخاص Peers الذين يسحبون الملف.
3- سرعة اتصال الإنترنت لديك أنت كمستخدم.
4- البرنامج الذي تستخدمه للمشاركة في شبكة P2P لتحميل الملف الأصلي، و هي برامج كثيرة منها U torrent, Bitspirit,Bitcommet,... Etc.
مع ذلك تبقى في معظم الأحيان سرعة التحميل منخفضة، و قد تصل لعُشر السرعة الأصلية عندك، مما يجعل تحميل الملف يستغرق وقتاً كبيراً للغاية.
و لحل تلك المشكلة ظهرت مجموعة من المواقع التي يمكنها أن تقوم بسحب الملف الأصلي بطريقة P2P، بسرعة كبيرة للغاية (تتناسب مع إتاحة الملف و عدد Seeders و Peers الموجودين له)، لتوفر لك رابط مباشر تماماً يمكنك التحميل منه بالطريقة العادية و بالبرامج التي تضمن لك الحفاظ على السرعة مثل Internet Download Manager, Download Accelerator و غيرها...
كان أحد أشهر هذه المواقع في التحويل هو موقع Torrific، و الذي اختفى فجأة لأسباب اختلف الناس بشأنها..
و لكن حلت محله عدة بدائل أهمها كان موقع Zbigz، و هو موقع يتيح التسجيل فيه مجاناً لتحويل ملفات التورنت إلى ملفات عادية بمحدودية، أو التسجيل المدفوع لتحويل الملفات بلا حدود...
يلي الموقع المذكور، موقع Furk.net الذي يؤدي الوظيفة نفسها لتحويل ملفات التورنت إلى روابط تحميل مباشرة
فيديو يوضح كيفية عمل ذلك
و يمكننا تعديد تلك المواقع بالترتيب كما يلي، و إضافة المزيد كلما أمكن ذلك:
1- موقع Zbigz
2- موقع Furk.net
3- موقع Bitlet
4- موقع Quick torrent
5- موقع Torrent2exe
6- موقع Putshare
7- موقع Torrent handler
BitTorrent is a peer-to-peer file sharing protocol used for distributing large amounts of data over the Internet. BitTorrent is one of the most common protocols for transferring large files and it has been estimated that peer-to-peer networks collectively have accounted for roughly 43% to 70% of all Internet traffic (depending on geographical location) as of February 2009.[1]
Programmer Bram Cohen designed the protocol in April 2001 and released the first available version on July 2, 2001.[2] It is now maintained by Cohen's company, BitTorrent, Inc. Currently, numerous BitTorrent clients are available for a variety of computing platforms.
As of January 2012, BitTorrent has 150 million active users according to BitTorrent, Inc. Based on this the total number of monthly BitTorrent users can be estimated at more than a quarter billion.[3] At any given instant BitTorrent has, on average, more active users than YouTube and Facebook combined. (This refers to the number of active users at any instant and not to the total number of unique users.)[4][5][dubious ] BitTorrent is widely used to transfer Files. More than 200,000 people have been sued since 2010 for transferring copyrighted materials on the BitTorrent network
Description
The BitTorrent protocol can be used to reduce the server and network impact of distributing large files. Rather than downloading a file from a single source server, the BitTorrent protocol allows users to join a "swarm" of hosts to download and upload from each other simultaneously. The protocol is an alternative to the older single source, multiple mirror sources technique for distributing data, and can work over networks with lower bandwidth so many small computers, like mobile phones, are able to efficiently distribute files to many recipients.A user who wants to upload a file first creates a small torrent descriptor file that they distribute by conventional means (web, email, etc.). They then make the file itself available through a BitTorrent node acting as a seed. Those with the torrent descriptor file can give it to their own BitTorrent nodes which, acting as peers or leechers, download it by connecting to the seed and/or other peers.
The file being distributed is divided into segments called pieces. As each peer receives a new piece of the file it becomes a source (of that piece) for other peers, relieving the original seed from having to send that piece to every computer or user wishing a copy. With BitTorrent, the task of distributing the file is shared by those who want it; it is entirely possible for the seed to send only a single copy of the file itself and eventually distribute to an unlimited number of peers.
Each piece is protected by a cryptographic hash contained in the torrent descriptor.[7] This ensures that any modification of the piece can be reliably detected, and thus prevents both accidental and malicious modifications of any of the pieces received at other nodes. If a node starts with an authentic copy of the torrent descriptor, it can verify the authenticity of the entire file it receives.
Pieces are typically downloaded non-sequentially and are rearranged into the correct order by the BitTorrent Client, which monitors which pieces it has, can upload to other peers and which it needs. Pieces are of the same size throughout a single download (for example a 10 MB file may be transmitted as ten 1 MB Pieces or as forty 256 KB Pieces). Due to the nature of this approach, the download of any file can be halted at any time and be resumed at a later date, without the loss of previously downloaded information, which in turn makes BitTorrent particularly useful in the transfer of larger files. This also enables the client to seek out readily available pieces and download them immediately, rather than halting the download and waiting for the next (and possibly unavailable) piece in line, which typically reduces the overall length of the download.
When a peer completely downloads a file, it becomes an additional seed. This eventual shift from peers to seeders determines the overall "health" of the file (as determined by the number of times a file is available in its complete form).
The distributed nature of BitTorrent can lead to a flood like spreading of a file throughout many peer computer nodes. As more peers join the swarm, the likelihood of a complete successful download by any particular node increases. Relative to traditional Internet distribution schemes, this permits a significant reduction in the original distributor's hardware and bandwidth resource costs.
Distributed downloading protocols in general provide redundancy against system problems, reduces dependence on the original distributor[8] and provides sources for the file which are generally transient and therefore harder to trace by those who would block distribution compared to the situation provided by limiting availability of the file to a fixed host machine (or even several).
One such example of BitTorrent being used to reduce the distribution cost of file transmission is in the BOINC Client-Server system. If a BOINC distributed computing application needs to be updated (or merely sent to a user) it can be done so with little impact on the BOINC Server.
Operation
To share a file or group of files, a peer first creates a small file called a "torrent" (e.g. MyFile.torrent). This file contains metadata about the files to be shared and about the tracker, the computer that coordinates the file distribution. Peers that want to download the file must first obtain a torrent file for it and connect to the specified tracker, which tells them from which other peers to download the pieces of the file.
Though both ultimately transfer files over a network, a BitTorrent download differs from a classic download (as is typical with an HTTP or FTP request, for example) in several fundamental ways:
- BitTorrent makes many small data requests over different TCP connections to different machines, while classic downloading is typically made via a single TCP connection to a single machine.
- BitTorrent downloads in a random or in a "rarest-first"[9] approach that ensures high availability, while classic downloads are sequential.
In general, BitTorrent's non-contiguous download methods have prevented it from supporting "progressive downloads" or "streaming playback". However, comments made by Bram Cohen in January 2007 suggest that streaming torrent downloads will soon be commonplace and ad supported streaming appears to be the result of those comments. In January 2011 Cohen demonstrated an early version of BitTorrent streaming, saying the feature was projected to be available by summer 2011.[9]
Creating and publishing torrents
The peer distributing a data file treats the file as a number of identically sized pieces, usually with byte sizes of a power of 2, and typically between 32 kB and 16 MB each. The peer creates a hash for each piece, using the SHA-1 hash function, and records it in the torrent file. Pieces with sizes greater than 512 kB will reduce the size of a torrent file for a very large payload, but is claimed to reduce the efficiency of the protocol.[10] When another peer later receives a particular piece, the hash of the piece is compared to the recorded hash to test that the piece is error-free.[11] Peers that provide a complete file are called seeders, and the peer providing the initial copy is called the initial seeder.The exact information contained in the torrent file depends on the version of the BitTorrent protocol. By convention, the name of a torrent file has the suffix
.torrent. Torrent files have an "announce" section, which specifies the URL of the tracker, and an "info" section, containing (suggested) names for the files, their lengths, the piece length used, and a SHA-1 hash code for each piece, all of which are used by clients to verify the integrity of the data they receive.Torrent files are typically published on websites or elsewhere, and registered with at least one tracker. The tracker maintains lists of the clients currently participating in the torrent.[11] Alternatively, in a trackerless system (decentralized tracking) every peer acts as a tracker. Azureus was the first[citation needed] BitTorrent client to implement such a system through the distributed hash table (DHT) method. An alternative and incompatible DHT system, known as Mainline DHT, was later developed and adopted by the BitTorrent (Mainline), µTorrent, Transmission, rTorrent, KTorrent, BitComet, and Deluge clients.
After the DHT was adopted, a "private" flag — analogous to the broadcast flag — was unofficially introduced, telling clients to restrict the use of decentralized tracking regardless of the user's desires.[12] The flag is intentionally placed in the info section of the torrent so that it cannot be disabled or removed without changing the identity of the torrent. The purpose of the flag is to prevent torrents from being shared with clients that do not have access to the tracker. The flag was requested for inclusion in the official specification in August, 2008, but has not been accepted yet.[13] Clients that have ignored the private flag were banned by many trackers, discouraging
Downloading torrents and sharing files
Users find a torrent of interest, by browsing the web or by other means, download it, and open it with a BitTorrent client. The client connects to the tracker(s) specified in the torrent file, from which it receives a list of peers currently transferring pieces of the file(s) specified in the torrent. The client connects to those peers to obtain the various pieces. If the swarm contains only the initial seeder, the client connects directly to it and begins to request pieces.Clients incorporate mechanisms to optimize their download and upload rates; for example they download pieces in a random order to increase the opportunity to exchange data, which is only possible if two peers have different pieces of the file.
The effectiveness of this data exchange depends largely on the policies that clients use to determine to whom to send data. Clients may prefer to send data to peers that send data back to them (a tit for tat scheme), which encourages fair trading. But strict policies often result in suboptimal situations, such as when newly joined peers are unable to receive any data because they don't have any pieces yet to trade themselves or when two peers with a good connection between them do not exchange data simply because neither of them takes the initiative. To counter these effects, the official BitTorrent client program uses a mechanism called "optimistic unchoking", whereby the client reserves a portion of its available bandwidth for sending pieces to random peers (not necessarily known good partners, so called preferred peers) in hopes of discovering even better partners and to ensure that newcomers get a chance to join the swarm.[15]
Although swarming scales well to tolerate flash crowds for popular content, it is less useful for unpopular content. Peers arriving after the initial rush might find the content unavailable and need to wait for the arrival of a seed in order to complete their downloads. The seed arrival, in turn, may take long to happen (this is termed the seeder promotion problem). Since maintaining seeds for unpopular content entails high bandwidth and administrative costs, this runs counter to the goals of publishers that value BitTorrent as a cheap alternative to a client-server approach. This occurs on a huge scale; measurements have shown that 38% of all new torrents become unavailable within the first month.[16] A strategy adopted by many publishers which significantly increases availability of unpopular content consists of bundling multiple files in a single swarm.[17] More sophisticated solutions have also been proposed; generally, these use cross-torrent mechanisms through which multiple torrents can cooperate to better share content.[18]
BitTorrent does not offer its users anonymity. It is possible to obtain the IP addresses of all current and possibly previous participants in a swarm from the tracker. This may expose users with insecure systems to attacks.[15] It may also expose users to the risk of being sued, if they are distributing files without permission from the copyright holder(s). However, there are ways to promote anonymity; for example, the OneSwarm project layers privacy-preserving sharing mechanisms on top of the original BitTorrent protocol.
However there is a new way to convert a torrent file to an ordinary direct link
This conversion operation is because of the slowness of the torrent downloading
Some sites do this conversion
and this video show us how to do it
and these are some sites, that convert Torrent files to direct links
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