天津的大伙伴 发表于 2020-3-26 21:06:59

BitTorrent协议(简称BT,俗称比特洪流、BT下载)

<h1 id="firstHeading" class="firstHeading" style="color: rgb(0, 0, 0); margin: 0px 0px 0.25em; padding: 0px; overflow: visible; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.8em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;" lang="zh-Hans-CN">BitTorrent (协议)<span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important;"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important;"></span></span></h1><div><br></div><div id="bodyContent" class="mw-body-content" style="position: relative; z-index: 0; font-size: 0.938em; line-height: 1.6; user-select: text !important; color: rgb(32, 33, 34); font-family: sans-serif; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"><div class="mw-parser-output" style="user-select: text !important;"><b style="user-select: text !important;">BitTorrent协议</b>(简称<b style="user-select: text !important;">BT</b>,俗称<b style="user-select: text !important;">比特洪流</b>、<b style="user-select: text !important;">BT下载</b>)是用在<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">对等网络</span>中<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">文件分享</span>的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">网络协议</span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">程序</span>。和<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">点对点</span>(point-to-point)的协议<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">程序</span>不同,它是用户群对用户群(peer-to-peer),而且用户越多,下载同一文件的人越多,下载该文件的速度越快。且下载后,继续维持上传的状态,就可以“分享”,成为其用户端节点下载的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">种子文件</span>(.torrent),同时上传及下载。<div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading" style="border: 1px solid rgb(162, 169, 177); background-color: rgb(248, 249, 250); padding: 7px; font-size: 14.2576px; display: table; user-select: text !important;"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="user-select: text !important; direction: ltr; position: absolute; opacity: 0; z-index: -1; display: none;"><div class="toctitle" dir="ltr" style="user-select: text !important; text-align: center; direction: ltr;" lang="zh-Hans-CN"><h2 id="mw-toc-heading" style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border: 0px; font-size: 14.2576px; font-weight: bold; user-select: text !important; font-family: sans-serif; line-height: 1.3; display: inline;">目录</h2><span class="toctogglespan" style="font-size: 13.4021px; user-select: text !important;"><label class="toctogglelabel" for="toctogglecheckbox" style="cursor: pointer; color: rgb(6, 69, 173); user-select: text !important;"></label></span></div><ul style="list-style-image: none; margin: 0.3em 0px; padding: 0px; user-select: text !important; list-style-type: none; text-align: left;"><li class="toclevel-1 tocsection-1" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">1</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">历史</span></span></li><li class="toclevel-1 tocsection-2" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">2</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">原理简述</span></span></li><li class="toclevel-1 tocsection-3" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">3</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">DHT网络</span></span></li><li class="toclevel-1 tocsection-4" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">4</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">BT中相关概念</span></span></li><li class="toclevel-1 tocsection-5" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">5</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">BitTorrent与自由软件</span></span></li><li class="toclevel-1 tocsection-6" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">6</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">历史</span></span></li><li class="toclevel-1 tocsection-7" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">7</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">影响</span></span></li><li class="toclevel-1 tocsection-8" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">8</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">支持此协议的软件</span></span></li><li class="toclevel-1 tocsection-9" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">9</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">相关条目</span></span></li><li class="toclevel-1 tocsection-10" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">10</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">参考文献</span></span></li><li class="toclevel-1 tocsection-11" style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;"><span class="tocnumber" style="display: table-cell; text-decoration: inherit; color: rgb(32, 33, 34); padding-left: 0px; padding-right: 0.5em; user-select: text !important;">11</span><span class="toctext" style="display: table-cell; text-decoration: inherit; user-select: text !important;">外部链接</span></span></li></ul></div><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id=".E6.AD.B7.E5.8F.B2" style="user-select: text !important;"></span><span class="mw-headline" id="歷史" style="user-select: text !important;">历史</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><p style="margin: 0.5em 0px; user-select: text !important;">该技术由美国的程序员<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">布莱姆·科亨</span>于2001年4月时发布,并于2001年7月2日时首次正式应用。</p><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id=".E5.8E.9F.E7.90.86.E7.B0.A1.E8.BF.B0" style="user-select: text !important;"></span><span class="mw-headline" id="原理簡述" style="user-select: text !important;">原理简述</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><div class="thumb tright" style="user-select: text !important; margin: 0.5em 0px 1.3em 1.4em; width: auto; background-color: transparent; clear: right; float: right;"><div class="thumbinner" style="user-select: text !important; border: 1px solid rgb(200, 204, 209); padding: 3px; background-color: rgb(248, 249, 250); font-size: 14.1075px; text-align: center; overflow: hidden; width: 359px;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="image"><img alt="" src="https://upload.wikimedia.org/wikipedia/commons/3/3d/Torrentcomp_small.gif" class="thumbimage" data-file-width="357" data-file-height="334" style="border: 1px solid rgb(200, 204, 209); vertical-align: middle; user-select: text !important; background-color: rgb(248, 249, 250);" width="357" height="334"></span><div class="thumbcaption" style="user-select: text !important; border: 0px; line-height: 1.4em; padding: 3px; font-size: 13.2611px; text-align: left;">BT原理在该图示中,由不同颜色区分的是某一文件的不同部分,当传输开始时,只有种子发布者拥有全部文件,在传输进行中,有部分用户获得部分文件(带颜色线条表示),随着传输的继续,文件已经全部公布在系统中,此时,种子拥有者可以退出,也不会影响该文件的传播</div></div></div><p style="margin: 0.5em 0px; user-select: text !important;">普通的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">HTTP</span>/<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">FTP</span>下载使用<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">TCP/IP协议</span>,BitTorrent协议是架构于TCP/IP协议之上的一个<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-disambig">P2P</span>文件传输<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">通信协议</span>,处于TCP/IP结构的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">应用层</span>。BitTorrent协议本身也包含了很多具体的内容协议和扩展协议,并在不断扩展中。</p><p style="margin: 0.5em 0px; user-select: text !important;">根据BitTorrent协议,文件发布者会根据要发布的文件生成提供一个.torrent文件,即<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">种子文件</span>,也简称为“种子”。</p><p style="margin: 0.5em 0px; user-select: text !important;">种子文件本质上是<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">文本文件</span>,包含Tracker信息和文件信息两部分。Tracker信息主要是BT下载中需要用到的Tracker服务器的地址和针对Tracker服务器的设置,文件信息是根据对目标文件的计算生成的,计算结果根据BitTorrent协议内的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">Bencode</span>规则进行编码。它的主要原理是需要把提供下载的文件虚拟分成大小相等的块,块大小必须为2k的整数次方(由于是虚拟分块,硬盘上并不产生各个块文件),并把每个块的索引信息和<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-disambig">Hash</span>验证码写入种子文件中;所以,种子文件就是被下载文件的“索引”。</p><p style="margin: 0.5em 0px; user-select: text !important;">下载者要下载文件内容,需要先得到相应的种子文件,然后使用BT客户端软件进行下载。</p><p style="margin: 0.5em 0px; user-select: text !important;">下载时,BT客户端首先解析种子文件得到Tracker地址,然后连接Tracker服务器。Tracker服务器回应下载者的请求,提供下载者其他下载者(包括发布者)的IP。下载者再连接其他下载者,根据种子文件,两者分别告知对方自己已经有的块,然后交换对方所没有的数据。此时不需要其他服务器参与,分散了单个线路上的数据流量,因此减轻了服务器负担。</p><p style="margin: 0.5em 0px; user-select: text !important;">下载者每得到一个块,需要算出下载块的Hash验证码与种子文件中的对比,如果一样则说明块正确,不一样则需要重新下载这个块。这种规定是为了解决下载内容准确性的问题。</p><p style="margin: 0.5em 0px; user-select: text !important;">一般的HTTP/FTP下载,发布文件仅在某个或某几个服务器,下载的人太多,服务器的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">带宽</span>很易不胜负荷,变得很慢。而BitTorrent协议下载的特点是,下载的人越多,提供的带宽也越多,下载速度就越快。同时,拥有完整文件的用户也会越来越多,使文件的“寿命”不断延长。</p><p style="margin: 0.5em 0px; user-select: text !important;">为了解决某些用户“下完就跑”的现象,在非官方BitTorrent协议中还存在一种慢慢开放下载内容的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">超级种子</span>的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">算法</span>。</p><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id="DHT.E7.BD.91.E7.BB.9C" style="user-select: text !important;"></span><span class="mw-headline" id="DHT网络" style="user-select: text !important;">DHT网络</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><p style="margin: 0.5em 0px; user-select: text !important;">目前,又发展出<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">DHT</span>网络技术,可以在无Tracker的情况下下载。</p><p style="margin: 0.5em 0px; user-select: text !important;">DHT全称为分布式哈希表(Distributed Hash Table),是一种分布式存储方法。在不需要服务器的情况下,每个客户端负责一个小范围的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">路由</span>,并负责存储一小部分数据,从而实现整个DHT网络的寻址和存储。使用支持该技术的BT下载软件,用户无需连上Tracker就可以下载,因为软件会在DHT网络中寻找下载同一文件的其他用户并与之通讯,开始下载任务。</p><p style="margin: 0.5em 0px; user-select: text !important;">有些软件(如<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">比特精灵</span>)还会自动通过DHT搜索种子资源,构成<span style="text-decoration: none; color: rgb(165, 88, 88); background: none; user-select: text !important;" class="new">种子市场</span>。</p><p style="margin: 0.5em 0px; user-select: text !important;">另外,这里使用的DHT算法叫<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">Kademlia</span>(在<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">eMule</span>中也有使用,称为<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">Kad网络</span>,具体实现协议有所不同)。</p><p style="margin: 0.5em 0px; user-select: text !important;">这种技术好处十分明显,就是大大减轻了Tracker的负担(甚至不需要)。用户之间可以更快速创建通讯(特别是与<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">Tracker</span>连接不上的时候)。</p><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id="BT.E4.B8.AD.E7.9B.B8.E5.85.B3.E6.A6.82.E5.BF.B5" style="user-select: text !important;"></span><span class="mw-headline" id="BT中相关概念" style="user-select: text !important;">BT中相关概念</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><ul style="list-style-image: url(&quot;/w/skins/Vector/resources/skins.vector.styles/images/bullet-icon.svg?d4515&quot;); margin: 0.3em 0px 0px 1.6em; padding: 0px; user-select: text !important;"><li style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">Tracker</span>:收集下载者信息的服务器,并将此信息提供给其他下载者,使下载者们相互连接起来,传输数据。</li><li style="margin-bottom: 0.1em; user-select: text !important;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">种子</span>:指一个下载任务中所有文件都被某下载者完整的下载,此时下载者成为一个种子。发布者本身发布的文件就是原始种子。</li><li style="margin-bottom: 0.1em; user-select: text !important;">做种:发布者提供下载任务的全部内容的行为;下载者下载完成后继续提供给他人下载的行为。</li></ul><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id="BitTorrent.E8.88.87.E8.87.AA.E7.94.B1.E8.BB.9F.E4.BB.B6" style="user-select: text !important;"></span><span class="mw-headline" id="BitTorrent與自由軟件" style="user-select: text !important;">BitTorrent与自由软件</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><p style="margin: 0.5em 0px; user-select: text !important;">BitTorrent对于大型文档和<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">自由软件</span>如<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">Linux</span>、<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">FreeBSD</span>的发布帮助很大。对于发布数百<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">MiB</span>以至数十<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">GiB</span>的文件时,如<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">Fedora</span>的<span style="text-decoration: none; color: rgb(165, 88, 88); background: none; user-select: text !important;" class="new">光盘镜像格式</span>档,BitTorrent的使用能大大减低<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">服务器</span>的<span style="text-decoration: none; color: rgb(165, 88, 88); background: none; user-select: text !important;" class="new">数据流量</span>从而减低发布的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">成本</span>。另外,一般有新版本软件推出时,链接该服务器的人数必定非常庞大,使用BitTorrent也能大大减低繁忙时间服务器的负担。</p><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id=".E5.8E.86.E5.8F.B2" style="user-select: text !important;"></span><span class="mw-headline" id="历史" style="user-select: text !important;">历史</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><p style="margin: 0.5em 0px; user-select: text !important;">2002年,<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">布莱姆·科亨</span>在<span style="text-decoration: none; color: rgb(165, 88, 88); background: none; user-select: text !important;" class="new">CodeCon</span>初次露面,发表首个BT软件<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">BitTorrent</span>。它以<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">Python</span>写成,以<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">MIT许可证</span>发布。</p><h2 style="color: rgb(0, 0, 0); margin: 1em 0px 0.25em; padding: 0px; overflow: hidden; border-bottom: 1px solid rgb(162, 169, 177); font-size: 1.5em; font-weight: normal; user-select: text !important; font-family: &quot;Linux Libertine&quot;, Georgia, Times, serif; line-height: 1.3;"><span id=".E5.BD.B1.E5.93.8D" style="user-select: text !important;"></span><span class="mw-headline" id="影响" style="user-select: text !important;">影响</span><span class="mw-editsection" style="font-family: sans-serif; user-select: text !important; font-size: small; font-weight: normal; margin-left: 1em; vertical-align: baseline; line-height: 1em; unicode-bidi: isolate;"><span class="mw-editsection-bracket" style="user-select: text !important; margin-right: 0.25em; color: rgb(84, 89, 93);"></span><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span><span class="mw-editsection-bracket" style="user-select: text !important; margin-left: 0.25em; color: rgb(84, 89, 93);"></span></span></h2><p style="margin: 0.5em 0px; user-select: text !important;">以在线游戏为例,有些在线游戏的在线更新(如<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">魔兽世界</span>)就是采用BT的技术。所以当每次有改版时,动辄数百MiB的更新档,透过游戏厂商所提供的更新程序,以BT的方式进行下载分流。这为以往的其他种在线游戏,每次重大改版就必须重新压制光盘,或是等待单一下载点的下载方式,带来另一种节省成本的经营模式。</p><p style="margin: 0.5em 0px; user-select: text !important;">BT下载方式目前引起社会的广泛讨论。利用BT免费发布著作权内容肯定损害著作权所有者的合法权益,但传播非收费性内容的好处有目共睹。争论的焦点是,是否应因此立法全面禁止BT,并且对从事BT下载的人作出惩罚。目前为止,<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">中国大陆</span>和<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">西欧</span>等地区的国家,对BT仍没有任何法律上的约束。不过2009年12月,<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">国家广播电影电视总局</span>曾大范围打击和封锁在中国的Tracker服务器,以BTChina为代表的一批知名Tracker服务器均因此停止服务。</p><p style="margin: 0.5em 0px; user-select: text !important;">在<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">香港</span>,<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">陈乃明</span>因为发布<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">电影</span>的种子而被海关拘捕。2005年10月24日,香港司法机关裁定陈乃明的侵权罪成立,需要即时监禁三个月。香港工商贸易部门领导曾俊华与<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">海关</span>关长汤显明对今次裁决感到满意,并表示香港政府和业界将不容忍任何侵权行为的存在,同时政府亦会随时与商人合作打击侵权行为。香港海关再于2008年9月及2009年4月先后拘捕两人,分别为一名27岁任职收银员的女性及一名38岁无业的男性。他们都被怀疑以BT非法上传两套外国电影而被捕,其中男疑犯涉及的电影为英国电影《<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">故园风雨后</span>》(Brideshead Revisited)及美国电视电影《<span style="text-decoration: none; color: rgb(165, 88, 88); background: none; user-select: text !important;" class="new">十级飓风</span>》(NYC: Tornado Terror)。他们成为当局自2007年中激活,24小时运作的“网线监察系统”(Lineament Monitoring System)以来首两名被捕者,使香港因以BT非法上传而被捕人士的总数提升至三名<sup id="cite_ref-hongkong28042009_1-0" class="reference" style="line-height: 1; user-select: text !important; unicode-bidi: isolate; white-space: nowrap; font-weight: normal; font-style: normal;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span></sup><sup id="cite_ref-2" class="reference" style="line-height: 1; user-select: text !important; unicode-bidi: isolate; white-space: nowrap; font-weight: normal; font-style: normal;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span></sup><sup id="cite_ref-3" class="reference" style="line-height: 1; user-select: text !important; unicode-bidi: isolate; white-space: nowrap; font-weight: normal; font-style: normal;"><span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important; white-space: nowrap;"></span></sup>。</p><p style="margin: 0.5em 0px; user-select: text !important;">而在<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">台湾</span>,由于需受到美国<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">特别301报告</span>报复的压力,因此经常与<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">IFPI</span>及<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">商业软件联盟</span>(<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-disambig">BSA</span>)等商业著作权组织合作查缉提供BT来源的网站及论坛,台湾论坛首度因为供应BT下载遭到被捕,卡提诺王国为全台湾最大的BT及违法分享的分享平台,也于不久后被法务部调查。</p><p style="margin: 0.5em 0px; user-select: text !important;">由于占大部分的BT下载都是歌曲或视频,尤以后者为多。举个例子,一集电视剧的大小约200至300<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">MiB</span>,而电影则是几百<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">MiB</span>至几<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">GiB</span>(1GiB=1024MiB),在以前没有BT技术前,要下载这些类视频是颇困难和花时间的。因此BT的发展使互联网用户下载视频的数量大大增加。除了下载本地的歌曲视频外,用户同时也能下载其他国家地区的歌曲视频,一些在其他国家播放的电视剧或综艺节目,次日BT网站已能提供下载。所以BT的发展也促使互联网用户更加快地能接触到其他国家的影视,而不需等待自己国家购买回来播放或出版<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">VCD</span>/<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">DVD</span>才能看。这样使用户多了选择,不需只跟随本地电视台或电影院播映什么,就只看什么。同样地,他们的<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-disambig">偶像</span>也渐渐由本地化转为国际化,以<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">大中华区</span>为例,年轻人追棒的偶像越来越多是来自其他国家,如<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;">日本</span>、<span style="text-decoration: none; color: rgb(11, 0, 128); background: none; user-select: text !important;" class="mw-redirect">韩国</span>等。而这或多或少和他们能透过BT下载其电视电影,更快和更多地接触外地信息娱乐有关。</p></div></div>
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