豆知识 2011-05-15&05-21 比特风暴

 Our computer files aren’t like they used to be. These days a short HD video can be over a gigabyte in size. That's huge. The problem is that the bigger they are, the harder they are to share. Thankfully, we have options that make sharing big files over the Internet fast and easy. This is BitTorrent explained by Common Craft². 

Blake was so excited. He’s the present of his local Sasquatch fan club, and recently heard that a new video was circulating³. He couldn't rest until he had that video on his computer. He tried to download it from the original website, but it was painfully slow. Because so many fans were trying to download it at the same time, the website crashed. He was discouraged. 

Then a fellow fan said the video could also be downloaded via BitTorrent. She said that unlike typical downloads, file using BitTorrent actually download faster when more people are involved, and it works⁴ with any kind of file. 

To see for himself, Blake downloaded BitTorrent for free from BitTorrent.com. He opened the program and was a little confused. There were no videos and he wasn't sure where to start. But soon he realized that’s because BitTorrent is a little like a web browser⁵. Just like a browser needs websites to be useful, BitTorrent needs special files called torrents⁶ to work. A quick web search pointed⁷ him to websites with torrents galore.  Soon enough, he found the Sasquatch video torrent¹, downloaded the torrent file to his computer, and with a simple click, BitTorrent immediately sprang to action and the file started downloading. 

He could see it was working and wondered how. Later his friend made it clear by talking about how downloads typically work without BitTorrent. When someone downloads a file, it comes to their computer in a stream from a single source. When multiple⁸ people want the file, that single source can get overworked and can even shout down. BitTorrent solves this problem by making each downloader a source. This way, they get pieces of the file, but also provide pieces to each other. Together the downloaders become a network of multiple sources all working to provide pieces to one another. This makes downloads fast and realizable. 

A couple of things behind the scenes make it happen. First, when he clicked “Download”, Blake received the torrent file. This file has all the information about the video file, like what pieces are needed to complete it, but something is missing⁹. Blake needs a way to connect to other users¹⁰ who have the pieces he needs for his file. BitTorrent uses a computer called a tracker that helps Blake's computer find other computers called peers¹¹. The tracker keeps track of computers that are downloading or already have the whole file and introduces Blake's computer to them. With the connections in place, he receives what he needs, and also distributes pieces to others who are also downloading. 

Blake got it. BitTorren works because it turns downloaders into sources. And more downloaders means more sources and faster downloads.  

In the end, Brike's video downloaded in no time at all. But he was a little disappointed. What he thought was a Sasquatch was only a wookie. But at least he now knows that BitTorrent is a faster, easier way to download files from the Internet.

1 torrent   

n.激流，洪流；爆发，(话语等的)连发

参考例句：

• The torrent scoured a channel down the hillside. 急流沿着山坡冲出了一条沟。
• Her pent-up anger was released in a torrent of words.她压抑的愤怒以滔滔不绝的话爆发了出来。

2 craft   

n.工艺，手艺；小船，飞机；行业；诡计

参考例句：

• The harbour was full of pleasure craft.港口满是游艇。
• He's a master of his craft.他有一手好手艺。

3 circulating   

adj.& n.循环（的），流通（的）v.（使）循环( circulate的现在分词 )；（使）流通；（使）流传；散布

参考例句：

• The condition prevents the blood from circulating freely. 这种病阻碍了血液的循环畅通。
• The rumours were still circulating at Westminster. 当时谣言依然在英国议会和政府流传。

4 works   

n.作品，著作；工厂，活动部件，机件

参考例句：

• We expect writers to produce more and better works.我们期望作家们写出更多更好的作品。
• The novel is regarded as one of the classic works.这篇小说被公认为是最优秀的作品之一。

5 browser   

n.浏览者

参考例句：

• View edits in a web browser.在浏览器中看编辑的效果。
• I think my browser has a list of shareware links.我想在浏览器中会有一系列的共享软件链接。

6 torrents   

n.倾注；奔流( torrent的名词复数 )；急流；爆发；连续不断

参考例句：

• The torrents scoured out a channel down the hill side. 急流沿着山腰冲刷出一条水沟。 来自《现代汉英综合大词典》
• Sudden rainstorms would bring the mountain torrents rushing down. 突然的暴雨会使山洪暴发。 来自《现代汉英综合大词典》

7 pointed   

adj.尖的，直截了当的

参考例句：

• He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
• She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。

8 multiple   

adj.多个(或多项、多种)的；n.（数）倍数

参考例句：

• The number 8 is a multiple of 4.八是四的倍数。
• The most common multiple births are twins,two babies born at the same time.最常见的多胎是双胞胎，两个婴儿同时出生。

9 missing   

adj.遗失的，缺少的，失踪的

参考例句：

• Check the tools and see if anything is missing.检点一下工具，看有无丢失。
• All the others are here;he's the only one missing.别人都来了，就短他一个。

10 users   

用户，使用者( user的名词复数 )

参考例句：

• The new software will prove a boon to Internet users. 这种新软件将会对互联网用户大有益处。
• Ramps should be provided for wheelchair users. 应该给轮椅使用者提供坡道。

11 peers   

n.同等的人，贵族vi.凝视，窥视vt.与…同等，封为贵族v.凝视( peer的第三人称单数 )；盯着看；同等；比得上

参考例句：

• She enjoys the respect of her peers. 她受到同侪的尊敬。
• She peers into my eyes. 她盯着我的眼睛。 来自《简明英汉词典》