Google Inc.'s move to offer its own Web browser begs a question about a technology that most people now take for granted: What exactly is a Web browser?

The short answer is that it is a piece of software that takes us where we want to go, whether to buy a pair of pants or call up a bus schedule. To understand what a browser really does, though, it helps to understand why it was invented.

Computers were once isolated calculation engines. A user walked up to them, inserted a stack of punch cards or pushed some buttons, and waited for an answer. Later users could interact with a specific system using terminals sold by each computer maker, a phase followed by networks that could connect different kinds of computers run by individual organizations.

In the 1970s, researchers agreed on a set of specifications to send packets between those dissimilar systems -- akin to the address scheme the post office uses to route letters. Thus was born the Internet.

But viewing information on someone else's computer still wasn't easy. For one thing, the information might be stored in a database or other proprietary software that varied among organizations. Tim Berners-Lee, the man credited with inventing the Web, wanted to break down those barriers.

He built on a technology known as hypertext -- the notion of establishing links to connect any concept, or document, to any other. That required developing and popularizing three sets of rules for creating and exchanging documents.

One is hypertext transfer protocol, or HTTP, which establishes specifications for linking documents. Another is an address scheme for findingdocuments, known as a universal resource locator, or URL. Third is a way to create documents in a consistent format, known as hypertext markup language, or HTML.

But there was still one key element missing: a piece of desktop software to display documents created using HTML, and respond to the communications instructions based on HTTP and URL. So Mr. Berners-Lee created the first browser, a type of program that would later be refined by Netscape Communications Corp., Microsoft Corp. and others.

Today's browsers have been updated to do additional tricks. By using small programs, known as plug-ins, they can allow users to view videos and animations.

But browsers still must manage the more basic chores of displaying documents and navigating between them. When a user clicks on a link on a Web page -- or types a URL into the address line and hits return -- the browser sends a request for information that is converted into data packets and sent out to the Internet.

The request is routed through organizations that manage directories of domain names, and store numerical addresses associated with those names. Once that request reaches the server with that address, it responds by sending a new Web page that bounces back around the Internet to pop up on the user's browser.

谷歌(Google Inc.)计划推出自主开发的网络浏览器；但这并不意味着人人都了解这项大家都习以为常的技术。那么，究竟什么是网络浏览器呢？

简单的说，网络浏览器就是一款软件，能带我们去想去的网站，无论是去买条裤子还是查询公交时刻表。不过，为了理解网络浏览器的真正用途，我们有必要回顾下浏览器的诞生历史。

最初，电脑是孤立的运算机器。使用者打开机器，插入一张穿孔卡片或按下某些按键，然后等待机器给出一个答案。后来，使用者可以使用电脑制造商出售的终端，通过一个特殊系统与机器进行互动；接下来出现了电脑网络，它能够将各单独组织运行的各种电脑连接起来。

在20世纪70年代，研究人员确定了一系列标准，得以在不同系统之间发送信息包──这类似于邮局发送信件的地址系统。互联网由此诞生了。

不过，浏览他人电脑上的信息仍非易事。首先，信息可能存储在数据库，或其他所有权软件中，而各组织所采用的又各不相同。Web之父蒂姆•伯纳斯•李(Tim Berners-Lee)当时希望能够打破这些障碍。

他利用一种称为超文本的技术，提出了在任何概念和文件之间建立连接的想法。由此发展并推广了三套技术标准，用于创建与交换文件。

其中之一就是超文本传输协议，即HTTP，为文件连接确定了标准。另一套标准是统一资源定位符，即URL，用于寻找文件的地址系统。第三套标准是超文本置标语言，即HTML，以一致的格式创建文件。

不过，我们还需要一个关键要素：一个可以显示以HTML标准创建的文件、并可以响应基于HTTP与URL标准通信指令的电脑软件。因此，伯纳斯•李发明了第一个浏览器；在这个基础上，Netscape Communications Corp.、微软(Microsoft Corp.)以及其他公司后来纷纷研发了各自的浏览器软件。

如今的浏览器已经过升级，可以进行更多的任务。通过使用俗称插件的小程序，用户可以通过浏览器观看视频和动画。

不过浏览器仍然必须满足最基本的显示文件和浏览功能。当用户点击网页上的链接时，或是在地址栏输入URL网址然后点击回车，浏览器就会发送一条相应的信息请求，这些信息已被转化为数据包并发送到了互联网上。

这一请求信息要途经管理域名地址录、并储存这些域名相关地址的组织。一旦信息请求抵达目的服务器，服务器就会发送一个新的网页，沿着互联网回复到用户的浏览器上。
关键字:计算机英语
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