The Internet is the world’s largest group of cooperating computer networks. All the computers on the more than 100,000 networks that comprise the lnternet voluntarily use the same technical standards for their network date so that any of the computers on any of the networks can exchange messages with any other. Each message sent is broken up into small chunks of roughly uniform (相同的) size, called packets; each packet is sent along to its destination. If a packer’s destination is on a different network from its origin, the packet is switched from network to network until it reaches its destination. The destination computer reassembles incoming packets into the desired message. The "packet switched" design has let the Internet grow from its original two networks to its current size and beyond without any fundamental changes in the way that it works.
The Internet’s origins date from the late 1960s. During the 1980s, many new networks connected to the growing Interact-including both academic networks and the commercial networks. In 1996, Microsoft’s Explorer challenged Netscape’s dominance as Microsoft aggressively released new versions at no charge. Most Interact growth since 1994 has been centered around the Web, which has adopted or made obsolete (废弃的) most of the older serves other than e-mail. The Web easier is far to use than previous Net services, since it combines graphics with text and requires little typing; most actions are clicks of the mouse.
Microsoft Explorer challenged Netscape’s dominance by______.