什麼是網際網路

公眾存取的電腦網路，由來自世界各地許多較小的網路連線而成。產生於美國國防部計畫，稱為ARPANET（高等研究計畫署網路），建造於1969年，連線加州大學洛杉磯分校、史丹福研究所、加州大學聖塔巴巴拉和猶他大學的電腦。ARPANET目的在於研究電腦網路在戰爭的情況下提供安全無虞的通訊系統。當網路快速擴張，大學院校與其他領域研究人員也加以利用。1971年發展出第一個在分散網路傳送電子郵件的程式，1973年建立ARPANET的國際線路（從英國及挪威），電子郵件佔去ARPANET大多數的流量。1970年代還見到郵件名單、新聞群組及電子布告欄及TCP/IP通訊協定的發展，後者在1982～1983成為ARPANET的標準協定，導致網際網路的廣泛使用。1984年引進網域名稱定址系統。1986年美國國家科學基金會建立NSFNET，足以處理更大流量的分散式網路，不到一年就有超過1萬主機連上網際網路。1988年由於網際網路中繼聊天協定（參閱chat）的發展，在網路上即時交談成為可能。1990年ARPANET結束，留下NSFNET，第一家商業撥接存取網際網路的公司出現。1991年全球資訊網公諸在世人面前（藉由FTP）。Mosaic瀏覽器在1993年發行，隨著它的普及導致全球資訊網的網站與使用者激增。1995年NSFNET迴歸研究網路的角色，將網際網路的流量留給網路提供者傳遞，而不用國家科學基金會的超級電腦。這一年全球資訊網變成網際網路最受歡迎的部分，流量超越FTP協定。1997年時網際網路上有1000萬個以上的主機，註冊的網域名稱超過100萬。網際網路存取現在可以藉由無線電波訊號、有線電視、衛星、光纖線路，雖然大多數的流量還是利用公眾電信（電話）網路。一般認為網際網路對於人類文化與商業的各個層面都有重大的影響，但其機制仍有待釐清。

Internet

Publicly accessible computer network connecting many smaller networks from around the world. It grew out of a U.S. Defense Department program called ARPANET (Advanced Research Projects Agency Network), established in 1969 with connections between computers at UCLA, Stanford Research Institute, UC-Santa Barbara, and the University of Utah. ARPANET's purpose was to conduct research into computer networking in order to provide a secure and survivable communications system in case of war. As the network quickly expanded, academics and researchers in other fields began to use it as well. In 1971 the first program for sending E-mail over a distributed network was developed; by 1973, the year international connections to ARPANET were made (from Britain and Norway), E-mail represented most of the traffic on ARPANET. The 1970s also saw the development of mailing lists, newsgroups and bulletin-board systems, and the TCP/IP communications protocols, which were adopted as standard protocols for ARPANET in 1982-83, leading to the widespread use of the term Internet. In 1984 the domain name addressing system was introduced. In 1986 the National Science Foundation established the NSFNET, a distributed network of networks capable of handling far greater traffic, and within a year more than 10,000 hosts were connected to the Internet. In 1988 real-time conversation over the network became possible with the development of Internet Relay Chat protocols (see chat). In 1990 ARPANET ceased to exist, leaving behind the NSFNET, and the first commercial dial-up access to the Internet became available. In 1991 the World Wide Web was released to the public (via FTP). The Mosaic browser was released in 1993, and its popularity led to the proliferation of World Wide Web sites and users. In 1995 the NSFNET reverted to the role of a research network, leaving Internet traffic to be routed through network providers rather than NSF supercomputers. That year the Web became the most popular part of the Internet, surpassing the FTP protocols in traffic volume. By 1997 there were over 10 million hosts on the Internet and over 1 million registered domain names. Internet access can now be gained via radio signals, cable-television lines, satellites, and fiber-optic connections, though most traffic still uses a part of the public telecommunications (telephone) network. The Internet is widely regarded as a development of vast significance that will affect nearly every aspect of human culture and commerce in ways still only dimly discernible.