Picture a computer so big it weighed 250 tons and consumed more than a million watts of power. Its 55,000 vacuum tubes and countless flashing lights generated fantastic amounts of heat, and the beast had to be kept cool at all times. Otherwise, its magnetic core memories would melt away in just sixty seconds. IBM built nearly sixty of these massive machines for America's first computerized air defense system, starting in the mid-1950s. The system was called SAGE — Semi-Automatic Ground Environment. Each of the computers required more than a hundred people to operate and maintain it, and the systems were kept in service for nearly thirty years. The power-hungry behemoths had just 64 kilobytes of memory space, and could perform about 75,000 instructions per second — tiny fractions of the capabilities now offered in a single, one-pound computer that nestles in the palm of your hand.

During the lifespan of SAGE, thousands of computer programmers and technicians had to be trained, and many migrated to commercial computer companies once they left the military. They became the backbone of hardware and software innovations in the United States in the 1980s and 1990s and helped make possible the creation of the Internet, which eventually gave rise to the World Wide Web and virtually everything now available online.

SAGE, however, was not the only computer game in town. Between World War II and the early 1990s, a number of brilliant thinkers independently created concepts that advanced computer science and stirred many other inventive minds. For example, in a 1945 Atlantic Monthly article, a leading U.S. weapons scientist, Vannevar Bush, unveiled his concept for a mechanical desk that could serve as a library and private information file. Bush envisioned a personal unit with a viewing screen and the ability to store information that could be consulted “with exceeding speed and flexibility.” Two decades later, the author Marshall McLuhan popularized the concept of an interconnected “global village” able to communicate over “an electronic nervous system.” In the mid-1960s, computer researcher Douglas Engelbart developed the first computer mouse, followed soon by the first graphical user interface and the first working hypertext system.

Positive Fallout

The U.S. Defense Department and the Cold War both get some credit for the rise of the Internet. In the 1960s, while the Vietnam War was raging, the Cuban Missile Crisis was still fresh on many U.S. leaders' minds. Devices known as “computers” were beginning to play bigger roles in national government and military planning. Nobody yet had these cantankerous machines in their homes. The early devices filled up entire rooms and buildings, gulped electricity by the megawatt, and needed small armies of technicians and operators to keep them going. Planners soon realized that many computers would be needed to meet the growing needs of the government and the armed forces. But if the computers were put in one huge computing facility, it would be a very tempting target for the Soviet Union's long-range bombers and missiles.

A new concept soon emerged. If computers could be distributed to key scientific research and industrial facilities across the nation and linked with the Pentagon's computers through leased lines, at least some of the government's and military's command-and-control structure would survive a nuclear attack. The idea soon led to a grant from the Advanced Research Projects Agency (ARPA), and ARPANET was born.

A computer at the University of California at Los Angeles (UCLA) was the first one added to the fledgling network in 1969, followed soon afterward by other computers in California and Utah. During the 1970s, ARPANET continued to expand, adding connections to many other universities that were trying to develop better data networks and methods of data processing.

Communications on ARPANET were complicated by the fact that most of the linked computers used different and typically incompatible operating systems. Early in the 1980s, the Defense Department settled on Internet Protocol (IP) as its networking standard. Gradually, it broke away from ARPANET and created its own network, MILNET. As other agencies and facilities adopted the IP standard, ARPANET lost ground, and the Internet expanded and replaced it.

Home Advantage

Desktop personal computers hit the marketplace in the late 1970s and quickly began popping up in homes and businesses. PC buyers initially used their machines to create documents and help manage their finances. But, with help from external and internal modulator-demodulator (modem) boards and telephone lines, PC owners began using the first commercial email service, CompuServe, in 1979, to send messages to each other. They also started joining specialized “newsgroups,” where they could read and respond to messages posted by other group members who shared their interests. Articles and information began to be posted that users could read, print out, or download as research materials. Text advertisements sometimes appeared on the dial-up sites, and businesses started sending out e-mail messages to try to sell things. CompuServe also introduced the first online chat service in 1980. By the early 1990s, CompuServe was the home of numerous online moderated forums on a wide range of topics. Several companies also used forums to provide technical support to their customers.

For computer users, the focus remained on logging on to proprietary sites to find information or people who shared their interests — not merchandise.

Browser Power

At first, the World Wide Web continued to be a special playground for skilled computer users. That quickly changed in 1994, when Marc Andreessen and Netscape brought the first commercial Web browser to the public, followed soon by Microsoft and its Internet Explorer. As a result, computer users could quickly search the Internet for links to information, and they could visit Web sites run by individuals, companies, agencies, and schools almost anywhere on the planet. They weren't limited to the offerings of one source, such as CompuServe, America Online, or Prodigy.