Name: xin lin

Course: CS 456

Professor: blundell

Due Date: February 14, 2002

The personal computer (PC) has revolutionized business and personal activities and even the way people talk and think; however, its development has been less of a revolution than an evolution and convergence of three critical elements - thought, hardware, and software. Although the PC traces its lineage to the mainframe and minicomputers of the 1950s and 1960s, the conventional thought that was prevalent during the first thirty years of the computer age saw no value in a small computer that could be used by individuals.

At the time abacus was invented in Babylonia, people wanted to find the easier and faster way to compute. At the Institute for Advanced Study in Princeton, Hungarian-American mathematician John von Neumann developed one of the first computers used to solve problems in mathematics, meteorology, economics, and hydrodynamics. He plays the very important role in the history of computer development. Von Neumann's 1945 Electronic Discrete Variable Computer (EDVAC) was the first electronic computer to use a program stored entirely within its memory.  Engineer John Mauchley, an American physicist, proposed an electronic digital computer, called the , which was built at the Moore School of Engineering at the University of Pennsylvania in Philadelphia by Mauchley and J. Presper Eckert, an American ENIAC was completed in 1945 and is regarded as the first successful, general digital computer. It weighed more than 27,000 kg (60,000 lb), and contained more than 18,000 vacuum tubes. Roughly 2000 of the computer's vacuum tubes were replaced each month by a team of six technicians. Many of ENIAC's first tasks were for military purposes, such as calculating ballistic firing tables and designing atomic weapons. Since ENIAC was initially not a stored program machine, it had to be reprogrammed for each task. Eckert and Mauchley eventually formed their own company, which was then bought by the Rand Corporation. They produced the Universal Automatic Computer (UNIVAC), which was used for a broader variety of commercial applications.

Manufacturers used integrated circuit technology to build smaller and cheaper computers. The first of these so-called personal computers (PCs) was sold by Instrumentation Telemetry Systems. The Altair 8800 appeared in 1975. It used an 8-bit Intel 8080 microprocessor, had 256 bytes of RAM, received input through switches on the front panel, and displayed output on rows of light-emitting diodes (LEDs). Refinements in the PC continued with the inclusion of video displays, better storage devices, and CPUs with more computational abilities. Graphical user interfaces were first designed by the Xerox Corporation, then later used successfully by the Apple Computer Corporation with its Macintosh computer. Today the development of sophisticated operating systems such as Windows 95 and Unix enables computer users to run programs and manipulate data in ways that were unimaginable 50 years ago.

The Internet is a worldwide network of thousands of computers and computer networks. It is a public, voluntary, and cooperative effort between the connected institutions and is not owned or operated by any single organization.

The Internet and Transmission Control Protocols were initially developed in 1973 by American computer scientist Vinton Cerf as part of a project sponsored by the United States Department of Defense Advanced Research Projects Agency (ARPA) and directed by American engineer Robert Kahn. The Internet began as a computer network of ARPA (ARPAnet) that linked computer networks at several universities and research laboratories in the United States. The World Wide Web was developed in 1989 by English computer scientist Timothy Berners-Lee for the European Organization for Nuclear Research (CERN).

Internet, interconnection of computer networks that enables connected machines to communicate directly. The term popularly refers to a particular global interconnection of government, education, and business computer networks that is available to the public. There are also smaller internets, usually for the private use of a single organization, called intranets. Internet technology is a primitive precursor of the Information Superhighway, a theoretical goal of computer communications to provide schools, libraries, businesses, and homes universal access to quality information that will educate, inform, and entertain. In early 1996, the Internet interconnected more than 25 million computers in over 180 countries and continues to grow at a dramatic rate.

The GUI that made the computer an "intuitive" extension of the user, the "Mac" had its own operating system that was incompatible with IBM's MS-DOS system. Suddenly PC meant DOS-based and IBM compatible and Mac meant GUI and mouse. The Mac was introduced to the world in an extravagant television commercial that was shown only once during half-time of the NFL Super Bowl. The commercial changed the advertising industry almost as much as the Mac changed computing. The 1980s were very active times for hardware manufacturers and software producers. Small software companies locked in with either IBM or Macintosh, but large companies like Microsoft were able to create new applications for both operating systems. While Aldus brought out PageMaker, and Lotus introduced Jazz, Microsoft announced Excel for the Mac, C 3.0, and finally shipped a long-awaited program called Windows.

But PCs that were connected to the outside world were also vulnerable to a new phenomenon called viruses. Once downloaded, these programs could attach themselves without warning to a PC's hard drive and gradually or in the blink of an eye destroy or overwrite files. Virus checkers then became the rage for anyone who received data over telephone lines.

Today the PC is a communication channel more than it is a computational tool. Millions of people work in their "electronic cottages," either operating their own business from home or telecommuting to work. It is strange that one of the first Intel 4004 microprocessors ever made, continues to operate and lead the world to the outer edges of time and space. In 1972 one of the small chips was installed in the Pioneer spacecraft. Today it continues to operate over 5 billion miles from earth.