Operating Systems
There is one special program called the operating system (OS) which manages the computer's operations, controlling devices and overseeing other programs, called applications. It stores and manages data and controls the sequence of the software and hardware actions. When the user requests that a program run, the operating system loads the program into the computer's memory and runs it. Popular OSs include Windows by Microsoft, UNIX, and the Macintosh OS.

Networks
Computers can communicate with other computers through a network to exchange data and share software and hardware resources.
Local area network (LAN)
consists of several PCs or workstations connected to a special computer called the server. The server stores and manages programs and data. Mainframe computers and supercomputers are usually connected to PCs, workstations, or "dumb" terminals used only to enter data into, or receive output from, the central computer.
Wide area networks (WANs)
Computers can connect to these networks to use facilities in another city or country. The largest WAN is the Internet.
Computers are more often also being equipped with a modem for connecting to the Internet and 'surfing' the WWW. The WWW is a system of information accessed through the Internet.

Alan Turing was a British mathematician who conceived of a machine that could compute by reading and writing an infinite tape according to some simple instructions and state transitions. From this he was able to show the existence of uncomputable functions. He played a significant rôle in cracking German codes during World War 2, and proposed a test for machine intelligence.

Database
A database is an information set organized for flexible searching and utilization. There are a wide array of databases, from simple examples such as simple tabular collections to much more complex models such as the relational model. The types of database are distinguished by many characteristics. One commonly used characteristic is the programming model associated with the database. Several models have been in wide use for some time.

Graphics
The first computer graphics were the output of text and numbers on electronic displays, though computer graphics today typically refers to creating images and not text. This field can be divided into two general areas: real-time rendering, and non real-time rendering. Development in computer graphics was first fueled by academic interests and government sponsorship. However, as real-world applications of computer graphics(CG) in broadcast television and movies proved a viable alternative to more traditional special effects and animation techniques, commercial parties have increasingly funded advances in the field.

Home Computers
This article discusses the early commercial computers that tended to be used in the home rather than for commercial purposes - during the 1980s. This breed of computer largely died out at the end of the decade due to the rise of the IBM PC compatible personal computer.

Internet
The Internet is a vast international public communications network that interconnects thousands of small and large networks so that they work as a single network to permit communication between any two connected end points. A world-wide collection of computer networks, connecting government, military, educational and commercial institutions, as well as private citizens to a wide range of computer services, resources, data and information. The WWW is built on the Internet.

Microsoft
Microsoft Corporation is the largest private-sector computer software producer in the world, headquartered in Redmond, Washington (a suburb of Seattle). The company was founded in 1975 by Bill Gates and Paul Allen to develop and sell BASIC interpreters.

Personal
A personal computer (PC) is an inexpensive microcomputer originally designed to be used by only one person at a time. The earliest known use of the term was in New Scientist magazine in 1964, in a series of articles called "The World in 1984". In "The Banishment of Paper Work," Arthur L. Samuel of IBM's Watson Research Center writes, "While it will be entirely feasible to obtain an education at home, via one's own personal computer, human nature will not have changed."

Programming and Software
Software is the various kinds of programs used to operate computers and related devices. A program is a sequence of instructions that tells a computer what operations to perform. Programs can be built into the hardware itself, or they may exist independently in a form known as software. Hardware describes the physical components of computers and related devices.

Computer Science
Computer science is the study of computers and their applications, in all aspects, as well as the mathematical structures that relate to computers and computation. Only in the last third of the 20th century has computer science been recognized as a separate discipline and developed its own methods and terminology. It has roots in electrical engineering, mathematics and linguistics, and is a blend of science, engineering and art. Computer science emphasizes the eternal truths of software and computers while Software engineering emphasize practical applications of software. In some ways they are the flip sides of the same coin. In other ways they are totally different.

Alan Turing
Alan Mathison Turing, b. June 23, 1912, d. June 7, 1954, was a British mathematician who conceived of a machine that could compute by reading and writing an infinite tape according to some simple instructions and state transitions. From this he was able to show the existence of uncomputable functions. For example, no program can determine if any arbitrary program will terminate. He played a significant rôle in cracking German codes during World War 2, and proposed a test for machine intelligence.