Getting computers to do some work

John von Neumann realized that a computer's instructions and its data can both be stored in the same memory. This is the idea of the stored-program computer.

RAM (random access memory) is the place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor. RAM is much faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM. However, the data in RAM stays there only as long as your computer is running. When you turn the computer off, RAM loses its data. When you turn your computer on again, your operating system and other files are once again loaded into RAM, usually from your hard disk.

An operating system acts like a traffic cop and manages application programs (i.e., MS Word is an application program). Users can interact directly with the operating system through a user interface such as a command language or a graphical user interface (GUI).

UNIX is an operating system that originated at Bell Labs in 1969 as an interactive time-sharing system.

Linus Torvalds was born in Helsinki, Finland in 1969. In 1991 he started work on Minix, a small Unix-like operating system. Torvalds developed his own version called Linux, a contraction for Linus' Minix. He did not copyright his computer code, but asked the members of the comp.os.minix newsgroup to help him build his operating system. The open-source philosophy behind the development of Linux means that only 2% of Linux code today was written by Torvalds himself.

May 15, 2003 How Microsoft Warded Off Rival By THOMAS FULLER International Herald Tribune BRUSSELS, May 14 — At least 90 percent of the world's personal computers run on Windows software. But Microsoft wanted still more. Last summer, Orlando Ayala, then in charge of worldwide sales at Microsoft, sent an e-mail message titled Microsoft Confidential to senior managers laying out a company strategy to dissuade governments across the globe from choosing cheaper alternatives to the ubiquitous Windows computer software systems. Mr. Ayala's message told executives that if a deal involving governments or large institutions looked doomed, they were authorized to draw from a special fund to offer the software at a steep discount or even free if necessary. Steven A. Ballmer, Microsoft's chief executive, was sent a copy of the e-mail message. The memo on protecting sales of Windows and other desktop software mentioned Linux, a still small but emerging software competitor that is not owned by any specific company. "Under NO circumstances lose against Linux," Mr. Ayala wrote.