GNU

GNU (pronounced /gnu/ (help·info)) is a free operating system consisting of a kernel, libraries, system utilities, compilers, and end-user applications. Its name is a recursive acronym for "GNU's Not Unix", which was chosen because its design is Unix-like, but differs from Unix by being free software and by not containing actual UNIX code. The plan for the GNU operating system was announced in September 1983 by Richard Stallman and software development work began in January 1984. As of 2006, GNU is still in active development. The project to develop GNU is known as the GNU Project, and programs released under the auspices of the GNU Project are called GNU packages or GNU programs.

Microsoft Office

Microsoft Office is a suite of productivity programs created or purchased by Microsoft and developed for Microsoft Windows, and Apple Computer's Mac OS and Mac OS X operating systems. As well as the office applications, it includes associated servers and Web-based services. Recent versions of Office are now called the "Office system" rather than the "Office suite" to reflect the fact that they include servers as well.

OpenOffice

OpenOffice.org is a free and open source office suite, including word processor, spreadsheet, presentation, vector drawing and database components. It is available for many different platforms, including Microsoft Windows, Unix-like systems with the X Window System including GNU/Linux, BSD, Solaris and Mac OS X. It is intended to be a compatible, free alternative to Microsoft Office. It supports the OpenDocument standard for data interchange.

Windows

Microsoft Windows is a family of operating systems by Microsoft for use on personal computers, although versions of Windows designed for servers, embedded devices, and other platforms also exist. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing trend of graphical user interfaces popularized first by Xerox, and then the Apple Macintosh. Microsoft Windows eventually came to dominate the world's personal computer market. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market

Linux

Linux (also known as GNU/Linux) is a Unix-like computer operating system. It is one of the most prominent examples of open source development and free software; unlike proprietary operating systems such as Windows or Mac OS, all of its underlying source code is available to the public for anyone to freely use, modify, and redistribute.