“Free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech,” not as in “free beer.” Free software is a matter of the users' freedom to run, copy, distribute, study, change and improve the software. More precisely, it means that the program's users have the four essential freedoms:
- The freedom to run the program, for any purpose (freedom 0).
- The freedom to study how the program works, and change it to make it do what you wish (freedom 1). Access to the source code is a precondition for this.
- The freedom to redistribute copies so you can help your neighbor (freedom 2).
- The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.
The Free Software Foundation (FSF) is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software.
GNU (//) is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system" composed wholly of free software. Development of GNU was initiated by Richard Stallman in 1983 and was the original focus of the Free Software Foundation (FSF), but no stable release of GNU yet exists as of September 2010.
REVOLUTION OS中记录了Linux的创建人Linus Torvalds以及Richard Stallman, Bruce Perens, Eric Raymond, Brian Behlendorf, Michael Tiemann, Larry Augustin, Frank Hecker, Rob Malda等人的生活经历或者采访记录。