Running Linux, 5th Edition - Matthias Kalle Dalheimer [22]
Can't find the application you're looking for? A number of web sites provide comprehensive directories of Linux applications. The best known is Freshmeat (http://www.freshmeat.net); a couple others are listed in Appendix A. Take a look at these sites just to see the enormous amount of code that has been developed for Linux.
If you absolutely can't find what you need, you can always attempt to port the application from another platform to Linux. Or, if all else fails, you can write the application yourself. That's the spirit of free software—if you want something to be done right, do it yourself! While it's sometimes daunting to start a major software project on your own, many people find that if they can release an early version of the software to the public, many helpers pop up in the free software community to carry on the project.
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[*] On a 32-bit architecture; on a 64-bit architecture, up to 64 CPUs are supported, and patches are available that support up to 256 CPUs.
[*] If you are a real OS geek, you will note that swap space is inappropriately named: entire processes are not swapped, but rather individual pages of memory are paged out. Although in some cases entire processes will be swapped out, this is not generally the case. The term "swap space" originates from the early days of Linux and should technically be called "paging space."
[*] X.org actually derives from another PC-based version of the X Window System, XFree86. Political quarrels that we do not want to go into here have led to a split into XFree86 and X.org; most Linux distributions these days ship the X.org version. This is not relevant for you, though, unless you plan to help with the continued development of the X Window System.
About Linux's Copyright
Linux is covered by what is known as the GNU GPL. The GPL, which is sometimes referred to as a "copyleft" license, was developed for the GNU project by the Free Software Foundation. It makes a number of provisions for the distribution and modification of "free software." "Free," in this sense, refers to freedom, not just cost. The GPL has always been subject to misinterpretation, and we hope that this summary will help you to understand the extent and goals of the GPL and its effect on Linux. A complete copy of the GPL is available at http://www.gnu.org/copyleft/gpl.html.
Originally, Linus Torvalds released Linux under a license more restrictive than the GPL, which allowed the software to be freely distributed and modified, but prevented any money changing hands for its distribution and use. The GPL allows people to sell and make profit from free software, but doesn't allow them to restrict the right for others to distribute the software in any way.
A Summary of Free Software Licensing
First, we should explain that "free software" covered by the GPL is not in the public domain. Public domain software is software that is not copyrighted and is literally owned by the public. Software covered by the GPL, on the other hand, is copyrighted to the author or authors. This means that the software is protected by standard international copyright laws and that the author of the software is legally defined. Just because the software may be freely distributed doesn't mean it is in the public domain.
GPL-licensed software is also not "shareware ." Generally, shareware software is owned and copyrighted by the author, but the author requires users to send in money for its use after distribution. On the other hand, software covered by the GPL may be distributed and used free of charge.
The GPL also allows people to take and modify free software, and distribute their own versions of the software. However, any derived works from GPL software must also be covered by the GPL. In other