GNU Linux

The real Linux includes only the kernel, realized originally in 1991 by Linus Torvalds, after working on Minix, one of the several Unix versions. The complete source code of Minux core could be studied and understood, but it was forbidden to modify and spread it.

Through the years a big community of developers (formed by thousands of students, researchers and hackers) has grown around Torvalds.

The kernel is the central core controlling the functioning of the whole computer. Its role consists in letting all the machine physical resources available through a well-defined interface (the system calls), allowing the applications to use the calculation machine below.

Most of the outline applications are realized by GNU (GNU's Not UNIX, pronounced “guh-noo”). The GNU project has been started in 1983 by Richard Stallman in order to realize a complete operative and, above all, free system.

Both Linux kernel and GNU software are released under GPL (General Public Licence) and LGPL (Library GPL) licences. These licences assure the copyright safeguarding from the author and even the possibility to modify the source code from the the software user.

In this way GNU/Linux is a free software allowing the user to:

• run a programme for any purpose;

• modify the programme according to one's own requirements, through free access to source code;

• spread copies of the programme, for free or paying;

• spread modified copies of the programme, so that the community can take advantage on the improvements.