Unix-type operating system: Linux
Linux (or GNU / Linux) is a free Unix-type operating system (or Unix-like), incorporating elements of the Linux kernel with the GNU system and other software developed and distributed under GNU GPL or other free licenses. Linux is in fact the name of the kernel developed by Linus Torvalds in 1991 that integrated with components already created by the GNU (gcc, glibc and other utilities) and other software projects has been used as basis for the implementation of open source operating systems and distributions that are usually identified with the same name.
According to Richard Stallman, founder of the GNU project, and according to the Free Software Foundation, the term Linux (without the prefix “GNU /”) for the entire operating system is wrong, because the name is attributable to the Linux kernel and system only, structured components from the original GNU project, should more properly be called GNU / Linux. According to others, and second the use of most users and developers and companies involved in developing the operating system and software related to it, the name Linux has now become synonymous with “Linux based” system that is based on Linux kernel.
Using well-known servers, Linux is supported by companies like IBM, Sun Microsystems, Hewlett-Packard, Red Hat and Novell and is used as the operating system on a variety of hardware, from desktops to supercomputers, to embedded systems such as mobile phones and PDAs, and netbooks.
It is also an indispensable component of the LAMP server software, which has achieved wide popularity among web developers and that is present in most servers worldwide.
With the evolution of desktop environments like KDE and GNOME, the system offers a graphical interface similar to Microsoft Windows or Mac OS X closer to the needs of novice users, making the transition from one system to another less traumatic .
Linux initially was a simple terminal emulator written in C and assembly, and did not need to rely on an operating system. The terminal emulator up and run two threads: one to send signals to the serial port, one to receive them, then when Ben needed to read and write files to disk, this emulator was extended so that it could handle a file system.
Slowly, this program became a full kernel can handle an operating system and Linux started to read up on the POSIX specification, asking for assistance on the newsgroup message of August 25, 1991. The first version of the Linux kernel, 0.01, was published on the Internet September 17, 1991 and the second in October of that year.
There is no single version of Linux but there are different distributions (also called distributions), usually created by community developers or companies who choose, prepare and compile packages to include. All distributions share the Linux kernel (albeit in different versions and often custom), but differ from each other for the “software park”, i.e., packets prepared and selected by the developers to distribute itself, the management system software and support services and maintenance offered.
There are distributions executed directly from CD without requiring installation on your hard disk, like Knoppix and Daughter are called distributions or live desktop CD. For others, you can perform the installation from USB stick.