GNU / Linux is an extremely powerful and versatile operating system with free license. It was created in 1991 by Linus Torvalds, when he was still a student at the University Of Helsinki, Finland.
Linux is not the product of a single company, is the result of the contribution of a large number of companies and groups of people. In fact, GNU / Linux system is a central component, which is transformed into many different calls distributions which change the appearance and operation of Linux.
Anyone is free to do many things in Linux it can be installed on all computers without paying anyone, give copies to friends, can study it, modify it, or create and sell their own distribution.
No need for antivirus which needs expensive licenses. Linux is very secure; there is almost no spyware and viruses on Linux. It is difficult for a malware to infect a Linux system.
GNU / Linux is more difficult to use than other OS such as Windows and has many more features. It takes sometimes to familiarize with a distribution such as CentOS, which comes with many programs already installed.
Commercial quality software to work with business documents, internet, networking, or graphics, is already free on most of the Linux distribution and ready for use. There are many thousands of programs that can be install and uninstall in a simple and easy way.
Linux As Servers.
Linux are very powerful for servers. It is simple to implement and very cheap, that is, it is a big saving for companies, such as data centre, which normally has to install thousands of servers and need to paid licences to for each servers.
The reasons what make Linux to be good for servers are:
Reliability Linux is stable and reliable for long periods of time even for huge workload.
Scalability Hardware and software can be easily added to the kernel by just compiling and loading the required modules on the kernel.
Affordability It is free and lots of tutorials are also free on the Internet (There a large Community of Linux Users for help).
Flexibility All server application can be easily hosted on Linux.