Linux is a stable and secure operating system. The operating system is open-source and free. However, there are many companies that sell support for Linux, and maintenance is typically the source for most of the cost comes of maintaining an operating system.
Background
Limited to 16 concurrent users at his school’s computer, Linus wanted a computer but did not want to use MS-DOS. Eventually, he stumbled across a mini-Unix which ran on an old DOS computer called Minix. It didn’t do anything except teach students how operating systems were programmed. Torvalds installed Minix and started to tinker.
“In the summer of 1991 – just six months after he got his first PC – Linus found he needed to download some files. But before he could read and write to a disk, he recalls, “I had to write a disk driver. Then I had to write a file system so I could read the Minix file system in order to be able to write files and read files to upload them,” he explains, as if it was the only reasonable thing to do. “When you have task-switching, a file system, and device drivers, that’s Unix” – or at least its kernel. Linux was born.”
Wired, The Greatest OS That (N)ever Was, https://www.wired.com/1997/08/linux-5/
Linux Grows Up
Subsequently, Linus’ operating system evolved. He filled in missing pieces, learning along the way how to program an operating system. The project grew in scope as people from Minix contributed software, each building and reviewing the work of one another.
Eventually, somebody jokingly named the new operating system Linux, and the name stuck.
Linus licensed the operating system under Richard Stallman’s GNU General Public License, or GPL. He also adopted Linux to run with GNU software, including the emacs word processor, alleviating the need to write his own applications.
Linux has grown into one of the world’s most robust and important operating systems, powering much of the internet.


(but, for the record, we still love ya’ Linus)