And by brief, I mean as short as possible. The Linux story has been written down over and over, so here are the basics for the few who have not already read or heard it:
In the beginning, there was UNIX. It was an operating system developed in the ’70s, that was originally meant to be a workbench for creating applications, growing from this into a multi-purpose (and multi-user) operating system. From UNIX, the minimal version MINIX was created, mainly for educational purposes.
Neither UNIX nor MINIX was free (as in freedom, more on that later), at the time. In 1983, a guy called Richard M. Stallman started working on what he called “a complete Unix-compatible software system called GNU (for Gnu’s Not Unix)”. He decided to give it away for free.
Fast forward to 1991. Linus Torvalds, a Helsinki computer science student and penguin enthusiast, has been working on something he called “a hobby project”, based on MINIX. He wanted to create a similar system, for his own education. Not surprisingly, he has named it after himself (who wouldn’t). It’s called the Linux kernel.
The last ingredient was fate (or luck, or divine intervention) so that these two people would find each other (there was probably a lot more elaborate effort and even more people involved, but your humble author was not there to confirm, besides, fate sounds a lot more interesting). Stallman’s GNU was nearly ready, it had all the tools and components, except for one thing, the kernel (the bit that sits between hardware and applications, in very rough terms). Stallman’s kernel, the GNU Hurd was coming along slowly and was nowhere near production grade.
Combining the GNU tools with the Linux kernel seemed like a good idea at the time (and in fact it still does). GNU/Linux was born.