Linux — Linus Torvalds' 21-Year-Old Announcement

On 25 August 1991, Linus Torvalds, a student in the computer-science department at the University of Helsinki, posted to the Usenet newsgroup comp.os.minix:

Hello everybody out there using minix —

I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones.

"Just a hobby, won't be big and professional"—he really wrote that.

Thirty-five years later, the same author surely knows it became larger, and considerably more professional, than he had any intention of making it.

Starting from Minix

Linus had been programming since childhood, beginning on a Commodore VIC-20. In 1991, his university coursework included Andrew Tanenbaum's Operating Systems: Design and Implementation; bundled with the book was a teaching OS called Minix.

Minix was a small UNIX-like system designed to teach. Its source could be read and modified, but its licence was tightly framed for educational use. Commercial reuse, or distributing significantly modified derivatives, was not permitted.

Linus wanted a real OS for his own Intel 80386, then the high end of personal computing. Minix did not exploit the 386's capabilities—protected mode, virtual memory, true multitasking.

So he started writing a terminal emulator that exercised task switching. A file system came next, then I/O. After a few months he realised he was, in fact, writing an operating system.

Choosing the GPL

In January 1992, Linus relicensed Linux under the GNU General Public License. Before that he had used a more restrictive licence of his own.

That choice was decisive. The GPL—copyleft—requires that anyone redistributing the software, modified or not, do so under the same licence. Linux could not be enclosed by a commercial vendor and turned into a proprietary product.

Patches began arriving from developers around the world. By the end of 1992 there were already hundreds of contributors.

Big, and Professional

• 1994: Version 1.0.
• 1996: Tux the penguin became the mascot.
• 1998: Major commercial vendors (IBM, SGI, others) announced Linux support.
• 2003: SCO sued, alleging IP infringement; SCO ultimately lost.
• 2007: Google adopted Linux as the kernel of Android.

By 2026: more than 80% of the world's web servers, 100% of the TOP500 supercomputers, the billions of Android devices, Tesla's car software, NASA's Mars helicopter Ingenuity—all run Linux.

The 21-year-old who wrote "just a hobby" is now a fellow of the Linux Foundation, and still personally signs off on each release of the Linux kernel.