Linux

In the early 1990s, the UNIX world was fragmented between expensive commercial variants (AT&T System V, Sun Solaris, IBM AIX, HP-UX) and academic derivatives such as BSD, entangled in legal disputes. For teaching purposes, Andrew Tanenbaum had been offering since 1987 the Minix system, limited but aimed at students. It was on Minix, installed on an Intel 80386-based PC, that the young Finnish student Linus Torvalds — then twenty-one years old and enrolled at the University of Helsinki — began writing his own kernel in April 1991 to make better use of the 386's protected-mode instructions. On 25 August 1991, he posted on the Usenet newsgroup comp.os.minix a famous message modestly announcing "a free operating system (just a hobby, won't be big and professional like GNU)". Version 0.01 of the Linux kernel was released on 17 September 1991, followed by 0.02 in October. Torvalds quickly integrated contributions from an international community of developers drawn to the open model. In 1992 he adopted the GNU GPL v2 licence, making the kernel legally compatible with the utilities from the GNU project launched by Richard Stallman in 1983. Together they formed complete distributions: Slackware (1993), Debian (1993), Red Hat (1994) and later Ubuntu (2004). Version 1.0 was released in March 1994, 2.0 in 1996 with SMP support, and 2.6 in 2003. A distributed development model took shape, which Torvalds systematised in 2005 by creating Git to manage contributions. Linux progressively became the dominant system in every computing segment outside the personal desktop. It powers the vast majority of web servers, the supercomputers of the TOP500 (all of them since 2017), Android smartphones since 2008 — Android being built on a Linux kernel — connected devices, home internet routers and most of the cloud (AWS, Google Cloud, Azure). It embodies the most spectacular success of free software and is still led by Linus Torvalds, who has made it one of the largest collaborative projects in human history.