Linux and Linux distributions

While being a student at the University of Helsinki. Linus Torvalds was frustrated by the licensing of MINIX.

MINIX: MINIX was released in 1987 as a minimal UNIX-like operating system. It was created by computer science professor Andrew S. Tanenbaum for students who wanted to learn the operating system principles. The complete source code of MINIX was freely available, but the original licensing terms prevented it from being free software.

In 1991, Torvalds began writing his own operating system kernel on MINIX, and he released his project, named Linux, as freely modifiable source code in the same year. The initial license for Linux wasn’t a free software license. Having learned about the GNU project and about version 2 of the GPL which was released in June 1991, he relicensed Linux under the GPLv2 in 1992. While the developers in the GNU project were working on a complex microkernel, Torvalds had created a monolithic kernel that was faster than the one the GNU people were building. He also involved the community to collaborate on Linux.

Eric Raymond, who had been contributing to GNU Emacs, wrote a paper called “The Cathedral and the Bazaar”, explaining the development process that led to Linux, using one of his own free software endeavors “fetchmail” as an example.

I believed that the most important software —operating systems and really large tools like the Emacs programming editor— needed to be built like cathedrals, carefully crafted by individual wizards or small bands of mages working in splendid isolation, with no beta to be released before its time.

Linus Torvalds's style of development —release early and often, delegate everything you can, be open to the point of promiscuity— came as a surprise. No quiet, reverent cathedral-building here —rather, the Linux community seemed to resemble a great babbling bazaar of differing agendas and approaches (aptly symbolized by the Linux archive sites, who'd take submissions from anyone) out of which a coherent and stable system could seemingly emerge only by a succession of miracles.

The fact that this bazaar style seemed to work, and work well, came as a distinct shock. As I learned my way around, I worked hard not just at individual projects, but also at trying to understand why the Linux world not only didn't fly apart in confusion but seemed to go from strength to strength at a speed barely imaginable to cathedral-builders.

(Extract from The Cathedral and the Bazaar)

The essay was originally written in 1997, but later it also became a book. In an epilog, we learn how the Cathedral and the Bazaar inspired Netscape to release the source code of its browser, Netscape Communicator in January 1998, which led to the creation of Mozilla. But we’re getting ahead of ourselves; let’s return to the early nineties.

The GNU operating system with a Linux kernel

University students working with UNIX at their University, were looking for a UNIX-like system that they could run at home, but price was always an issue. In 1992, SUN Microsystems reduced the price of a SPARCstation workstation to just below $6,000; IBM’s RS/6000 model at that time was about $10,000. Those prices were much higher than the cost of personal computer, which amounted to about $2,000 for a decent setup. Originally developed to run on a PC, Linux allowed students to build their own UNIX-like system. Combining Linux with the tools of the GNU operating system on their own PC at home, resulted in a computer that was at least 1.5 times faster than the machines they were using at the University.

GNU operating system vs. Linux: Although we have gotten used to talk about the Linux operating system, it is more correct to talk about the GNU operating system with a Linux kernel. Much to the frustration of Richard Stallman, the industry and the media has gotten so used to the word Linux that there’s hardly anyone who still talks about the GNU operating system. When we talk about Linux, most of the times we implicitly refer to the GNU operating system.

In 1998, Forbes published some numbers about Linux:

Year Version Lines of Code Users
1991 0.01 10,000 1
1992 0.96 40,000 1,000
1993 0.99 100,000 20,000
1994 1.0 170,000 100,000
1995 1.2 250,000 500,000
1996 2.0 400,000 1,500,000
1997 2.1 800,000 3,500,000
1998 2.1,110 1,500,000 7,500,000

What happened? How did Linux become so popular in such a short time?

A killer app: Apache web server

Although initially designed for personal computers, Linux soon became the predominant operating system on servers. In 1995, a group of volunteers took the code of the NCSA web server, developed at the National Center for Computing Applications (NCSA), an American state-federal partnership, and released a new web server using a permissive software license. They named it Apache web server. According to Brian Behlendorf, one of the creators of Apache, the name was a pun on “a patchy web server” because they were building a server out of a bunch of software patches. The etymology of the name may sound condescending, but Apache has been the most popular web server since April 1996.

Apache web server made it much easier for organizations to roll out web based electronic commerce and it paved the way for mass communication. Its permissive license allowed Apache web server to be bundled with Linux. As such, Apache web server played a crucial role for Linux. Internet Service Providers (ISPs) discovered that using Linux on their servers was much less expensive than using Windows NT servers. Using Linux required some extra training and maintenance, but the total cost of ownership (TCO) was much lower. You could host multiple web sites from different customers on a single server, and thanks to the continuous effort of a growing community of Linux developers, Linux turned out to be more reliable, flexible, and extensible than any other operating system. For an ISP, the choice of Linux over Windows was a no-brainer.

It’s not a coincidence that the rise of the internet coincides with the rise of Linux. And with the rise of Linux came the first companies that made Linux distributions.

Distributing Linux

Linux was initially distributed as source code only, and later as a pair of downloadable floppy disk images, one bootable and containing the Linux kernel itself, and the other with a set of GNU utilities and tools for setting up a file system.

The installation procedure wasn’t trivial, and new tools were made available at a rapid pace, which led to the creation of Linux distributions. The two oldest distribution projects that are still active, started in 1993. Slackware was released in July 1993 by Patrick Volkerding. Debian was released in September 1993 by Ian Murdock. Both were based on the Softlanding Linux System (SLS) released in 1992. In October 1994, on Halloween, Marc Ewing released a Linux distribution which he named Red Hat Linux. In 1995, he joined forces with Bob Young who had founded the ACC Corporation, a company that sold Linux and UNIX software accessories.

On August 11, 1999, Red Hat Software went public on the NASDAQ stock market. It was the first Linux company that launched an Initial Public Offering (IPO). Red Hat acquired Cygnus Solutions in November of the same year, ensuring continuous support for Linux. In 2012, Red Hat would be the first billion-dollar “open source” company, reaching $1.13B in annual revenue during its fiscal year.


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