Chapter 1 ■ Starting Linux Command-Line adminiStration
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The initiative by Torvalds didn’t stand on its own. Many other software developers had already started
initiatives to create free software for the UNIX operating system. The only thing that really was missing at that
moment was a kernel that was stable enough to go into production and offer a complete and free alternative
to the expensive UNIX operating system.
Open Source
Right from the start, Torvalds released his software as open source software—that is, software whose source
code is freely available to anyone. This brings a major benefit: other programmers have access to the source
code and thus it becomes much easier to fix issues in the code, with the result of getting code that is more
stable and reliable. This open source initiative fitted well into many other open source programs that were
a part of the GNU initiative. The acronym GNU stands for GNU is Not UNIX, which means that this is about
software written for the UNIX platform but doesn’t use UNIX licensing. This GNU initiative was a part of
the Free Software Foundation (FSF), which wanted to create free software for a better operating system
experience.
When it came to licensing, Torvalds released his software under the GPL. In those days, GPL stood for
GNU Public License, but nowadays it means General Public License. The details of this license are quite
complex, but in essence it means that software released under the GPL can be used and modified by anyone,
as long as the person modifying this software makes sure that his or her modifications will be released under
the GPL as well. In brief: once software has a GPL, it will always stay GPL software. This prevents companies
from making small modifications and then taking the software out of GPL and selling it for a lot of money.
In current Linux versions GPL still is very important. Most distributions consider it an essential property
of the Operating system and will refuse software that doesn’t comply with the conditions in the GPL license.
By being so strict about the licensing, Linux distributions ensure that the software that is released as Open
Source software will always stay Open Source software. Some distrubutions do also allow non-open source
softare to be included, such as binary code for specific firmware. You will notice a different philosophical
approach in this between the different distributions.
The First Distributions
Apart from the Linux kernel, lots of other programs were available under the GPL as well. In the early days,
people who wanted to start using Linux had to go on the Internet and download these software programs
themselves. Often, after downloading them, they even had to compile them for themselves. This compilation
process was necessary to convert the program files, which were published as source code files only, to
executable programs that users could execute on their computer.
Software compilation is not very easy to do, and for that reason, different people started to create
collections that consisted of the Linux kernel and some other useful programs. One of the first persons to
do so was Patrick Volkerding, who started his Slackware distribution in 1993. In those days, this distribution
consisted of different software categories, all put together on no fewer than 43 diskettes. Volkerding was
perhaps the first who made a successful Linux distribution that started to get used on servers all around the
world, and his Slackware distribution still exists, although new releases are not published very frequently.
Linux Turning Mainstream
The years between 1993 and 1998 marked the rise of the Linux operating system. One of the most important
reasons that it took of so rapidly, is that it provided a very affordable alternative for the expensive UNIX
operating system that was used on many mission-critical server systems. In the early days of Linux, no
support was available, but that didn’t prevent scientists at different institutes around the globe to start
working with it. Linux also acquired huge popularity rapidly in educational environments. Due to this
popularity, during this period the most important Linux distributions were created.
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