The Three Giants of Linux
The Linux ecosystem is a complex entity. On one hand everyone gets along and benefits from work done by others, while on the other there's often animosity and conflict between distributions and their communities (remember when Ubuntu came along?).
People often complain that there is simply too much choice in the Linux world and that we'd all be better off if there was just one, or two. However, nothing could be further from the truth.
The multitude of Linux distributions exists for a reason. They exist because not one single distribution can satisfy the desires of every user on the planet. Different people like different ways of doing things. Not only that, the distribution that one might want to use for a server won't necessarily suit a laptop. So thankfully there are thousands of distros to choose from.
In the Beginning
Of course it wasn't always that way. GNU had a beginning, Linux had a beginning and so also the first distribution had a beginning.
That's right, the first official distribution was called MCC Interim, back in February of 1992. It was the first distribution able to be installed on a computer, shipping the Linux kernel with a GNU user-land. Within that same year, a new (and popular at the time) distribution was created, called Softlanding Linux System (known simply as SLS), which in turn spawned Slackware, created by Patrick Volkerding. To this day, Slackware remains the oldest surviving Linux distribution.
By the time Slackware came onto the scene, there were already half a dozen Linux distributions. A few months later however, on August 16th 1993, one of the most important was about to emerge all on its own, which today takes the crown for the oldest surviving independently developed Linux distribution. Meet Debian. Debian was not a fork of any previous work, but an independent project in its own right, created by Ian Murdock. Entirely community driven, Debian remains the largest non-commercial distributor of Linux.
Almost one year after the birth of Debian, in 1994 the third and final member of the most influential distributions arrived on the scene, Red Hat Linux. This distribution was originally created by Marc Ewing but shortly thereafter merged with Bob Young's company, ACC Corporation, creating Red Hat Software. From the very beginning, Red Hat Linux was designed with the corporate world in mind. It was and is a commercial implementation of a Linux distribution, built upon free software.
Together, these three distributions are the pillars of Linux, the giants. They have each lead the way, creating technologies and methodologies which we take for granted every day. They have forged the path to make Linux distributions what they are today.
Not only are they the three oldest surviving, they have each in turn spawned an entire range of operating systems. Certainly there have been other important independent distributions along the way such as Arch, Crux, Gentoo (from Enoch), Linux From Scratch, Puppy, ROCK, Tiny Core, Yoper and a great number of others. However, the following image of Lundqvist and Rodic's GNU/Linux distro timeline illustrates just how influential these three distros have been.
According to DistroWatch, sixty-six distributions have been created from Slackware. Red Hat Linux has spawned around forty directly (with another eighty or so coming from Fedora), while grand daddy Debian makes it two hundred and fifty! At the end of the day, the majority of Linux distributions which exist today are at some point a derivative of one of these three.
These three distributions really couldn't get much more different. Of course the core is the same in each; a Linux kernel, GNU user-land as well as various desktops and applications. Aside from the required similarities, how do these distributions differ? As you'll see, each one encompasses a unique perspective, which shows just how important diversity is!
Slackware - The Dictatorship
In many ways, Slackware was and is a one man show. Patrick Volkerding created the distribution and he still controls it today. Certainly, he has a fantastic team surrounding him and a dedicated community behind him, but he is the one who calls the shots.
The distribution itself revolves around simplicity and tries to remain as Unix-like as possible. It does not heavily patch its packages, rather shipping products which resemble upstream as closely as possible. Slackware leaves the user in charge and gets out of the way. It traditionally doesn't make heavy use of a package manager and while it can install, upgrade and remove packages, it does not track or manage dependencies. This task falls to the system administrator (or user), and is one of the most striking differences between Slackware and the other two.
For these reasons, it is often considered a "harder to use" distribution, but fans of the distribution see these as necessary tools of power and flexibility. Nevertheless, Slackware is well regarded among the community and very stable.
Recently it gained support for both 64bit and ARM architectures, but prior to this was heavily focused on 32bit only. It only supports one major desktop environment, KDE, although others such as GNOME are supported by the community.
While many other newer distributions are adding additional layers of complexity to make things easier, Slackware is staying true to its UNIX roots, offering a simple yet powerful, highly configurable system. For more insight into Slackware, take a look at our interview with developer Eric Hameleers.
Debian - The Proud Community
Debian has a long, proud history. It is comprised of a worldwide community of volunteers, including over one thousand developers all working together to create the best possible operating system from free software. Debian is unique in that it is ruled by its constitution, social contract, free software guidelines and policy documents. As such, the structure of the organization is very official, with an elected leader, secretary and technical team. Leadership elections are held every year.
Unlike Slackware, the Debian leader does not have absolute power. In fact by way of a general resolution, developers are able to reverse decisions, remove the leader and even make changes to the constitution. Developers may also vote on important issues affecting the project (such as whether to include binary firmware).
Debian revolves around a fully blown package management system, comprising several important components. This system not only performs expected tasks such as installing and removing packages, it also automatically handles dependencies. This was a core component of Debian very early on, setting it apart from all other distributions in its time. Debian uses the famous .deb package format as opposed to the plain tarballs of Slackware and RPMs of Red Hat. In many respects, package management is key to Debian. The project has strict guidelines on developing software, and finely tracks packages to ensure a consistent system state over upgrades. The utmost importance is put on ensuring packages are built and work correctly.
All of Debian's releases are named after characters from the Pixar film, Toy Story. Debian is known for the high quality of their releases, which are often delayed. The project maintains three main branches, stable, testing and unstable (called Sid). Although the official desktop is GNOME, the project supports just about every desktop and window manager in existence. This is another stark contrast to Slackware, which only officially supports KDE.
Also unlike Slackware (which until recently only supported a single architecture), Debian supports eleven different architectures with another five on the way. It also comes with over 25,000 packages, ready to be installed via their package management system. Due to its reliable nature and wide support for numerous architectures, Debian is widely used on desktops, servers and embedded systems.
When you consider the scale of what the Debian project achieves, it is truly remarkable. This solid foundation and structure has contributed greatly to Debian's success and made it an excellent choice for derived distributions such as Ubuntu.
Red Hat - The Commercial Presence
From the get-go, Red Hat Linux has been about commercialization of Linux. To this end, it has been a great success, selling subscriptions for support, training and integration services. A majority of its popularity owes to the fact that it is widely used as the supported Linux distribution of choice in a corporate environment. There are hundreds of Red Hat Linux courses available and for the longest time "Linux" was often synonymous with "Red Hat."
It's important to make the distinction between Red Hat's official commercial Linux offering, Red Hat Enterprise Linux (RHEL), and others such as Fedora. RHEL is only available in binary form when purchased from Red Hat, unlike our two other distributions. The entire source code for the operating system however, is entirely free and from this numerous other distributions have sprung (such as CentOS).
The majority of the development work on RHEL is done by Red Hat employees. Unlike Slackware and Debian, this distribution's development is primarily founded in the Red Hat sponsored community distribution, Fedora. Although a stable and exciting distribution in its own right, Fedora is essentially the testing ground for new technology which will find its way into Red Hat's commercial offerings.
Unlike Debian, Red Hat gained a comprehensive package management system rather late in the game. At its core however, it revolves around packages in the RPM format, which are handled by various low level tools. Today, installing packages on Red Hat is as painless as it is on Debian, with support for dependency tracking and many fancy features to ensure a consistent state.
Red Hat is the leading contributor to both the Linux kernel and X.Org. It is also responsible for many other great pieces of software which we take for granted, such as D-Bus, HAL, Policykit, NetworkManager, PulseAudio (cough cough), Liberation Fonts, Palimpsest and really far too many to mention.
Red Hat is a great advocate for free software and have released a Patent Policy which they use to the benefit of free software. Their business model has been a huge success and is often used as a prime example of the ability to make money from free software.
Perhaps you never realized just how unique the history of Linux distributions is, or how all of these distributions came about. Hopefully this has provided at least some insight into our rich heritage. Whether it is a package management system, modern applications, culture or philosophies, the existence of these distros has been invaluable in shaping the Linux environment as we know it today. Each one of them continues to play a very important role in the continued success of our platform of choice.
Despite their sizable differences, these giants are more popular today as they ever have been. It's also refreshing to know that even though there are hundreds of active distros available, none has come along yet which has been able to knock any of these three from their place. It's obvious that these three distros still have a lot to offer, even with their differences. In fact, perhaps it's because of their differences that they remain so strong. There's no such thing as one size fits all in the computer world and we should be celebrating the differences that exist, along with the choice and freedom that brings.
Thanks to these three distributions, we have a rich culture and history to build upon for years to come.
Nanos gigantium humeris insidentes. We stand on shoulders of giants.