Debian: what does this Linux kernel offer?

In 1992, the Canadian software developer Peter MacDonald published the Softlanding Linux System (SLS), one of the first known Linux distributions. In addition to the standard GNU tools and TCP/IP, this software collection based on the Linux kernel also integrated the X Windows system for the first time, making it possible to be used as a framework for the development of graphical interfaces. SLS quickly became the most famous distribution on the market, but the Linux community were left disappointed because of the high rate of errors.

Two of the biggest critics of SLS, the computer scientists Ian Murdock and Patrick Volkerding, reacted by deciding to develop their own, error-free systems separately. While Volkerding decided to optimize SLS, releasing a new version under the name Slackware the following year, Murdock started work on an entirely new project. Inspired by SLS and funded by the Free Software Foundation, he assembled a team of around 60 developers and eventually published the first stable version of Debian GNU/Linux in 1996.

Debian is a free software distribution for computer systems with wide-ranging hardware architectures. Since the complete package relies on the Linux kernel system developed by Linus Thorvalds, and uses the basic system tools of the GNU project, the alternative full title Debian GNU/Linux is often used. Even today, the communal Debian project is being further developed by more than 1,000 official developers from all over the world. As one of the oldest and most widespread collections, Debian now includes more than43,000 ready-to-use software packages and is considered a universal operation system solution. Debian is regarded as one of the most influential distributions, and is the basis of many newer distributions – including the very popular Ubuntu. Since Debian 6.0, there’s been an additional variation published that’s based on a FreeBSD kernel.

After updated versions with new functions were released annually at the start of the project, Debian’s advancement has slightly slowed, with new versions being released roughly every 24 months since the turn of the century. The first version to be officially released was actually 1.1 and not 1.0. This happened after a manufacturer had wrongly released an unauthorized version with the title Debian 1.0, and so 1.1 was the best way to avoid any confusion. Even back then, the published distribution version had a code name which was based on a character from the animations film Toy Story: Buzz. The story behind this is quite simple: at that time, Bruce Perens, who also worked as a studio tool developer for Pixar (the film studio responsible for Toy Story), had just taken over the direction of the Debian project.

As a rule, each Debian version runs the same life cycle: from the test phase, to the eventual official release, up until the release of the next version. In some cases, the cycle begins with what’s known as an experimental phase, which occurs when changes are planned for the new version that could have a big effect on the system as a whole. In this phase, the version doesn’t usually contain the full collection of applications, but instead just a few packages that are still in their alpha stage and can’t be uploaded to the unstable version. The following list shows all the usual stages of a Debian version.

• Unstable: in the unstable phase, no complete distribution versions are tested. Instead, new versions of packages and programs are tested before they’re integrated into the complete version in the next phase. The duration of the test can last any length of time, from just a few hours up to ten days, depending on the package. If no serious errors are found (‘RC bugs’), then the program enters the testing phase. Since the end of 2000, this version status has functioned under the codename Sid (another reference to Toy Story – Sid is the child next door who loves to destroy toys for fun).

• Testing: the testing version of a program is seen as an official candidate for the version that could be published in the future. In the testing phase, new application packages are integrated to ensure that the version is constantly evolving. Several months before release, the testing version is frozen (‘freeze’ phase). From this point on, the focus is just on eliminating as many errors as possible. Once all serious errors are eradicated, the release takes place and the testing version becomes a public, stable version.

• stable: stable is the term used for a current, up-to-date release of the Debian version. With the exception of security updates, the current software packages contained within this stable version won’t undergo any further changes. This makes the stable version the ideal choice for use in server systems which need to run reliably over a long period of time.

• oldstable: once a stable version has been superseded, it becomes known as an oldstable. The Debian developers recommend updating your version to the new stable version as soon as this happens, but they continue to offer security updates for an oldstable version for one year after release of the new stable.

Since Debian 6.0, ‘Squeeze’, there now exists long-term supportfor newer release versions through the newly founded project Debian Long Term Support. The purpose of this is to provide up-to-date, stable versions with security updates for up to 5 years.

Debian itself does not make any demands on the hardware it is required to run on, making the distribution a universal system solution. The only thing that Debian requires to run is the Linux or FreeBSD kernel, as well as the GNU tools. Meanwhile, the GNU/Linux distribution runs on every architecture or platform on which the respective system kernel and tools, such as the library libc, the compiler collection gcc, and of course Debian itself, have been ported (made available). The number of officially supported architectures has increased considerably over time, and in Debian 8.0, there are ten main architectures already, including various sub-architectures:

For more information about other supported architectures, you can head to the official Debian portlist site.

Debian is head and shoulders above any other Linux distribution for its absolute individuality. As one of the oldest collections still active today, its complete set of functions and supported hardware and software is unrivalled. Most impressive is the package management with dpkg (Debian Package Manager) as well as the constant testing of various applications and architectures by the engaged community, which helps to ensure that you can install Debian on numerous systems and platforms and use the programs and tools you want. The current Debian version contains more than 43,000 free software packages. And you can also make use of proprietary programs running on Linux or FreeBSD.

The wide-ranging community is always on hand to help with problems, offering the kind of support that you might need to pay for with other systems. But it’s not overly necessary to provide help and support right from the installation stage, because, despite the complexity of the distribution, it’s very intuitive and quick to get started with. The same is true of system upgrades, which also work through the package system dpkg. But if a program doesn’t work as expected, you can send an error report directly to the official error database, and you’ll receive a notification as soon as the problem has been resolved. If you’re a developer yourself, you can work on a solution on your own, thanks to the open source properties of almost every component.

The cooperative work of numerous community developers pays off when it comes to security as well: if security vulnerabilities are discovered, it’s usually only a couple of days before new, corrected packages are uploaded. But security gaps like these are usually a rarity, because the vast majority of them are discovered in the testing and development phase, and are rectified before the release of a new stable version. The intensive test phase also gives the Debian system a high level of stability, meaning that it almost never crashes.

The people responsible for the Debian project also attribute great importance to encryption: by using packages of the open source security software GnuPG, as well as the proprietary pendants PGP, e-mail content can be protected, which can then be combined with an SSL/TLS certificate. This provides optimal protection for the sending and receiving of electronic messages. Authenticated and encrypted connections to other machines can also be established via SSH (Secure Shell), which can communicate via the network protocol.

Despite all the positive aspects Debian offers, there are, as with any system software, certain points of criticism. It’s important to note that, despite its rapid installation, the subsequent configuration of the distribution is very difficult and can only be mastered with the appropriate know-how and experience. Implementing special hardware components such as a printer, for example, and the installation of software packages without script, can be particularly challenging for beginners.

In addition, the lack of support for some of the widely used commercial applications is often criticized. Even though Debian does deliver a huge number of software packages, many of the proprietary programs like the Microsoft Office applications Word, Outlook, and Sharepoint are not available for GNU/Linux distributions. This means that users are limited to alternative applications like LibreOffice or Alfresco. Since it’s only the programs running in their stable version that receive security updates, it could also be the case that these are no longer up to date, either.

The Debian project faces similar problems when it comes to hardware: very current architectures and devices, as well as those that are dependent on complex drivers, are often only supported in later versions. Lastly, the Debian developers unfortunately have their hands tied when a manufacturer puts its foot down, meaning that some hardware components – just like with ports for programs and tools – simply can’t be used.

To reduce Debian to a specific application area wouldn’t do justice to the system – the various hardware architectures supported, plus the tens of thousands of applications ready for installation, and an absolutely secure and stable system, make the Debian distribution a true all-rounder. But due to the complexity of the system, and the fact that some software isn’t always up to date, certain alternatives like the derivative Ubuntu represent a better choice for computers at home – especially for newcomers to Linux. The real strength of Debian lies in its use as a server system. The respective stable version, including long-term support, is ideally suited to any project that needs the backing of a contact and a practically error-free system.

If you’re interested in using the GNU/Linux distribution, you can download the installation file for the current Debian version on their official homepage. You can also find a test version, which you can use to run Debian from a CD/DVD disk or a USB stick, without having to install files onto your device first. For more information on versions, installations, and uses of Debian, the Debian Wiki, available at wiki.debian.org or the Debian forum can be useful tools.