A Linux distribution is a selection of coordinated software around the Linux kernel , which in some cases is also a more or less adapted distribution kernel that is usually maintained in close coordination with Upstream itself . Usually, the term is limited to compilations that are largely Linux-typical, which does not apply to Android , for example .
Distributions in which GNU programs play an essential role are also referred to as " GNU / Linux distributions ". The naming with or without GNU name suffix is handled differently by the distributors depending on their position in the GNU / Linux name dispute .
Almost every distribution is built around a package manager ; This means that all components of the installation are available as packages and can be installed, uninstalled and updated using the package manager. The packages are held online in so-called repositories .
A Linux distribution is put together by his distributor. Usually this person selects programs for which he has the necessary rights, adjusts them more or less, packages them in his package manager and offers the result as a distribution. Usually only a few programs are written by the distributor himself, e.g. B. usually the distribution installer . The distributor can be a company or a group of volunteers from around the world. He can also offer commercial support.
The point of a distribution is to create a package of coordinated software. The central part is made up of the Linux kernel itself, as well as system programs and libraries. Depending on the intended use of the distribution, various application programs (e.g. web browser , office applications , drawing programs , media players, etc.) are added.
Linux distributions usually have a large number of programs ready for installation in the repositories. This is in conceptual contrast to other operating systems such as Windows and macOS , which in addition to the operating system itself only contain a few applications, but rely on the integration of programs from external providers, so-called ISVs .
Further tasks of the distributions are adapting the programs (by patching ), adding your own program developments (especially for installing and configuring the system such as apt , Synaptic , YaST ) and (with a few exceptions, e.g. Gentoo) compiling and Packaging ( .deb , .rpm ) of the programs. Additional programs and updates are typically provided centrally via a repository , which is synchronized with the operating system via a package management system.
Even if distributions are by far the most common variant of Linux operating systems, Linux can also be operated without a ready-made distribution, for example with the help of Linux From Scratch . In the embedded systems market, which is important for Linux , distributions are not very common.
In addition to the Linux kernel, a distribution usually consists of the GNU software environment. This provides large parts of the basic basic system with the numerous system services (so-called daemons ) as well as various applications that are expected in a Unixoid system . Distributions that are also or only intended for desktop systems usually have a window system , currently mostly the X Window System . This is required for running a graphical user interface . Based on this, a desktop environment such as Gnome or the KDE Software Compilation is usually available, which, in addition to the pure user interface, also includes a selection of application programs .
In addition, a distributor usually adds numerous other applications. These are, for example, office packages , multimedia software , editors , e-mail programs , browsers , but also server services. In addition, there are mostly software development tools such as compilers or interpreters and editors.
Many software components of Linux distributions, e.g. B. the compiler GCC , come from the older GNU project. Even before Linux was developed, it had set itself the task of developing an alternative to the commercial Unix operating systems. Since the GNU Project's own kernel, GNU Hurd , is still under development, the Linux kernel is often used as a replacement. Therefore, the double name GNU / Linux is also common for a distribution (e.g. Debian ).
There are also Linux distributions that completely do without the GNU software components or an X Window System and instead use alternative software. These distributions, such as FreeVMS or Cosmoe , sometimes do not behave even remotely like a Unix system.
While proprietary operating systems are often sold through retailers , Linux distributions tend to be the exception. Most distributions can free from the Web site to download the provider. These are financed through donations, paid support or simply through the participation of volunteers. Only a comparatively few distributions are developed by profit-oriented companies and some are available through retailers. Numerous Linux distributions are also purchased, unnoticed by customers, as firmware on a device or even in larger machines or systems . It can be, for. B. machine tools , vehicles , household appliances , PLCs , measuring devices , mobile phones , modems , digital cameras , NAS or televisions .
Since Linux is just an operating system kernel , additional software is required to get a usable operating system. For this reason, the first Linux distributions appeared shortly after Linux was licensed by the GPL , when users who were not part of the direct development circle began to use Linux. The aim of the first distributions was to bundle the system with the software of the GNU project, for example, to form a working operating system. They included MCC Interim Linux , which was released on the University of Manchester's FTP servers in February 1992, and TAMU and Softlanding Linux System (SLS), which came out a little later. The first distribution available commercially on CD in 1992 was Yggdrasil Linux, developed by Adam J. Richters . In 1993 Patrick Volkerding published the distribution Slackware , which is based on SLS. It is the oldest Linux distribution still active today. Also in 1993, about a month after the release of Slackware, the Debian project was launched, which, unlike Slackware, is jointly developed. The first stable version came out in 1996. In 2004 Canonical released the Debian-based, later very popular Ubuntu .
The first users were still familiar with free software from before the 1980s and valued Linux because they again had the exploitation rights to the software they were using. Later users were Unix users who initially used Linux primarily for private purposes and were particularly pleased about the low price. The first distributions were created for convenience only, but today they are the usual way for users and developers to install a Linux system. The Linux distributions are nowadays developed and operated by developer groups as well as by companies or non-profit projects.
The question of which distributions are particularly popular is difficult to answer. In German-speaking countries, Ubuntu, Debian, openSUSE and Knoppix are mentioned more often outside of the IT press. In addition, Fedora should be mentioned, which is developed by the listed US company Red Hat .
Types of distributions
Since distributions are practically their own products , they compete with each other on the market and try to differentiate themselves from one another on the one hand, but not to give other distributions too much advantage on the other. Therefore all distributions differ; but there is hardly anything for which every distribution cannot be adapted. The only exceptions are special systems, such as software in the embedded area.
Some distributions are specially optimized for one use case. For example, there are systems specifically for use in educational institutions with specialized software and mostly a terminal server system, which means that only a powerful computer is required and older hardware is otherwise sufficient. Examples are Edubuntu or DebianEdu . There are also systems specially designed for outdated computers that have a smaller range of functions and have low system requirements. Examples are Damn Small Linux or Puppy Linux , which are only 50 and 100 MB in size.
There are specially optimized Linux distributions for smartphones and tablets . In addition to telephony and SMS functions, they offer various PIM , navigation and multimedia functions. It is typically operated using multi-touch or a pen. Linux-based smartphone operating systems are mostly developed by a corporate consortium or a single company and in some cases differ very greatly from the otherwise classic desktop, embedded and server distributions. Unlike in the embedded area, Linux-based smartphone systems are not limited to a specific device. Rather, they serve as an operating system for devices of very different model series and are often used across manufacturers.
The architecture of many Linux-based smartphone and tablet operating systems such as B. Aside from the Linux kernel, Android has little in common with classic Linux distribution concepts. Whether Android, as the most important Linux kernel-based smartphone operating system, should also be classified as a Linux distribution is a matter of controversy. Typically only a small part of the otherwise common GNU software environment and tools are used. Although Android itself is open source, it is usually delivered with the proprietary Google Play services , as Android itself does not contain the often requested Google Play Store . Since this uses uncontrolled proprietary binary software, Richard Stallman and the FSF are very critical of Android and recommend the use of alternatives. The UNIX-like services and tools mostly used on Linux are partially replaced by a Java runtime environment . This creates new programming interfaces that can be emulated or implemented on any other platform. Despite large discrepancies, Android is classified by some on the basis of common properties with embedded Linux distributions among Linux distributions. Other Linux-based smartphone operating systems such as Firefox OS , Ubuntu for phones , Maemo , Tizen , Mer , Sailfish OS and MeeGo use larger parts of the classic GNU software environment, so that these can sometimes be more easily supplemented with classic Linux applications and thus more like Linux distributions in the classic sense.
While the market shares of previously widespread mobile platforms such as Apple's iOS , Microsoft's Windows Mobile and Nokia's Symbian OS fell, Android was able to gain market share. Since the end of 2010, Linux systems have taken the lead in the rapidly growing smartphone market. Together they had a market share of at least 45% in July 2011. Android is currently by far the most popular Linux distribution for smartphones. The market share in May 2016 was 78%.
Linux is a popular operating system in embedded systems. Corresponding distributions are usually highly specialized because they are designed for a few, specific tasks. In most cases, there is no or only a very simple graphical user interface to be found. Often these are real-time systems . They usually bear little resemblance to PC distributions.
Live systems that boot from CD, DVD, USB and other media are a specialty . Initially, it was only about specialized distributions that were supposed to demonstrate the functional scope of Linux, but now it is common practice among Linux distributions to use the standard scope in the form of a live CD or DVD or a live USB memory stick to offer. Some of these systems can also be installed directly from the medium.
Live systems can be started as complete Linux without writing to the hard drive and without changing the existing configuration of a computer. In this way, the corresponding Linux distribution can be tested safely on a computer. Live systems are also ideal for data recovery and system analysis, as they are independent of the configuration of the existing system and thus cannot be affected by possible infections from worms and viruses.
Linux distributions alongside other operating systems
Most Linux distributions can be installed on the same hardware in parallel with other operating systems. Another Linux distribution, another Unix- like operating system such as macOS or Solaris , or Windows can be considered as such . In principle, there are two different approaches:
In a multi-boot configuration, two or more operating systems are installed in parallel on different hard disk partitions. Installation programs of modern Linux distributions can usually recognize operating systems that are already installed and independently set up a multi-boot configuration. After installation, you can choose which operating system should start during the boot process using a boot loader or boot manager .
If the operating systems are often used at the same time, it is possible to U. rather a virtualization solution. A distinction must be made between the host and guest system. The former is actually physically installed on the hardware. Within this a virtualization software such as VirtualBox or KVM is used. This emulates all the hardware required for the guest system or offers direct access to the actual hardware of the computer through a security system. Since this is necessary in such a configuration for the simultaneous operation of both systems, it can lead to speed losses.
Differences between individual distributions
Even if one disregards special distributions, common Linux distributions also differ in some points.
For example, some advanced distributions don't have an installer, just a live CD that provides the tools necessary for manual installation (e.g. Arch and Gentoo ). Most, however, offer an installer in the form of a wizard . Some offer a wizard, but require preliminary work, such as partitioning (e.g. Slackware). The rest of the configuration is usually the same as the installation method. With some systems you have to change the configuration files i. d. Usually edit directly while others provide tools for the most important options.
Another important point is the free availability. A few distributions cost money ( e.g. RHEL ) while most are free.
Distributions also differ in the number of supported architectures (Gentoo and Debian are particularly diverse). The type and scope of the documentation also play a role. Some products come with manuals ( e.g. RHEL ), while most of them are only available with documentation on websites. Some distributions do not have official documentation at all and prefer to have it maintained by the users - e.g. as a wiki . Commercial distributors also usually offer official support , which, however, must be paid for as a service. There are also differences in licensing policy. Some systems only have free software in their repositories (particularly consistent, e.g. Parabola ), while others also include unfree software . As a compromise, repositories with proprietary software are often offered, but they have to be added manually to the package manager (Debian and Ubuntu, for example) or an exception is made for particularly important programs (Ubuntu, for example). Paid software is almost never included. A further distinction is to be made between community distributions (e.g. Debian) and those backed by companies (e.g. Ubuntu). The update cycles also play a role. They range from rolling releases (e.g. Arch, Gentoo and Debian Unstable) to four-year update cycles with guaranteed ten-year support for a version (RHEL). The number of software in the repositories is also important. Depending on the target group of a distribution, the size and expertise of the users also vary.
Compatibility between the distributions
The differences between the distributions often affect their compatibility.
Early on in the history of distributions, concepts emerged to simplify the installation of additional software. In most cases, software should be provided in the form of compiled packages and a mechanism should be provided that can resolve functional dependencies between installed and downloaded packages. The resulting package management systems each work with their own package formats, for example RPM or dpkg . Many Linux distributions have their own software management with their own binary packages, some of which are incompatible with other distributions.
The criticism of the principle of Linux distributions starts at this point, among other things. Since not every software project and not every software developer has the knowledge and resources to provide software for every single Linux distribution, often only the source code is published. However, creating executable applications from the published source code is potentially a complicated and error-prone process that can be too complicated for many users. These then often remain dependent on or limited to the software supplied by the distribution. However, providing the source code as a software delivery method is not an option for providers of commercial software who want to deliver software in binary format, which is why they have to serve the multitude of distributions and their package formats with specific packages, which means a lot of additional work. In the corporate environment, therefore, only a limited selection of distributions has a chance as a general work platform.
Another important standard is POSIX . In contrast to the LSB, it goes beyond Linux and is intended to form a standard for all Unix-like operating systems. POSIX is not compatible with the LSB. Linux distributions usually adhere to much of the norm. However, there is currently no distribution that is officially certified as POSIX-compliant.
To prevent the distributions from diverging further, the Free Standards Group (now Linux Foundation ) was founded with the aim of promoting appropriate standards between distributions. The best known is the Linux Standard Base to promote the binary compatibility of the distributions. The various distributions implement the LSB with varying degrees of strictness. It defines matching binary interfaces (called " ABI ", for Application Binary Interface ), some details on the internal structure and a package system (here RPM ) that must be supported for the installation of software from other providers.
However, the practical meaning of these rules is only limited. The one-sided commitment to the RPM package format is sometimes questioned after the dpkg format has gained widespread use in recent years through Ubuntu or Linux Mint . Because most distributions that use dpkg are based directly on Debian , their packages are often installable in other distributions that are also based on Debian. On the other hand, all distributions derived from Fedora (or Red Hat Linux ), OpenSUSE and Mandriva rely on RPM. It is entirely possible with some restrictions - e.g. B. using the OpenSuse Build Service - to create RPM packages that can be used on all these distributions.
Another standardization is the Filesystem Hierarchy Standard , which is supposed to enable a common naming of some file and directory names and a consistent structure of the base directories. However, details are not regulated here either, which previously caused incompatibilities. Other problems arise only when applications are firmly integrated into the system directory tree. It is required by the Linux Standard Base .
Alternative approaches to program dissemination
There are some alternative approaches to the model of central software distribution via the distributions and their repositories . Projects such as Autopackage , Zero Install or the Klik successor PortableLinuxApps try to create a uniform, but decentralized, distribution-independent, binary software distribution option, but so far have in fact not achieved any relevant distribution or support from the Linux community .
One step in this direction was the introduction of a software center in Ubuntu in 2011 in order to be able to significantly increase the number of applications, as the distribution model only scales to a limited extent.
In 2012 the kernel developer Ingo Molnár also emphasized the necessity of providing such a decentralized, scalable and distribution-independent software distribution method; the lack of such a mechanism is one of the core problems of the Linux desktop.
- Johannes Plötner, Steffen Wendzel : Linux. The comprehensive manual. 4th edition. Galileo Press, Bonn 2010, ISBN 978-3-8362-1704-0 .
- Michael Kofler : Linux 2010: Debian, Fedora, openSUSE, Ubuntu. 9th edition. Addison-Wesley, Munich 2009, ISBN 978-3-8273-2158-9 . (up to the 8th edition under the title: Linux. Installation, configuration, application. )
- Distribution overview with ranking lists on DistroWatch.com
- List of live CD distributions
- Linux Distribution Chooser - an auxiliary tool for choosing between various popular Linux distributions
- Repology.org - search engine for software packages and their respective versions in various repositories
- ^ A Brief History of Debian - A Detailed History. Debian Documentation Team, accessed August 8, 2016 .
- ↑ Releases - Ubuntu Wiki. Canonical, accessed August 8, 2016 .
- ↑ a b Chris Hoffman: Android is Based on Linux, But What Does That Mean? ( English ) May 12, 2014. Retrieved on April 23, 2015: “ Android may be based on Linux, but it's not based on the type of Linux system you may have used on your PC. You can't run Android apps on typical Linux distributions and you can't run the Linux programs you're familiar with on Android. Linux makes up the core part of Android, but Google hasn't added all the typical software and libraries you'd find on a Linux distribution like Ubuntu. This makes all the difference. "
- ↑ a b Ryan Paul: Dream (sheep ++): A developer's introduction to Google Android ( English ) In: Ars Technica . February 24, 2009. Retrieved April 3, 2013.
- ^ Adrian Kingsley-Hughes: The death of the Linux distro ( English ) In: The death of the Linux distro . CBS Interactive. February 14, 2012. Accessed on September 19, 2012: “Take a look at how Android has become the dominant Linux distro on mobile platforms. [...] So again, while B2G is essentially a Linux distro, people will come [...] "
- ↑ Jeff Hoogland: Six Signs Android really isn't Linux ( English ) Thoughts on technology. July 7, 2011. Retrieved April 20, 2015: “ Many people argue that Android has put Linux into the hands of millions of users. While there is no doubting that Android has been a raging success, I would argue that Google has put Android into the hands of millions of people - not Linux. "
- ↑ a b Richard Stallman: Is Android really free software? - Google's smartphone code is often described as 'open' or 'free' - but when examined by the Free Software Foundation, it starts to look like something different ( English ) The Guardian . September 19, 2011. Retrieved September 9, 2012: “The software of Android versions 1 and 2 was mostly developed by Google; Google released it under the Apache 2.0 license, which is a lax free software license without copyleft. [...] The version of Linux included in Android is not entirely free software, since it contains non-free "binary blobs" [...] Android is very different from the GNU / Linux operating system because it contains very little of GNU. "
- ↑ Android Open Source Project. Retrieved June 29, 2020 .
- ↑ Richard Stallman: Android and User Freedom - Support the Campaign Free Your Android! . gnu.org. August 5, 2012. Retrieved September 9, 2012: "Although today's Android phones are considerably less bad than Apple or Windows smartphones, it cannot be said that they respect the freedom of users."
- ↑ What is Android? In: Android Developers Guide. Retrieved September 8, 2011 .
- ↑ zdnet.de: “How much Linux is in Google's OS?” By Christoph H. Hochstätter, May 18, 2011. Accessed September 11, 2013
- ↑ Anika Kehrer: How much Linux is there in Android? . Online at linux-magazin.de from November 10, 2009; Retrieved September 11, 2013.
- ^ Bill Anderson: Android is Just Another Distribution of Linux. Android News for Costa Rica, May 13, 2014, accessed on September 12, 2014 (English): “ Android is not a GNU / Linux distribution, but it is a distribution of Linux. More specifically, it is a distribution of embedded Linux that uses many NetBSD utilities. "
- ↑ Canonical brings Ubuntu to smartphones. (No longer available online.) Archived from the original on January 12, 2013 ; Retrieved January 18, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Jolla: First Sailfish smartphone at the end of 2013 for € 400. (No longer available online.) Chip.de, archived from the original on June 7, 2013 ; Retrieved May 29, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Key figures for the mobile market from Business Insider ( Memento of the original from May 27, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , April 15, 2012, Alexander Oschatz, Radenbul, accessed: June 19, 2012.
- ↑ Google's Android becomes the world's leading smart phone platform , accessed August 11, 2011
- ↑ Nokia's crisis deepens . NZZ -Online. August 11, 2011. Retrieved January 10, 2012.
- ↑ Market shares of Android and iOS in terms of sales in Germany. statista, accessed August 7, 2016 .
- ↑ Linux continues to grow in the embedded device market. pro-linux.de, March 25, 2015, accessed on August 7, 2016 .
- ↑ a b Tony Mobily: 2009: software installation in GNU / Linux is still broken - and a path to fixing it . www.freesoftwaremagazine.com. June 23, 2009. Archived from the original on June 26, 2009. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved August 4, 2011.
- ↑ Troy Hepfner: Linux Game Development Part 2 - Distributable Binaries ( English ) October 1, 2007. Archived from the original on October 13, 2007. Retrieved on December 19, 2011: “Creating an executable that works on almost all Linux distributions is a challenge . There are a number of factors that contribute to the problem [...] "
- ↑ John King: Upgrading packaged Ubuntu application unreasonably involves upgrading entire OS - Bug # 578045 ( English ) In: Launchpad . Ubuntu. May 10, 2010. Retrieved on May 27, 2012: "It is easier to upgrade to the newest stable versions of most applications - even open source applications - on a proprietary operating system than it is on Ubuntu."
- ^ Eskild Hustvedt: Playing well with distros ( English ) Linux Game Publishing . November 24, 2009. Archived from the original on September 21, 2011. Retrieved January 15, 2012.
- ↑ Miguel de Icaza : Linux and Independent Software Vendors ( English ) primates.ximian.com. November 4, 2003. Archived from the original on July 15, 2012. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved on April 7, 2012: "[...] staffing requirements for maintaining and testing [...] software for a dozen of distributions and release versions quickly becomes a big burden [...]"
- ↑ Dave Burke: Porting Osmos to Linux: A Post-Mortem (part 2/3) ( English ) hemispheregames.com. May 18, 2010. Retrieved June 16, 2012: “Didn't Love: Packaging the Game. It took days of effort to create the binary packages for Osmos […] How should an app be packaged in Linux? [...] There are no standards or clear answers to any of these questions. There's no documentation for this stuff! Asking on the forums will typically net you a spectrum of answers with no consensus answer and lots of little side arguments. I basically reverse engineered what I saw other apps doing (which sadly was of little comfort because everyone does it differently). I settled on supporting .deb / .rpm / .tar.gz with explicit 32 bit and 64 bit executables [...] "
- ^ The Register of UNIX Certified Products. Retrieved July 18, 2017 .
- ↑ Eric Brown: LSB 4.0 certifications aim to heal Linux fragmentation ( English ) linuxfordevices.com. December 8, 2010. Archived from the original on December 24, 2013. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved on November 16, 2011: “[…] LSB helps to reduce fragmentation, it does not eliminate it. "The issue of packaging and broader dependencies is still a big one (for me) at least" writes Kerner. "The same RPM that I get for Fedora won't work on Ubuntu, and Ubuntu DEB packages won't work on SUSE etc etc." [...] "
- ↑ openSUSE: Build Service cross distribution howto. Suse ( Novell ), May 11, 2013, accessed February 6, 2014 .
- ↑ Hisham Muhammad: The Unix tree rethought: an introduction to GoboLinux . www.kuro5hin.org. May 9, 2003. Retrieved June 3, 2010.
- ↑ Robert Staudinger: Distribution-independent packages with auto package - one for all . Linux magazine 2006/02. February 1, 2006. Accessed April 11, 2012: “Although they work on the same principle, RPMs from Suse 9.2 do not run under Suse 9.3, and certainly not under Red Hat. The Autopackage project relies on a uniform standard for the creation of installation packages. The individual packages resolve their dependencies themselves. "
- ↑ Thomas Leonard: Decentralized Installation Systems ( English ) osnews.com. January 16, 2007. Retrieved May 3, 2012.
- ↑ Simon Peter: AppImageKit Documentation 1.0 (PDF; 38 kB) PortableLinuxApps.org. Pp. 2-3. 2010. Archived from the original on November 29, 2010. Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved July 29, 2011: “Linux distributions mostly use package managers for everything. While this is perceived superior to Windows and the Mac by many Linux enthusiasts, it also creates a number of disadvantages: Centralization […], Duplication of effort […], Need to be online […], No recent apps on mature operating systems […], No way to use multiple versions in parallel […], Not easy to move an app from one machine to another […]. The AppImage format has been created with specific objectives in mind: Be distribution-agnostic […], Maintain binary compatibility […] "
- ↑ Bruce Byfield: Autopackage struggling to gain acceptance ( en ) linux.com. February 12, 2007. Archived from the original on March 31, 2008. Retrieved on January 21, 2012: "If Hearn is correct, the real lesson of Autopackage is not how to improve software installation, but the difficulty - perhaps the impossibility - of large -scale changes in Linux architecture this late in its history. It's a sobering, disappointing conclusion to a project that once seemed so promising. "
- ↑ Ricky Laishram: Software Center replaces Synaptic. June 23, 2011, accessed September 29, 2011 .
- ↑ Matthew Paul Thomas: UDS N Monday plenary: Getting great applications on Ubuntu ( English ) In: Ubuntu Developer Summit 2010 . October 25, 2010. Retrieved April 29, 2012.
- ↑ Ingo Molnár : Ingo Molnar ( English ) plus.google.com. March 17, 2012. Retrieved June 16, 2012: “So, to fix desktop Linux we need a radically different software distribution model: less of a cathedral, more of a bazaar. […] - totally flat package dependencies (i.e. a package update does not forcibly pull in other package updates) […] - a guaranteed ABI platform going forward (once a package is installed it will never break or require forced updates again). Users want to be free of update pressure from the rest of the system, if they choose to. "