Linux is, in a narrow sense, the Linux operating system kernel , and in the broad sense, any operating system that is based on the Linux kernel. This article covers the broad meaning.

Originally, the Linux kernel was developed for PC- compatible personal computers , and had to come with GNU software to build an operating system. Proponents of the GNU project have been promoting since the combined GNU / Linux name . Since the 2000s , the Linux kernel is used on computer hardware ranging from mobile phones to supercomputers , and is not always accompanied by GNU software. This is particularly the case of Android , which equips more than 80% of smartphones.

The Linux kernel was created in 1991 by Linus Torvalds . It’s free software . The Linux distributions have been, and remain, an important vehicle for popularizing the movement open source.

Project Philosophy: Hacker Spirit and Free Software

In his book The Daemon, the Gnu, and the Penguin , Peter Salus explains that this system was born from the encounter of the ” hacker  ” mode of operation  with the principles of the free softwaremovement , the hacker and free software philosophies are described as two facets of the same object.

Free software

The essential difference from GNU / Linux compared to other competing operating systems – such as Mac OS , Microsoft Windows and Solaris – is to be a free operating system , bringing four freedoms to users, defined by the License License General Public Library (GPL), making them independent of any publisher and encouraging mutual help and sharing.

Free software is not necessarily free, and vice versa free software is not necessarily free 8 . They are also not rights-free software: it is by virtue of their copyright that contributors of free software grant the four freedoms, which are to “use the software without restriction”, of “Study the software”, “modify it to suit its needs” and “redistribute it under certain precise conditions”, since their non-compliance could lead to convictions 9 .

Some licenses are based on the principle of copyleft , that is to say on the principle of reciprocity: a work derived from copyleft software must in turn be free. This is the case of the most used free license, including the Linux kernel itself: the GNU GPL license written by Richard Stallman .

The opening of the source code , one of the four criteria corresponding to the notion of free software , has benefits theorized among others by Eric Raymond , such as the quick bug fixes , including the correction of security vulnerabilities . It is the refusal of the principle of security by the darkness .

Interoperability

GNU / Linux could not have developed without the presence of standardized protocols used on the Internet . A good number of free software are besides implementations of reference, like Apache .

Proponents of free software are therefore constant advocates of interoperability . They highlight open formats , data formats whose technical specifications are public and without restriction of access or implementation, so as not to depend on a single software.

In this respect, Mozilla Firefox tries to respect scrupulously the recommendations issued by the World Wide Web Consortium , Jabber , which gave birth to the XMPP standard recognized by the Internet Engineering Task Force in the field of instant messaging or the suites LibreOffice and Calligra , who launched the OpenDocument standard in the field of office automation.

In other areas, there is no recognized standardization body or agreement. The market is then fragmented between various sellers who each have their technology or under the domination of a predominant economic actor who closes his formats or protocols.

The first case prevails in the instant messenger war and is partly solved by multiprotocol software like Pidgin or Kopete . The formats of successive Microsoft Office suites and the Server Message Blockprotocol that allows files and printers to be shared between different computers on a Microsoft Windows network fall into the second category (this is no longer true since the office suite uses XML files ). These formats and protocols are often not or poorly documented. Interoperability then necessarily passes through reverse engineering .

This may require significant work, work that is otherwise illegal in the United States but legal in Europe (as long as we remain within the framework of interoperability); today, OpenOffice.org can read the vast majority of files in different DOC formats, and Samba software can participate in Windows networks.

More problematic from the point of view of free software are the formats and protocols necessary for interoperability, but locked technically or legally: digital rights management , software patents , EUCD Directive , Digital Millennium Copyright Act , etc.

Unifix Linux 2.0 from the German company Unifix (and Linux-FT from Lasermoon) are also POSIX certified .1 FIPS 151-2 10 , 11 (Federal Information Processing Standard 12 ). Core 1.2.13 13 . [What?]

On the Debian site , it is explained that “the POSIX standards are not free and the POSIX.1 (and FIPS 151-2) certification is very expensive” 14 .

Communities

Many associations, known as the Linux User Group ( Linux Users Group in English ), seeking to promote GNU / Linux and by extension free software, through meetings where GNU / Linux demonstrations do, trainings, and for those who wish facilities on their computer.

Many communities exist on the Internet to help both beginners and professionals alike. Let’s mention the Linux-Linux site, the Linuxfr.org collaborative information site , which helps users to learn the basics of GNU / Linux thanks to a very active IRC network . And the Proselux  [ archive ] , Linux Sponsoring Group  [ archive ] or Linux-Godfather  [ archive ] projects allow the “linuxiens” to meet to help each other. Similarly, there are many sites grouping tutorialsas well as howto .

Distributions 

Free software is developed collaboratively, often independently of each other, and can be freely redistributed. It follows a particularity of the GNU / Linux world: the frequent separation between those who develop the software and those who distribute it.

A GNU / Linux distribution (or Linux distribution) is an end-user-ready solution that includes the GNU operating system , the Linux kernel , computer installation and administration programs, a mechanism making it easy to install and update software such as RPM or APT and a selection of software produced by other developers.

For example, a distribution might choose to specialize in the GNOME or KDE desktop environment . It is also responsible for the default configuration of the system (graphics, simplicity …), security monitoring (update installations) and more generally integration of the whole.

The diversity of distributions makes it possible to meet various needs, whether commercial or not; server-oriented, desktop or embedded; consumer oriented or knowledgeable public; general or specialized for a specific use (firewall, network router, computer cluster, etc.); certified on a given material; or simply completely free, that is, without any proprietary code.

Most distributions are derived from another distribution. Thus, as illustrated in the timeline of the GNU / Linux distributions, three distributions are at the origin of most of the others:

  • Slackware , appeared in 1993, which is today the oldest distribution still in activity, still maintained by Patrick Volkerding  ;
  • Debian , edited by a developer community;
  • Red Hat , edited by the American company of the same name which also participates in the development of Fedora

Many other more or less specialized distributions exist, being for the most part derived from the aforementioned projects. For example here are some specialized distributions “Desktop Environment”: Ubuntu , edited by Canonical Ltd. which is derived from Debian  ; MEPIS , also based on Debian  ; Zenwalk , derived from Slackware  ; OpenMandriva Lx and Mageia published by non-profit associations , derived from the late Mandriva Linux itself derived from Red Hat. There are also many Live CD releases , one of the most famous of which is Knoppix 15 , which offers the ability to boot into a full GNU / Linux operating system and access many software from the media. (CD, DVD or USB key) without prior installation on the hard disk, and without altering its contents. This versatility makes them very popular for demonstrations of GNU / Linux usage, and is even used as a system maintenance tool. Among the completely free GNU / Linux distributions recommended by the Free Software Foundation are Trisquel and gNewSense .

Finally, Linux From Scratch is a book that, from the source code of software, offers the reader to build his own GNU / Linux distribution .

Main Linux distributions 

Main article: List of Linux distributions .

Retaking the parent distributions of many other distributions in the timeline illustration:

  • Debian
    • Knoppix
    • Ubuntu
  • Slackware
    • openSUSE (originally SuSE)
  • Red Hat Linux
    • Red Hat Enterprise Linux
    • Fedora
  • Gentoo
  • Arch Linux

Dissemination of the system

OEM contracts and tax-free Windows

One of the challenges for GNU / Linux distributions is to partner with computer manufacturers to make it easier to find a computer sold with a pre-installed GNU / Linux-based system. Even though some distributions claim to have made the installation of a GNU / Linux-based system as simple as that of competing operating systems, the simple fact of having to be aware that other systems exist, of being willing to accept changes in your habits and having to install the system yourself is an undeniable disadvantage compared to the privileged situation enjoyed by Microsoft Windows and Mac OS X distributors . The Microsoft system is indeed omnipresent and Appleat the same time is the manufacturer of the Macintosh .

Otherwise, users of GNU / Linux may claim the refund of the share corresponding to the price of the operating system and software they do not intend to use, when buying a computer nine, as the law of some countries allows 16 . If Apple has been cooperative several times in the face of such demands, the repayment of Microsoft Windows is generally long and difficult although currently a series of court decisions has allowed some consumers to be reimbursed by manufacturers . Faced with the difficulty of obtaining this reimbursement based on the EULA , since 1998, the associations Linuxfrench and AFUL as well as Roberto Di Cosmohave launched an action for the tax refund Windows 17 .

This situation exists in Europe and North America , but not in some South American countries , where GNU / Linux distributions have more market share than Windows 18 .

This quasi-monopoly situation partly explains the weak distribution in Europe and North America of GNU / Linux among individuals. Another obstacle to the adoption of GNU / Linux is the incompatibilitywith the Windows binary programs (the development of Wine makes it possible to partially remedy this incompatibility). The weak similarity between GNU / Linux and Windows makes more necessary a certain adaptation. The Ubuntu (2004) and MandrakeLinux (1998) distributions, which became Mandriva Linux, are among the first to be oriented towards office use for the general public 19 , 20 .

 

Since , Microsoft contributes to the Linux kernel . Indeed, Microsoft has released several drivers for Linux, licensed GPLv2, to enhance the support of its proprietary virtualization system Hyper-V 21 , 22 .

Market shares

The concept of market share is a bit special in the case of the Linux kernel . Since the operating systems that use it are rarely “sold,” the financial measure is meaningless.

Only the number of machines using it regularly can be counted. If this is easy for supercomputers (few), it becomes more difficult for client computers (statistics based on the user-agent HTTP), and even more uncertain for embedded systems, except for music players, phones, and numerical tablets.

Market share on embedded systems

The Linux kernel equips most embedded systems, civil or military (box, robots, aerospace, drones …).

Android / Linux achieved a very high growth of 72% in mobile phones in 2010 23 .

Market share on supercomputers 

Linux is very much in the majority 24 .

  •  : 91.40% of TOP500 25
  •  : 93.80% of TOP500 25
  •  : 96.40% of TOP500 26
  •  : 97.00% of TOP500 (only one on Windows) 27
  •  : 99,60% of the TOP500 (498 Linux, 2 AIX )
  •  : 100% of TOP500 (500 Linux) 28

Market share on servers

In 2010, GNU / Linux accounted for 16.8% of the server market share for all uses , 29 according to a study by International Data Corporation (IDC), based on revenue generated.

Market Share on Web Servers 

Unix-like operating systems (hence also counting * BSD ) are largely in the majority, at 63.7% on30 :

  •  : 32.6% Linux 31

Indeed, UNIX type servers (and in this case, GNU / Linux) are very easily secure, and free for free, like GNU / Linux. However, when it comes to market share, it is difficult to count the use of free software.

Market share on network servers

Market share on customer accounts

In , a study of XiTi regularly performed on the systems used by visitors to 17,000 professional European websites gives 91.9% of market share to Windows (39.2% to Windows XP , 21.0% to Windows Vista , 18 , 3% to Windows 7 , 16.3% to Windows 8 and 4.2% to Windows 10 ), 5.3% to Mac OS X and 0.9% to GNU / Linux 32 .

Statistics published by StatCounter and netmarketshare on the share of GNU / Linux in the world:

Year StatCounter 33 Netmarketshare
2007 0.67% 34
2008 0.69% 0.83% 35
2009 0.69% 1.01% 36
2010 0.78% 1.00% 37
2011 0.79% 1.06% 38
2012 0.84% 1.16% 39
2013 1.16% 1.38% 40
2014 1.43% 1.55% 41
2015 1.67% 1.57% 42
2016 43 2.31% 44

The consumer- related sale of many computers pre-installed with Windows partly explains the small market share of GNU / Linux on the client computers, although this tends to increase.

Technical characteristics

Interfaces

The command line

By filiation with UNIX , the command line (or Unix shell ) is always available in GNU / Linux, regardless of the distribution.

It has remained a long time unavoidable, but it is no longer true with recent distributions and simple to use dedicated to personal use, such as Ubuntu or Kubuntu . Nevertheless, online helpers often mention the command line approach, even when a graphical configuration is possible: this method is more universal in the GNU / Linux world, and often easier to explain for the person helping, and his interlocutor only has to copy-paste the indication.

A well-designed graphical interface nowadays makes it possible to perform the vast majority of tasks much more pleasantly, but this is not always the case, especially when the task has a repetitive or unforeseen aspect. The command line, which draws its power from its ability to infinitely combine automatic subtasks, and which almost automatically allows to automate the task thus accomplished, can then be more efficient than the graphical interface. Scientists, engineers and developers are among its most frequent users.

Graphical interface and command line can also complement each other: KDE and GNOME come with a terminal to drive, and therefore, automate all graphics applications from the command line.

Apple , well known for its graphical interfaces – MacOS being the first system marketed with windows and mouse management – has also integrated a UNIX-compatible command line terminal on Mac OS X.

Some distributions, especially those specialized in servers or certain administrative tasks, use only the command line, especially for its low resource consumption, due to the absence of graphical interface , but especially for its power of action , related to the interoperability of commands and the ability to generate scripts .

Applications

User-friendly distributions for the general public such as Ubuntu and its derivatives using deb packages , Mageia using rpm packages , and so on. enjoy many free, free, ergonomic and graphical programs. They make it possible to carry out the great majority of the tasks carried out daily: office automation, visualization of photos, image processing, reading of musics, visualization and edition of videos, web browsers, messaging and voices on IP (skype, XMPP , etc.). ). Some programs also allow professional use: programming, accounting, 3D drawing, CAD, FTP, etc.

Many programs can be used from a single terminal. We can mention the Vim , Emacs and sed editors , or the apt and rpm package managers . Some of these programs can also be used through a graphical interface.

There are many reasons for the multitude of programs running in console mode:

  • historical reason: originally, GNU / Linux lacked a graphical environment  ;
  • efficiency: programs that do not use the graphical environment require fewer resources;
  • speed: opening a console to type a command is often much shorter than going through the various menus of a window manager or a graphical environment;
  • concern for better control;
  • possibility to easily integrate them into more complex programs via scripts or in scheduled executions (batch)

Using these programs can be difficult for someone who is not used to working in text mode. They are, however, very popular with experienced administrators and developers, and become a must for high demands in these areas.

X Window Managers

The use of the generic term GNU / Linux is misleading when it comes to using a personal computer. Indeed, there are several interfaces (or window manager ) with different characteristics, like KDE , GNOME or Xfce .

However, because all these interfaces are X Window-based , their applications can coexist and offer common features including remote window display (including compressed and encrypted protocols like ssh and nox) and simplified copy and paste. : a text selected by the mouse is automatically copied, a middle click (or a click, or both buttons at the same time) is enough to paste the text to the desired location. So there is never need for the keyboard to copy and paste under X.

 

Traditionally, the interface of a Linux kernel- based operating system was a simple or spartan interface, centered around a window manager (there are many such as Window Maker or IceWM ) and a fairly heterogeneous applications.

The disadvantage of this traditional system is the time required to customize such an environment, and especially the non-standardization of the applications thus used. The applications that can be seen on the right screenshot ( XMMS , RealPlayer , Mozilla Firefox , xterm , Gaim , Konqueror ) each follow their own conventions: appearance, behaviors, different keyboard shortcuts; copy and paste and drag and drop are disparate …

While apps such as Vim or Emacs may have brilliant features, the disparate set of applications makes it a difficult system for novice users. The time spent learning an application and the reflexes thus acquired can not be applied to other applications, an advantage brought by the standardization of behavior of interfaces as shown by the Macintosh , with for example the keyboard shortcut used to quit an application. : Ctrl +  Qor Ctrl +  X –  Ctrl +  Cor Ctrl +  Cor just qor Escor again : qa! byequit or exit , etc.

Using this type of environment may seem confusing to users accustomed to other solutions (such as KDE or Gnome). It has the advantage of simplicity and flexibility of configuration and customization according to the needs of each.

Office environments

The condition of the previous chapter of places described in a manifesto 45 from 1996 grown Matthias Ettrich to base the project in response KDE and Miguel de Icaza to found the project GNOME the following year, inspired by Mac OS and Windows in terms of software ergonomics and behavioral standardization.

These two projects became the federators of GNU / Linux on the workstation.

Each one offers:

  • programmers, a very productive programming environment as well as recommendations for interfaces (in English: guidelines ) making it possible to produce faster applications that are easier to use;
  • translators, an infrastructure. These two environments and their myriad software are translated into dozens of languages 46  ;
  • artists, workspaces 47 to exercise their talents;
  • ergonomics specialists, the possibility of making it simpler and more consistent 48  ;
  • external applications, a reference environment in which to integrate 49  ;
  • and therefore, the user, a complete, integrated and consistent environment and a suite of essential applications: file explorer , web browser , media player , email client , address book, PDF reader , manager images.

These two desktop environments have recently reached a certain maturity, let us mention the year 2003 for KDE 50 , a little later for GNOME. Both projects are very active, but intend to improve significantly for their next major releases; efforts in this direction are concentrated in Appeal projects for KDE, and ToPaZ 51 for GNOME.

Technically, they are both based on many common technologies, first and foremost the X11 windowing system . To avoid duplicating some efforts, an informal area of ​​collaboration between these projects named Freedesktop.org has been set up.

It is in the approach of the ergonomics (this one being related to the type of user) and in the conception of the role of an office environment that they differ: the environment KDE pushes far the will of integration between applications, has many advanced features and plays the card configuration while making sure to have good choices by default; GNOME is more refined and dedicated to the essential tasks (taking the philosophy of making things just work ). Everyone, therefore, likes a different audience.

We can also note the rise in power ref.  desired] a third desktop environment called Xfce , which aims to provide a full GNOME- based GTK + environment, while remaining lighter than the latter or KDE.

Software offer

Related article: List of popular software on GNU / Linux .

The free software community has produced a lot of software that can be used in many areas. Here are examples of softwares given as an indication:

  • office automation with LibreOffice or Calligra ;
  • Internet with Mozilla Firefox , Chromium , Konqueror , Epiphany , Mozilla Thunderbird , Pidgin , or Transmission  ;
  • multimedia with Xine , MPlayer , VLC media player , XMMS , Totem or Amarok  ;
  • graphics, with GIMP , Inkscape or Scribus  ;
  • 3D with Blender .

Most GNU / Linux distributions offer a program (like Synaptic ) to navigate through a list of tested and preconfigured software specifically for a distribution. These programs are then downloaded and installed in a few clicks, with an electronic signature system to verify the authenticity and integrity of the software offered. These programs are then updated automatically.

Some important proprietary software also has a GNU / Linux version. This is the case of Opera , Adobe Flash Player , Adobe Acrobat Reader , NeroLinux or Skype for example.

The notion of portability refers to the ability of a program to be used under different operating systems or architectures.

Finally, it is possible to use software made for Microsoft Windows on a GNU / Linux station thanks to an implementation of the Windows API under GNU / Linux like Wine . Wine-based commercial offerings like CrossOver make it possible to use software such as Microsoft Office and Photoshop from the Windows world with almost no problems .

Video Games

There are many 52 games available under GNU / Linux, free or paid, free or proprietary. The offer includes both small office games (cards, minesweeper, chess, golf) and recent commercial games ( Enemy Territory: Quake Wars ).

Some games are designed to run natively under GNU / Linux ( Quake III Arena or 0 AD for example), and others can be run using programs that implement the Windows API under GNU / Linux. There are several implementations , some of them especially for games, allowing many Windows-based games to run in environments like Cedega and Wine.(eg World of Warcraft) but the major video game publishers do not distribute any of their video games in a 100% compatible version that supports GNU / Linux. The last resort for players using GNU / Linux is simply to use Windows on the same computer at the same time thanks to multiboot or virtualization .

The graphics card manufacturer ATI has for a while developed its own drivers for GNU / Linux. Following its acquisition by AMD , ATI opened the specifications of its cards in early 2008 so that the developers of Mesa 3D can better integrate the management of its cards.

In 2013, the Steam platform of Valve is available on GNU / Linux, it allows the game library to expand many titles including Team Fortress 2 , Half-Life , etc or the entire Valve library , likewise Amnesia: The Dark Descent or FTL: Faster Than Light 53 . In parallel, Gabe Newell announces the Steam Machine , a home console that will be offered with SteamOS , an operating system based on the GNU / Linux Debian 54 distribution .

Free Libraries

Software that uses a free library can run on GNU / Linux and on all platforms where the library is located. These libraries can add a graphic overlay on existing textual applications as is the case with Vim , but they are mainly used to develop software accessible to novices and with the features allowed by GUIs, such as drag and drop, mouse manipulations, etc.

Other applications like Blender or Google Earth are a special case because they use the OpenGL library for the basic implementation and management of programs using 3D as 2D.

Emulation 

Several emulation software exists to simulate the operation of competing operating systems or gaming environments.

Computer Emulation

The Steem and ARAnyM programs emulate much of the written applications for Atari machines , including Atari ST and Atari TT . UAE (Unix Amiga Emulator) can emulate the Commodore Amiga , Basilik the old Mac 68000 Apple. All these emulators emulate the microprocessors of the 68000 family of Motorola that equipped these computers, as well as the specialized coprocessors of the Amiga.

MESS (often associated with MAME) can emulate in the same way a large number of 8-bit personal computers . There are also specialized emulators for each of these computers: Euphoric for Oric , FMSX for MSX , but also emulators of ZX Spectrum , Commodore 64 , etc.

Application Usage for Microsoft Windows

Applications developed for Windows can run on a GNU / Linux system via the application Wine (or its derivatives trading CrossOver and Cedega ) that reimplements 55 the functioning of key API of Microsoft Windows . The microprocessor is not emulated, only the functions of APS are remapped on the fly on the APIs used natively in GNU / Linux. For example: DirectX uses OpenGL, the print management is relayed to CUPS or LPR, USB devices libusb  (en), graphic tablets to XInput, etc. This allows in many cases performance close to native execution, while avoiding the problems of some device drivers inherent in Windows. In some specific cases, the performance of some applications may be degraded. Many utilities, applications of all domains and games run perfectly, but not all. Wine’s website references working and problematic applications.

Virtualization

In addition, GNU / Linux also opens the possibility of a perfect separation between multiple virtual environments running on a single physical computer, taking into account the virtualization modules present in recent processors such as AMD-V on AMD and Intel-VT (or IVT) on Intel. These virtualization environments make it possible to run different environments or several similar environments on the same machine, while providing some security in the separation of accesses. This system has been used for a long time by IBM mainframes. IBM has also ported GNU / Linux on them to allow its customers to continue using them with a more modern system.

KVM is, since version 2.6.20 of the Linux kernel, the official hypervisor virtualization system of the latter. Coupled with the tools of QEMU , it allows to create virtual computers running directly on an unmodified Linux kernel and is able to host a large number of operating systems such as Windows , Solaris , BSD , etc. KVM is at the heart of Red Hat’s virtualization strategy .

Thanks to its openness, the Linux kernel also allows, with more or less significant modifications, the use of other virtualization products such as:

  • Oracle VM VirtualBox , developed by Sun under the name of Virtualbox, before the company was acquired by Oracle Corporation , which stands out above all by a very user-friendly interface for managing virtual machines in a graphical environment. Virtualbox is available as a free version and as a paid version, the latter offering additional features;
  • Qemu , free virtual machine
  • Xen , a server-based paravirtualization system that can offer very high performance without resorting to hardware emulation, but requires guest operating systems to be modified to achieve this level of performance. Xen is free but requires major changes to the Linux kernel;
  • VMware , a professional virtualization system, not free, available in server and workstation versions;
  • Docker
  • OpenVZ ;
  • Bochs .

Hardware support

Consumer distributions support the vast majority of hardware built into personal computers and home accessories (hard drives, webcams, mice, printers, video projectors, DVD players, graphics and audio cards, bluetooth, etc.).

Support for hardware equipment is one of the main criticisms of GNU / Linux. Indeed, some special equipment is not directly supported by GNU / Linux and there is not always a driver developed by the manufacturer and compatible with GNU / Linux. Some manufacturers routinely provide drivers for Microsoft Windows and Mac OS X , while for GNU / Linux, it is often the community that develops them by reverse engineering . Sometimes, the community prefers to develop stable free drivers although proprietary drivers developed by the manufacturers exist (this is the case for ATI or Nvidia graphics cards).). With this in mind, the drivers needed to fully operate a computer are integrated with most GNU / Linux distributions.

Some devices may not have available drivers. However, Windows or Mac OS users may also experience driver issues when they install a new version of their system, and the lack of source code prevents a recompilation of the proprietary drivers. Finally, sometimes there are only drivers for GNU / Linux, and not for Windows or Mac (supercomputers, high-end Internet servers, PlayStation game consoles, old devices whose support has been stopped by manufacturers , etc.). Old hardware can usually be recycled under GNU / Linux, because the durability of free drivers is also one of the strengths of GNU / Linux.

The first reason for this situation is the low impact of GNU / Linux on individuals, which does not encourage manufacturers to invest in developing drivers for this environment. The second reason is the refusal of certain distributions ( Fedora or Debian [ref. Required] 56 , for example) to take on drivers under proprietary licenses, even when they exist, forcing the user to find and install them manually. Finally, the absence of a fixed API in the Linux kernel forces manufacturers to issue driver binaries adapted to each version of the kernel [ref. necessary] .

Users who work on multiple platforms and need these drivers may find third-party-developed versions, but such drivers typically only support a rudimentary set of features, and only appear after the release. hardware, with some latency. However, there are mechanisms to run some drivers developed for other operating systems (such as NdisWrapper ).

The webcams are, for example, particularly concerned by this lack of drivers, but the USB video device class or UVC protocol makes it possible to answer this problem with many webcams supporting this protocol 57 .

With the democratization of GNU / Linux, some major manufacturers are making efforts to develop or provide the information needed to develop free drivers for GNU / Linux, such as Creative Labs for its webcams or sound cards 58 , Intel (processors, 3D chipsets, cards network, etc.). But many other components need to check the availability of drivers before the purchase, if they are intended for use under GNU / Linux. On the other hand, assemblers, such as Dell 59 , Asus – pushed by Intel and its project Moblin 60 – Lineo  (in) or Everex , sell computers with GNU / Linux preinstalled.

Linux and security

Linux allows a strict separation of privileges . One of the consequences is that, except for a security breach allowing privilege elevation 61 , a worm or a computer virus can only access a portion of the resources and functionalities of a Linux system, but neither to the important data of the system nor to the data of any other users 62 .

In the area of ​​servers, the degree of security depends, in comparison, primarily on the degree of experience that the systems administrator has . There, Linux scores points thanks to its freedom of use, which allows without risk and without additional cost to extensively test various scenarios on other computers, and to acquire a useful experience.

There is a series of specifically security-focused distributions , and initiatives such as SELinux from the National Security Agency . But there is also a series of distributions focused on anti-security, such as Damn Vulnerable Linux , BackTrack or more recently Kali Linux to educate experts on security issues on this operating system.

Linux supports a wide variety of hardware platforms, as well as software solutions. A security breach affecting the most popular email client will only affect a fraction of free software users; on the other hand, a flaw in Outlook Express could hit a huge proportion of Windows users at once. This thesis is developed in a report written by experts in the field, such as Bruce Schneier on behalf of the CIA and taken over by Gartner in a document 63 . This report states that since most computers run on a Microsoft operating system, most of the world’s computers are vulnerable to the same viruses and worms at the same time. It proposes to avoid this to avoid software monoculture in the field of operating systems.

Finally, the fact that Linux and many software running Linux are free software allows its source code to be studied critically by anyone wishing to do so, whether to make adaptations, in an educational setting, to meet to the private interests of a company or an institution or by mere personal interest (to seek vulnerabilities for example, most of the time unveiled and corrected extremely quickly). In connection with this, one often hears the argument that security breaches are corrected more quickly, assertion approved and refuted by various studies, usually depending on their source of funding. Finally, the freedom of software renders useless the use of software piracy,cracks or other warez sites that are very popular among other operating system users, and which is a vector of computer infection.

Still, Linux is not totally insensitive to security problems, as shown by the Slapper worm in September 2002, the first of its kind to reach a significant number of Linux computers, primarily Apache-basedweb servers (six thousand at the apogee of the worm 64 ). The Shellshock flaw on the Bash shell, by default on many Linux distributions is another flaw (affecting the passage Mac OS ) that has just been discovered. It was already old: it would be twenty years old. She would not have been discovered before.

In addition, Linux remains a vulnerable operating system 65 [ref. insufficient] , and nearly four thousand nine hundred vulnerabilities were identified between 2003 and 2008, they are spread over the various distributions available 66 . Most of them were corrected fairly quickly.

On the other hand, the number of faults discovered during a specific period is not a reliable measure to determine the security of an operating system, it is necessary to determine:

  • their impact on the system;
  • and the vulnerability time of the system 67 .

However, an article published in particular on Génération NT on June 26, 2013 indicated that Android was concentrating 92% of all the threats due to mobile malware contradicting in practice the optimism that has long prevailed in the Linux community [ref. necessary] 68 , 69 . This appreciation is moderated by the fact that Linux is only the heart of Android, nothing guarantees the security of Android applications of various origins.

Digital Rights Management

The DRM ( Digital Rights Management – DRM English – DRM is often called “digital restrictions management” English Digital Restrictions Management by the Free Software Foundation and free software activists 70 ) relates to the field multimedia, including music and videos that can be purchased over the Internet. Some works are protected by digital locks , aimed at controlling the use of the work, for example by limiting the number of plays or possible copies. These DRMsrequire the use of a particular technology, which is the exclusive property of the manufacturer and seller of said DRM , which explains that the reading of a protected work is linked to the use of a specific program. The Two Largest Manufacturers of Digital Rights Management Systems, Microsoft and Apple , Condition the Use of Works Protected by Their Systems for Use by Windows Media Player and iTunes, respectively. Since these companies sell their own operating system, they do not want to offer any version of their GNU / Linux programs. Thus, it is often not possible for GNU / Linux users to buy music online on a paid download site, or to listen to music already purchased and downloaded.

There are also DRMs on audio CDs, but these are much less standardized and less common. Most are designed to work with Microsoft operating systems and are therefore likely to be inoperative for a GNU / Linux user.

It is not a matter of technical limitations, since free management systems exist 71 . See also Linus Torvalds , according to which GNU / Linux and rights management are not incompatible 72 .

Uses

Server

Due to GNU / Linux’s relationship with UNIX , GNU / Linux quickly became a fixture in the IT server market. A crucial point was the ability to use a UNIX-like operating system on PC-compatible hardware , much cheaper than proprietary UNIX-based solutions and specific hardware. Many popular and widely used server software ( HTTP server , database , groupware , e-mail server , etc.) are available for free, generally without any limitation, and reliable, the market share of GNU / Linux in this domain grew accordingly rapidly.

GNU / Linux with a reputation for stability and efficiency in maintenance ref.  desired] , it meets the requirements of any server operating system. In addition, the modularity of a system based on the Linux kernel allows the exploitation of servers dedicated to a particular task. The Linux kernel port on many hardware components means that GNU / Linux is now usable on all the architectures used in this domain. The usable material is therefore considerable. The latest IBM eServer p5 and IBM eServer i5 are for example supported by IBM with a GNU / Linux operating system and allow to run multiple GNU / Linux systems in parallel.

GNU / Linux servers are run in just about every domain. One of the best-known examples is summarized by the acronym LAMP , where GNU / Linux propels an Apacheweb server associated with the MySQL database and the PHP programming language (alternatively: Perl or Python ). GNU / Linux is also often used as a file server, most often in Windows networks thanks to the Samba server , less often under NFS or AppleShare .

Network Security

Linux, which has a good reputation for security and performance (scalability) is widely used in the field of computer networks, such as gateway , router , proxy or firewall .

Central computer 

The free aspect of the source code, and the consequent possibility of adapting the system to a specific task, has allowed GNU / Linux to enter the data centers. In this market of mainframes , large reliable computers optimized for massive data processing, ubiquitous in banks, insurance companies and large corporations, GNU / Linux is increasingly competing with proprietary UNIX systems that were once Standard.

Clusters of servers 

GNU / Linux was used early in the field of server clusters (in English: clusters ), for example by the search engine Google in the late 1990s 73 . In this configuration, associated with the notion of grid computing , simple computers running a specialized GNU / Linux distribution work independently within a large network of computers.

Supercomputers

The supercomputers are designed to achieve the highest possible performance with the known technology, particularly in terms of computing speed. In November 2006, according to TOP500 , GNU / Linux turned 74% more powerful five hundred computers in the world 74 (against 20% for UNIX), the most powerful, both servers BlueGene of IBM (40 960 and 131 072 processors ). In November 2007, in this same TOP500, more than 85% of supercomputers use GNU / Linux, against 6% for UNIX and 1.20% for Windows. In November 2008, 87.8% of supercomputers run on GNU / Linux against 4.60% on UNIX 75. In November 2009, 446 supercomputers (89.20%) use GNU / Linux and only 5 are on Windows (1%) 76 .

The Titan , manufactured by Cray Inc. , is the most powerful supercomputer to date (November 2012); it works with a version of GNU / Linux called Cray Linux Environment 77 . The IBM Roadrunner , which was the first to officially exceed the symbolic power of 1 petaFLOPS , runs under the Fedora 78 Linux distribution .

Embedded

Extended GUI and OpenZaurus software based on Linux.

Linux is also at the heart of many consumer computing and electronic devices, and sometimes without the user’s knowledge. These include network equipment and small digital devices for mass consumption, usually equipped with a specialized energy-efficient processor and flash memory .

The success of Linux in this field is, here as elsewhere, that manufacturers appreciate the ability to adapt the software to their needs (consumption, interface, additional functions, etc.) and to benefit from the experience and work of an active community. Linux is also appreciated in this area for its reliability, its resistance to attacks from hackers on networks and of course its free. Embedded, Linux is frequently used with the tools uClibc and BusyBox that have been developed for hardware particularly limited in memory capacity.

Specialized cooperation forums help manufacturers of these products by making available instructions, programs and code examples, and striving to standardize Linux programming interfaces in the embedded. The OSDL launched thethe Mobile Linux Initiative to accelerate the progress of Linux in this area.

Networks and communication
Linux runs several routers including some Linksys models , as well as various terminals provided by ISPs (such as Freebox , SFR Neufbox or Livebox in France).
Phones and PDAs
Linux is also found on a range of mobile phones ( Linux phones  : Motorola ), Sharp Zaurus personal assistant and Nokia 770 , Nokia N800 and Nokia N810 internet tablets . In the field of personal navigation assistants , TomTom’s stand-alone GPS systems are designed from a Linux platform. The operating systems for Androidmobile , webOS (released by Palm before its purchase by HP ), Tizen (formerly MeeGo) but also Maemo , used on the Nokia N900 , all have a Linux kernel .
Multimedia
Linux is used in standalone players DivX , many Media Center , televisions and DTT decoders on demos ” th generation” as the Dreambox and Vu +, on audio players like those of SanDisk and the multimedia players of ‘ Archos .
Game console
The GP2X GamePark, video game consoles, mobile
The Pandora (portable console) , open source gaming console that has a compiled Linux operating system for ARM processors
The PlayStation 3 from Sony could use Linux but a so-called security update has removed this possibility
robotics
The market taking off from fun robot systems uses a Linux OS ref.  desired] .

 

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