Mir is a computer
display server
In computing, a windowing system (or window system) is software that manages separately different parts of display screens. It is a type of graphical user interface (GUI) which implements the WIMP (windows, icons, menus, pointer) paradigm for ...
and, recently, a
Wayland compositor
Wayland is a communication protocol that specifies the communication between a display server and its clients, as well as a C library implementation of that protocol. A display server using the Wayland protocol is called a ''Wayland compositor' ...
for the
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
that is under development by
Canonical Ltd.
Canonical Ltd. is a UK-based privately held computer software company founded and funded by South African entrepreneur Mark Shuttleworth to market commercial support and related services for Ubuntu and related projects. Canonical employs staff ...
It was planned to replace the currently used
X Window System
The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems.
X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting wit ...
for
Ubuntu
Ubuntu ( ) is a Linux distribution based on Debian and composed mostly of free and open-source software. Ubuntu is officially released in three editions: ''Desktop'', ''Server'', and ''Core'' for Internet of things devices and robots. All the ...
;
however, the plan changed and
Mutter was adopted as part of
GNOME Shell
GNOME Shell is the graphical shell of the GNOME desktop environment starting with version 3, which was released on April 6, 2011. It provides basic functions like launching applications, switching between windows and is also a widget engine. ...
.
Mir was announced by Canonical on 4 March 2013
as part of the development of Unity 8, intended as the next generation for the
Unity user interface.
Four years later Unity 8 was dropped
although Mir's development continued for
Internet of Things
The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other comm ...
(IoT) applications.
Software architecture
Mir is built on
EGL and uses some of the infrastructure originally developed for Wayland such as
Mesa's EGL implementation
and
Jolla's libhybris.
The compatibility layer for X, XMir, is based on
XWayland
X.Org Server is the free and open-source implementation of the X Window System display server stewarded by the X.Org Foundation.
Implementations of the client-side X Window System protocol exist in the form of ''X11 libraries'', which serve a ...
.
Other parts of the infrastructure used by Mir originate from
Android. These parts include
Google's
Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...
Protocol Buffers
Protocol Buffers (Protobuf) is a free and open-source cross-platform data format used to serialize structured data. It is useful in developing programs to communicate with each other over a network or for storing data. The method involves an int ...
, and previously included Android's input stack, which has since been replaced by Wayland's libinput, prior to the end of 2015.
An implementation detail in
memory management
Memory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when ...
shared with Android is the use of server-allocated buffers which Canonical employee Christopher Halse Rogers claims to be a requirement for "the ARM world and Android graphics stack".
[
According to Ryan Paul of ]Ars Technica
''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, sci ...
,
it has basic Wayland support.
Adoption
, the only announced desktop environment
In computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphica ...
with native support for Mir was Canonical's '' Unity 8.'' No other Linux distribution
A Linux distribution (often abbreviated as distro) is an operating system made from a software collection that includes the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading one ...
announced plans to adopt Mir as default display server.
On 23 July 2013, Compiz
Compiz () is a compositing window manager for the X Window System, using 3D graphics hardware to create fast compositing desktop effects for window management. Effects, such as a minimization animation or a cube workspace, are implemented as lo ...
developer Sam Spilsbury had announced a proof-of-concept port of XBMC
Kodi (formerly XBMC) is a free and open-source media player software application developed by the XBMC Foundation, a non-profit technology consortium. Kodi is available for multiple operating systems and hardware platforms, with a software 10 ...
to Mir, based on the previous proof-of-concept port of XBMC to Wayland. On the same day Canonical developer Oliver Ries had confirmed that "this is the first native Mir client out in the wild".
Among Ubuntu derivatives using a non-Unity environment, Xubuntu
Xubuntu () is a Canonical Ltd.–recognized, community-maintained derivative of the Ubuntu operating system. The name ''Xubuntu'' is a portmanteau of ''Xfce'' and ''Ubuntu'', as it uses the Xfce desktop environment, instead of Ubuntu's Unity a ...
developers had announced in early August 2013 that they would evaluate running Xfce via XMir, but three weeks later decided to refrain from adopting it.
Ubuntu
In June 2013, Canonical's publicly announced milestones for Mir development were to ship Unity 7 with XMir by default and a pure X11 fallback mode with Ubuntu 13.10, remove the X11 fallback with Ubuntu 14.04 LTS, and Unity 8 running natively on Mir by Ubuntu 14.10. Later, on , Canonical announced a postponement of their Mir plans for desktop use and not use XMir as default in Ubuntu 13.10. Ubuntu Touch
Ubuntu Touch is a mobile version of the Ubuntu operating system, being developed by the UBports community. Its user interface is written in Qt, and is designed primarily for touchscreen mobile devices such as smartphones and tablet computers, ...
, however is targeted to ship with Mir and a smartphone version of Unity 8.
In May 2016, during his traditional video interview with the community held during the Ubuntu Online Summit, Mark Shuttleworth
Mark Richard Shuttleworth (born 18 September 1973) is a South African and British entrepreneur who is the founder and CEO of Canonical, the company behind the development of the Linux-based Ubuntu operating system. In 2002, Shuttleworth became ...
confirmed that "You will be able to get 16.10 with Unity 8, just like you can get 16.04 with MATE,or KDE, or GNOME. It'll be there, it'll be an option, and the team that's working on that is committed to making that a first-class option."
On 5 April 2017, Canonical announced that with the release of Ubuntu 18.04 LTS, the Unity 8 interface would be abandoned in favor of GNOME
A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...
. When asked if the decision would also mean the end of Mir development, Canonical's Michael Hall said that given the divergent development paths taken by Mir and its competitor, Wayland, "Using Mir simply isn't an option we have."
However, Mark Shuttleworth
Mark Richard Shuttleworth (born 18 September 1973) is a South African and British entrepreneur who is the founder and CEO of Canonical, the company behind the development of the Linux-based Ubuntu operating system. In 2002, Shuttleworth became ...
clarified on 8 April 2017 that development would continue for Mir's use in Internet of Things
The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other comm ...
(IoT) applications, stating: "we have lots of IoT projects using Mir as a compositor so that code continues to receive investment."
Toolkits
* SDL supported both Mir and Wayland starting with SDL 2.0.2 but it was disabled by default. Wayland and Mir support was enabled by default starting with SDL 2.0.4. With the release of 2.0.10, Mir support was dropped in favor of Wayland.
* GTK
GTK (formerly GIMP ToolKit and GTK+) is a free and open-source cross-platform widget toolkit for creating graphical user interfaces (GUIs). It is licensed under the terms of the GNU Lesser General Public License, allowing both free and propriet ...
3.16 included an experimental Mir backend, but was removed in GTK 4.
* Qt5
Qt (pronounced "cute") is cross-platform software for creating graphical user interfaces as well as cross-platform applications that run on various software and hardware platforms such as Linux, Windows, macOS, Android or embedded systems wit ...
is the official and supported toolkit for Unity8 and Ubuntu Touch, included in the Ubuntu SDK.
Controversy
In March 2013, Canonical Ltd. announced Mir as the replacement display server for the X.Org Server
X.Org Server is the free and open-source implementation of the X Window System display server stewarded by the X.Org Foundation.
Implementations of the client-side X Window System protocol exist in the form of ''X11 libraries'', which serve a ...
in Ubuntu. Previously, in 2010, it had announced that it would use Wayland. Canonical stated that it could not meet Ubuntu's needs with Wayland.[ There were several posts made in objection or clarification, by people leading other similar or affected projects.
When originally announcing Mir, Canonical made various claims about Wayland's input system, which the Wayland developers quickly rebutted.] Official Canonical documentation in 2014 states, "our evaluation of the protocol definition revealed that the Wayland protocol does not meet our requirements. First, we are aiming for a more extensible input event handling that takes future developments like 3D input devices (e.g. Leap Motion
Leap Motion, Inc. (formerly OcuSpec Inc.) was an American company that manufactured and marketed a computer hardware sensor device that supports hand and finger motions as input, analogous to a mouse, but requires no hand contact or touching. ...
) into account ... With respect to mobile use-cases, we think that the handling of input methods should be reflected in the display server protocol, too. As another example, we consider the shell integration parts of the protocol as privileged and we'd rather avoid having any sort of shell behavior defined in the client facing protocol." In late 2015 Mir switched from a custom Android-derived input stack to Wayland's libinput
Wayland is a communication protocol that specifies the communication between a display server and its clients, as well as a C library implementation of that protocol. A display server using the Wayland protocol is called a ''Wayland compositor' ...
.
Long-time Linux kernel
The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ope ...
developer Matthew Garrett
Matthew Garrett is an Irish technologist, programmer, and free software activist who is a major contributor to a series of free software projects including Linux, GNOME, Debian, Ubuntu, and Red Hat. He has received the Free Software Award ...
criticized the choice of licensing for Canonical's software projects, particularly Mir. Unlike X.Org Server
X.Org Server is the free and open-source implementation of the X Window System display server stewarded by the X.Org Foundation.
Implementations of the client-side X Window System protocol exist in the form of ''X11 libraries'', which serve a ...
and Wayland, both under the MIT License
The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license comp ...
, Mir is licensed under GPLv3
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general us ...
– "an odd hoice for "GPLv3-hostile markets" – but contributors are required to sign an agreement that "grants Canonical the right to relicense your contribution under their choice of license. This means that, despite not being the sole copyright holder, Canonical are free to relicense your code under a proprietary license." He concludes that this creates asymmetry where "you end up with a situation that looks awfully like Canonical wanting to squash competition by making it impossible for anyone else to sell modified versions of Canonical's software in the same market." Garrett's concerns were echoed by Bradley M. Kuhn
Bradley M. Kuhn (born 1973) is a free software activist from the United States.
Kuhn is currently Policy Fellow and Hacker-in-Residence of the Software Freedom Conservancy, having previously been executive director. Until 2010 he was the FLOSS C ...
, Executive Director of the Software Freedom Conservancy
Software Freedom Conservancy, Inc. is an organization that provides a non-profit home and infrastructure support for free and open source software projects. The organization was established in 2006, and as of June 2022, had over 40 member pro ...
.
Richard Stallman
Richard Matthew Stallman (; born March 16, 1953), also known by his initials, rms, is an American free software movement activist and programmer. He campaigns for software to be distributed in such a manner that its users have the freedom to ...
of the Free Software Foundation
The Free Software Foundation (FSF) is a 501(c)#501(c)(3), 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support the free software movement, with the organization's preference for software being distributed ...
has stated on the similar case of MySQL that he supports dual-licensing of GPL software, as long as there are no proprietary extensions or proprietary versions of the free program, which was not the case for MySQL.
In June 2013, Jonathan Riddell of Kubuntu
Kubuntu ( ) is an official flavor of the Ubuntu operating system that uses the KDE Plasma Desktop instead of the GNOME desktop environment. As part of the Ubuntu project, Kubuntu uses the same underlying systems. Kubuntu shares the same repositor ...
announced that Kubuntu did not plan to switch to Mir. He stated "A few months ago Canonical announced their new graphics system for Ubuntu, Mir. It's a shame the Linux desktop market hasn't taken off as we all hoped at the turn of the millennium and they feel the need to follow a more Apple or Android style of approach making an OS which works in isolation rather than as part of a community development method. Here at Kubuntu we still want to work as part of the community development, taking the fine software from KDE and other upstream projects and putting it on computers worldwide. So when Ubuntu desktop gets switched to Mir we won't be following. We'll be staying with X on the images for our 13.10 release now in development and the 14.04 LTS release next year. After that we hope to switch to Wayland which is what KDE and every other Linux distro hopes to do."
In September 2013, an Intel developer removed XMir support from their video driver and wrote "We do not condone or support Canonical in the course of action they have chosen, and will not carry XMir patches upstream."
See also
* List of display servers
References
{{Portal bar, Free and open-source software, Linux
Canonical (company)
Display servers
Free software programmed in C++
Ubuntu