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X servers

Relevance

This section is only relevant if you want to use an X server outside of the WSL environment, e.g., on a system where you only use CygWin as a Unix/Linux emulation layer and want to avoid the use of WSL.

Since late November 2022 the Microsoft store version of WSL is available. This is a version of WSL2 that contains built-in support for WSL (dubbed WSLg). Windows 11 will render the image in the Linux server and push the image to the Windows screen via the Remote Display Protocol, but also include features to support OpenGL acceleration on the graphics card if a compatible Windows display driver is used.

Also check the WSLg documentation on GitHub!

In the past, there were several commercial X servers that offered much better performance than the freely available ones. These however have lost popularity, especially when the server running the X applications is not on the same very fast network, as the limited network bandwidth and higher latency of longer network connections obliterate any speed advantage over the free alternatives (though some might still offer more functionality).

There are several X servers that are all derived from the X.org code base. Packaging those to run on Windows does require some effort from the developers of these packages, so some of the options below request a minor fee or donation to compensate for that effort.

  • Cygwin/X. Cygwin is a technology that offers a lot of Linux-functionality on top of Windows. This technology is discussed elsewhere. It also comes with an X server derived from the X.org code base. However, as one also needs to install the Cygwin system before being able to install the X server, it does require some more effort from the user than the other options given below. It is however entirely free.

  • MobaTek MobaXterm: This product was already discussed before. It's X-server is also based on the X.org sources and in fact relies on the built-in Cygwin. However, due to the integration in MobaXterm the interface is a bit more polished. The MobaXterm does support the GLX extension, but it is not clear if it is hardware accelerated or just a software OpenGL emulation. Recent versions integrate nicely with WSL also (tested with WSL2) and set the DISPLAY environment variable correctly so that you can start X programs in your WSL sessions started from MobaXterm. TODO: TEST ON A CLEAN MACHINE AS IT MAY PICK UP A VARIABLE SET BY GWSL.

  • GWSL: This free X server installs from the Microsoft Store which makes it extremely easy to install and gives you automatic updates. It is based on VcXsrv, the next one in this list, but installs from the Windows store. It has a feature to ensure that each WSL session starts with the display variable set properly and a simple tool to create shortcuts to WSL graphical apps to start them at the click of a button. GWSL does support the GLX 1.4 extension, but it is not clear if it is hardware accelerated or just a software OpenGL emulation. Like all X servers further down in the list, it is basically the work of a single person so there is no guarantee that the work will continue and limited support.

    A big disadvantage of this X server is that it runs with access control disabled, allowing all computers on the network to access the X server unless the firewall on your machine stops the applications from doing so. But tuning the firewall to only let traffic from the WSL virtual machine pass is no easy feat, also because the feature that sets the DISPLAY variable doesn't use the internal virtual connection. It may be a good enough X server to use at home but it should not be used in public spaces or on, e.g., a university network.

  • VcXsrv: This X server runs independently from the Cygwin libraries. It relies on an older version of the Microsoft compilers and some included libraries that make Cygwin unnecessary. It is installed through a regular Windows installer.

  • Xming X Server: This is another server that can run independently from Cygwin. While VcXsrv uses the Microsoft compilers, the author of Xming relies on a port of the GNU compiler collection (though of course you don't need to have those compilers installed). It consists of two components: the actual X server and a package with additional fonts. The server is donationware (a minimum of 10 GBP will give you access to new versions for a year), though an older version is available entirely free. The donationware version does support the GLX extension. For the free versions, there is a download with (the -mesa version) and without GLX, but the GLX support is very outdated (GLX 1.2) given that the free version is essentially the 2007 version of Xming. It is installed through a regular Windows installer. Xming works nicely with WSL1 as you can simply set the DISPLAY variable to localhost but is a bit more tricky to use with WSL2, which runs in a virtual machine and hence doesn't share localhost with Windows. You'll have to start Xming with access control disabled (using the -ac command line option) and set the DISPLAY environment variable in your WSL2 session with 

    export DISPLAY=$(cat /etc/resolv.conf | grep nameserver | awk '{print \$2; exit;}'):0

    which is a trick that works with the other X servers also.

  • X410: This is a port of the X.org X-server solely for Windows 10 and packaged as a Windows Store app, making it extremely easy to install and uninstall. It has a free time-limited test version but afterwards it costs around 10 or 15 EURO (well, the store claims it costs 49.99 EURO, but I've always seen the reduced price of 14.99 EURO and at one point even 9.99 EURO). It is also fully independent of the Cygwin libraries, which may make it an excellent partner to use with Windows Terminal which is also a Microsoft Store app.

Other free or nearly free X-servers:

  • MicroImages MI/X: Previously a commercial offering offered as part of their GIS software, but now made freely available. However, as this is based on a very old version of X we advise against its use. It is likely incompatible with many recent X packages.

In case you really want to go for a commercial offering, these are some of the options:

Many of the commercial offerings include the GLX extension for OpenGL software (or offer it for an additional fee) which is a feature not offered by all free servers, but it is not clear if their implementation is better than in the free servers that support the extension (e.g., by offering full hardware acceleration).

Note that we have no recent experience with any of these commercial products.