Differences

This shows you the differences between two versions of the page.

--- other:x_conf [2022/08/05 08:06]
jypeter [What is an X server?]
+++ other:x_conf [2022/08/09 08:53]
jypeter [Using an X server on an Apple computer]
@@ Line 3: / Line 3: @@
 ===== What is an X server? =====
-An //X server// is not a server for distributing your perfect models output!
+  * An //X server// **is not** a server for distributing your perfect models output!
-An //X server// is basically a program running on your local computer that understands the [[https://en.wikipedia.org/wiki/X_Window_System_core_protocol|X Windows System protocol]] used by **remote Linux servers** to generate graphics, and that can //render// (i.e. display) the graphics generated remotely on your **local computer**.
+  * An //X server// **is** basically a program running on your **local** computer that understands the [[https://en.wikipedia.org/wiki/X_Window_System_core_protocol|X Windows System protocol]] used by **Linux computers** (**local** computer, or **remote** Linux servers) to generate graphics, and that can //render// (i.e. display) the graphics generated **remotely** on your **local** computer
+===== What do we mean exactly with Local and Remote computers? =====
+This page will very often mention **local computers** or **remote computers**:
+  * The **local computer** is the desktop or laptop you are interacting with (using a screen+mouse+keyboard)
+    * The local computer can be a **Linux, Windows or Mac (i.e //OS X//) computer**
+  * The **remote computer or server** is another computer that you also want to interact with (using the screen+mouse+keyboard of your local computer)
+    * We only consider on this page the case of a **remote //Linux// machine** that **requires a local running //X server//**
+  * **Remote Linux machine** can mean several things:
+    * It can be another operating system running inside **a [[https://en.wikipedia.org/wiki/Virtual_machine|Virtual Machine]] on your local computer**
+      * We mostly consider on this page the case of a **Linux virtual machine** using [[other:win10wsl|Windows Subsystem for Linux (WSL)]] on a Windows computer, but this can apply to other configurations
+    * It can be a **distant computer** or server in your building, or a high performance computer in a computing center on the other side of the Earth. It could also be a virtual machine in the //Cloud//
 ===== Using an X server on Linux =====
-Linux computers come pre-configured with a running X server (because they need it for displaying local graphics) that will display the graphics generated locally and on remote Linux servers. **You don't need to do anything special!**
+<WRAP center round tip 60%>
+You don't need to do anything special!
+</WRAP>
+Linux computers come pre-configured with a running //X server// that will display the graphics generated locally and on remote Linux servers
@@ Line 26: / Line 45: @@
 Type: <wrap em>free</wrap>
-Download the installer from [[https://sourceforge.net/projects/vcxsrv/|VcXrsv]] and install VcXsrv.
+Download the installer from [[https://sourceforge.net/projects/vcxsrv/|VcXrsv]] and install ''VcXsrv''.
 === VcXsrv Configuration ===
@@ Line 32: / Line 51: @@
 You need to configure ''VcXsrv'' to work in //multiple windows// mode. The following steps will show you how to create a shortcut on your desktop to start VcXsrv in this appropriate mode
-  * Start the configuration tool: ''Start'' => ''VcXsrv'' => ''Xlaunch''
+  * Start the //configuration tool//: ''Start'' => ''VcXsrv'' => ''Xlaunch''
   * Select ''Multiple windows'', then ''Next''
   * Select ''Start no client'', then ''Next''
-  * Keep the default ''Clipboard'' settings, uncheck ''Native opengl'' (not sure about that...), then ''Next''
+  * Keep the default ''Clipboard'' settings, uncheck ''Native opengl'', then ''Next''
+    * You can check the [[other:x_conf#opengl_related_settings|OpenGL discussion section]] if you have time...
   * Click on ''Save configuration'' and save an ''X_Server.xlaunch'' configuration file on your Desktop, then ''Terminate''.\\ You should now have a new ''X_Server'' icon/shortcut on your Desktop
   * Start the server by double-clicking on the new ''X_Server'' icon
-    * It will seem that nothing happens, but an ''X'' icon appears in the right side of the taskbar (you may have to look for it in the //Display hidden icons// pull-up menu). Your computer is now ready to display remote graphics!\\ {{ :other:vcxsrv_x.png?direct |}}
+    * It will seem that nothing happens, but an ''X'' icon will appear in the right side of the taskbar (you may have to look for it in the //Display hidden icons// pull-up menu). Your computer is now ready to display remote graphics!\\ {{ :other:vcxsrv_x.png?direct |}}
-    * The X server will stop when you close your Windows session or restart the computer. Do not forget to click on the X_Server icon if you know that you will need an X server later
+    * The X server will stop when you close your Windows session or restart the computer. Do not forget to click on the ''X_Server'' icon on your desktop if you know that you will need an X server later
+      * FIXME Document how to automatically start the X server...
     * Note: you can right-click on the ''X'' icon and select ''Exit...'' if you need to quit the X server
-  * You are now **ready**, if you only need VcXsrv to display graphical windows from remote servers
-  * The following steps allow you to test the X server in a **local** WSL+Ubuntu terminal. **Do not set the DISPLAY variable yourself when you are connected to a remote server with ''ssh''!**
-    * Open a **local** terminal (in WSL+Ubuntu)
-    * Type ''export DISPLAY=localhost:0.0''
-    * Type ''xterm'' and check that a new //xterm// terminal appears
 ==== Installing x410 ====
+<WRAP center round tip 60%>
+[[https://token2shell.com/x410/|x410]] is a **low cost** commercial //X server// that can be directly installed from the [[https://www.microsoft.com/store/productId/9NLP712ZMN9Q|Microsoft store]].
+This is an //X server//, and you will get the same functionalities as what is already provided for free by [[other:x_conf#installing_vcxsrv|VcXsrv]], **but**:
+  * Once installed, ''x410'' will be automatically updated by the Microsoft Store application
+  * If you move to another computer, you can install ''x410'' again by just [[other:win10config#connecting_to_the_microsoft_store|Connecting the MS Store to your account]] on the new computer. No need to buy it again
+  * There seem to be more (useful) updates than for ''VcXsrv''
+  * The interface is more modern, with more options, and there is a lot of useful information on the web site
+  * The ''x410'' name is easier to remember! :-D
+</WRAP>
 Type: <wrap em>commercial</wrap>
-[[https://token2shell.com/x410/|x410]] is a low cost commercial X server that can be directly installed from the [[https://www.microsoft.com/store/apps/9nlp712zmn9q|Microsoft store]]. Once installed, it will be automatically updated by the Microsoft Store application.
+Buy and install ''x410'' from the [[https://www.microsoft.com/store/productId/9NLP712ZMN9Q|Microsoft store]]
-**Starting, configuring and exiting X410**: you can start X410 by clicking on it in the Windows Start Menu, or choose to [[https://token2shell.com/howto/x410/automatically-start-x410-on-login/|Automatically Start X410 on Login]]
+=== x410 configuration ===
-  * Note: nothing actually happens when you start X410, as it is just waiting to display graphics! You will just get a new **X** icon in the //hidden// icons of the taskbar.
-  * You can configure (and exit) X410 by right clicking on its **X** icon
-==== Installing MobaXterm ====
+  * Start ''x410'': ''Start'' => ''X410''
+    * It will seem that nothing happens, but an ''X'' icon will appear in the right side of the taskbar (you may have to look for it in the //Display hidden icons// pull-up menu). Your computer is now __almost__ ready to display remote graphics!\\ {{ :other:x410_x.png?direct |}}
+  * Right-click on the ''X'' icon to open the **X410 settings**
+    * Select ''Auto copy to Windows after selection''\\ {{ :other:x410_settings.png?direct |}}
+  * It's possible to **automatically start ''x410''**! Otherwise, it will stop when you close your Windows session or restart the computer, and you will have to restart it by hand (''Start'' => ''X410'') if you know that you will need an X server later
+    * Open the **Windows Task Manager** (Right-click on ''Start'' and select ''Task Manager'')
+    * Go to the ''Startup'' panel (if there are no panels, select ''More details'')
+    * Right-click on ''X140'' and select ''Enabled''
+  * Note: if you need to quit the //X server//, you can right-click on the ''X'' icon, and then click on the //Display// number at the lower left (usually ''0'') and select ''Shut down''
-Type: <wrap em>commercial</wrap>
+===== Using an X server on a Mac =====
+===== Configuration on the remote Linux server =====
+==== If you are connecting with ssh or PuTTY ====
+Nothing special to do, if you are using [[other:ssh#using_an_x_server_to_display_graphics|"ssh -X" or "ssh -Y"]] or ''PuTTY'' to connect to a remote Linux server
+==== If you are using WSL ====
+You need to know what you consider as the //Local machine//, and what is the //Remote server//
+  * **Local machine**: your local **Windows computer**, where you have installed [[other:win10wsl|WSL+Ubuntu]]
+  * **Remote server** : we consider 2 types of remote servers:
+    * an **actual remote server**
+    * The **WSL computer** running on a **virtual machine inside your local Windows computer**. This can be considered as a different and //remote// computer, even it is running on the local computer\\ You need your local //X server// to display graphics generated in WSL
+    * **Define the ''DISPLAY'' variable** in the terminals used in WSL:
+      * //bash// shell: ''export DISPLAY=localhost:0.0''
+      * //tcsh// shell: ''setenv DISPLAY localhost:0.0''
+      * You probably want to define the ''DISPLAY'' variable automatically in one of the shell configuration files
+===== Testing =====
+The idea is to:
+  * Open a terminal and check that the ''DISPLAY'' environment variable is correctly defined on the local machine
+  * Connect to the remote machine
+  * Check that a (new) ''DISPLAY'' variable is automatically defined on the remote machine
+  * Check that you can start an application using graphics (e.g. ''xterm'') on the remote machine
+==== On a Linux computer ====
+Some basic commands in a terminal
+<code>[Local] $ hostname
+name_of_your_local_machine
+[Local] $ echo $DISPLAY
+:0
+[Local] $ ssh -X some_login@some_remote_server
+[some connection information skipped here]
+[Remote] $ hostname
+name_of_the_remote_server
+[Remote] $ echo $DISPLAY
+localhost:20.0
+[Remote] $ xterm</code>
+==== On a Windows computer with only an X server installed ====
+We just open a ''Powershell'' window (''Start'' => ''Windows Powershell'' => ''Windows Powershell'') and type some basic commands
+<code>PS C:\> $env:computername
+name_of_your_local_machine
+PS C:\> $env:DISPLAY
+PS C:\> $env:DISPLAY="localhost:0"
+PS C:\> $env:DISPLAY
+localhost:0
+PS C:\> ssh -Y some_login@some_remote_server
+Warning: No xauth data; using fake authentication data for X11 forwarding.
+[some connection information skipped here]
+[Remote] $ hostname
+name_of_the_remote_server
+[Remote] $ echo $DISPLAY
+localhost:19.0
+[Remote] $ xterm</code>
+==== On a Windows computer with PuTTY and an X server installed ====
+We assume here that [[other:putty_conf|PuTTY is already installed and configured]] and **correctly** configured (with ''Enable X11 forwarding'')
+We just have to open a pre-configured //PuTTY Session// on a remote server
+<code>[Remote] $ hostname
+name_of_the_remote_server
+[Remote] $ echo $DISPLAY
+localhost:19.0
+[Remote] $ xterm</code>
+==== On a Windows computer with WSL+Linux and an X server installed ====
+We assume that [[other:win10wsl|WSL+Ubuntu]] is installed and that the ''DISPLAY'' variable is [[other:x_conf#if_you_are_using_wsl|configured correctly]]
+Open a WSL terminal (you should know how, if you have installed WSL) and type some basic commands
+<code>[Local WSL] $ hostname
+name_of_your_local_machine
+[Local WSL] $ echo $DISPLAY
+localhost:0.0
+[Local WSL] $ xterm
+[Local WSL] $ ssh -X some_login@some_remote_server
+[some connection information skipped here]
+[Remote] $ echo $DISPLAY
+localhost:22.0
+[Remote] $ xterm</code>
+===== Troubleshooting =====
+==== Nothing works! ====
+That's unfortunate, but:
+  * Have you turned on your computer?
+  * Do you have network access, and an account on a remote server?
+  * Have you run the [[other:x_conf#testing|Tests]]?
+  * Have you installed and configured the //X server// correctly? Is it really running?
+  * Have you configured [[other:putty_conf|PuTTY]] and/or other required applications correctly ?
+  * Is the ''DISPLAY'' variable defined correctly on the local and remote computer?
+=== When DISPLAY is not defined correctly ===
+If the ''DISPLAY'' **variable is not defined (correctly)**, you will get a ''Can't open display: //[NO VALUE DISPLAYED HERE]//'' error
+<code>$ xterm &
+$ xterm: Xt error: Can't open display:
+xterm: DISPLAY is not set
+$ echo $DISPLAY
+</code>
+Make sure that you are using ''ssh -X'' or ''ssh -Y'', or that [[other:putty_conf#changing_some_useful_settings|PuTTY is configured]] with ''Enable X11 forwarding''
+=== When there is no X server running ===
+If the ''DISPLAY'' variable is defined, but there is **no X server**, you will get a ''Can't open display: localhost://[SOME VALUE]//'' error\\ <code>$ xterm &
+$ connect localhost port 6000: Connection refused
+xterm: Xt error: Can't open display: localhost:12.0</code>
+Time to [[other:x_conf|read this page again]]...
+==== OpenGL related settings ====
-Available at [[https://mobaxterm.mobatek.net/|MobaXterm]], not tested. This seems to be more than just an X server, and may be an overkill if you just need an X server
+It's hard to know what the best //OpenGL// settings for your //X server// are: it depends on your local computer, the remote computer, the network speed, the application generating the graphics, the libraries' versions...
-==== Troubleshooting ====
+  * If ''Native opengl'' is activated in ''VcXsrv'', you //may// have to also use the following environment variable on the remote computer: ''export LIBGL_ALWAYS_INDIRECT=1''
+    * or maybe not! You can try to understand the [[https://unix.stackexchange.com/questions/1437/what-does-libgl-always-indirect-1-actually-do|What does LIBGL_ALWAYS_INDIRECT=1 actually do?]] thread...
-  * Note: if you use ''VcXsrv'' and the content of some displayed //X windows// appear **blurry**, see if you can [[other:win10misc#vcxsrv_x_server|fix the compatibility settings]], or try to use **x410**.
+==== Blurry display ====
-===== Using an X server on an Apple computer =====
+  * If you use ''VcXsrv'' and the content of some displayed //X windows// appear **blurry**, see if you can [[other:win10misc#vcxsrv_x_server|fix the compatibility settings]], or try to use **x410**.

PMIP3 wiki

User Tools

Site Tools

Differences

Page Tools