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Type | Display server |
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Website | x |
Xvfb or X virtual framebuffer is a display server implementing the X11 display server protocol. In contrast to other display servers, Xvfb performs all graphical operations in virtual memory without showing any screen output. From the point of view of the X client app, it acts exactly like any other X display server, serving requests and sending events and errors as appropriate. However, no output is shown. This virtual server does not require the computer it is running on to have any kind of graphics adapter, a screen or any input device. Only a network layer is necessary. Xvfb supports several X Protocol Extensions, such as Compositing and OpenGL GLX support via Mesa. [1]
Xvfb is primarily used for testing:
As an example, the following sequence of commands runs a virtual framebuffer X server as display :1, runs a program (xclock) on it, and captures the virtual screen in the file image.xwd using the xwd command:
Xvfb:1&xclock-display:1&xwd-display:1-silent-root-outimage.xwd
The result can be shown by running the xwud program (xwud -in image.xwd
).
The program xvfb-run is often used to automate the process of finding an available display and managing authentication:
xvfb-runcommand
Xvfb is also used for remote control. VNC over SSH can be faster than X11 over SSH, [4] specially reducing latency over the internet. [5] In this case, Xvfb is often combined with a lightweight window manager (such as Fluxbox or Openbox) and a VNC server such as X11vnc. A possible sequence of commands to start this on the server is:
exportDISPLAY=:1 Xvfb"$DISPLAY"-screen01024x768x24&fluxbox&x11vnc-display"$DISPLAY"-bg-nopw-listenlocalhost-xkb
The next step is to fire up a SSH client such as PuTTY with tunneling to localhost port 5900 enabled. A vncviewer can then connect to localhost to get remote control over the server.
ssh-N-T-L5900:localhost:5900user@remotehost&vncviewer-encodings'copyrect tight zrle hextile'localhost:5900
x11vnc's man page also contains instructions.
Xvnc (not to be confused with x11vnc) is very similar to Xvfb.
The X Window System is a windowing system for bitmap displays, common on Unix-like operating systems.
In computing, a windowing system is a software suite that manages separately different parts of display screens. It is a type of graphical user interface (GUI) which implements the WIMP paradigm for a user interface.
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Damn Small Linux (DSL) is a computer operating system for the x86 family of personal computers. It is free and open-source software under the terms of the GNU GPL and other free and open-source licenses. It was designed to run graphical user interface applications on older PC hardware, for example, machines with 486 and early Pentium microprocessors and very little random-access memory (RAM). DSL is a live CD with a size of 50 megabytes (MB). What originally began as an experiment to see how much software could fit in 50 MB eventually became a full Linux distribution. It can be installed on storage media with small capacities, like bootable business cards, USB flash drives, various memory cards, and Zip drives.
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chroot
is an operation on Unix and Unix-like operating systems that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name files outside the designated directory tree. The term "chroot" may refer to the chroot(2) system call or the chroot(8) wrapper program. The modified environment is called a chroot jail.
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This page is a comparison of notable remote desktop software available for various platforms.
A headless computer is a computer system or device that has been configured to operate without a monitor, keyboard, and mouse. A headless system is typically controlled over a network connection, although some headless system devices require a serial connection to be made over RS-232 for administration of the device. Headless operation of a server is typically employed to reduce operating costs.
-- I think you also won't get GLX if you don't have mesa-dri-drivers installed in the chroot. -- Thanks. That helped.