Xephyr
Xephyr is a kdrive based X Server which targets a window on a host X Server as its framebuffer. Unlike Xnest it supports modern X extensions ( even if host server doesn't ) such as Composite, Damage, randr etc (no GLX support now). It uses SHM Images and shadow framebuffer updates to provide good performance. It also has a visual debugging mode for observing screen updates.
Possible uses include;
Xnest replacement - Window manager, Composite 'gadget', etc development tool.
Toolkit debugging - rendundant toolkit paints can be observered easily via the debugging mode.
X Server internals development - develop without the need for an extra machine / display.
Multiterminal with Xephyr - configuration is a single computer which supports multiple users at the same time
Screenshot
Lots of Xephyr's in action.
Download
Xephyr is available via git as part of the Xserver module.
More Infomation
See the README
Authors
Xephyr was written by Matthew Allum.
-- MatthewAllum - 10 Sep 2004