What is "xscreensaver"

XScreenSaver is a collection of about two hundred free screensavers for Unix, Mac OS X and iOS. It was created by Jamie Zawinski in 1992 and is still maintained by him.

The free software and open source Unix-like operating systems running the X Window System (such as Linux and FreeBSD) use XScreenSaver almost exclusively. On those systems, there are two parts to XScreenSaver: the collection of screen savers; and the framework for blanking and locking the screen.

In recent years, some Linux distributions have been using the gnome-screensaver or kscreensaver screen-blanking frameworks by default instead of the framework included with XScreenSaver. They still depend on the XScreenSaver collection of screen savers, which is over 90% of the package, with the exception of gnome-screensaver version 3 and onward, which has dropped support for screensavers completely, supporting only simple screen blanking.

On Macintosh systems, XScreenSaver works with the usual Apple screen saver framework, and X11 is unneeded.

In version 5.21 a time bomb has been introduced that displays large popups chastising the user for having an "outdated" version on login or interacting with XScreenSaver. The lock screen has similar wordage.

XScreenSaver is released under the terms of the X11 License.