Tk::LockDisplay is a Perl/Tk widget that disables an X display until a proper authentication string is entered (typically the user's password). The authentication subroutine is specified during widget creation. People often lock their display for short periods of time when, for instance, they need to use the restroom. It's needed around here because folks use xlock which doesn't do AFS authentication, so they're "inconvenienced". While the display is locked, a simple "screen saver" is displayed in case someone needs to waste time. Tk::LockDisplay "wakes up" with a key press or mouse motion, and goes away when authentication is completed. After some number of (user configurable) seconds of inactivity, 10 by default, the password entry widget and logo are hidden so all that remains is the colorful screen saver display. The "velocity" of the moving screen saver pattern is also user configurable. Tk::LockDisplay ships with a few screensaver plugins, and has a hook to register your own Perl/Tk plugin or subroutine. The special plugin 'none' disables the screensaver animation. LockDisplay is currently crippled on Win32 systems - it pretends the login user name is $^O and the password is $^O (the operating system name). Eventually I'll make it work correctly on Windows NT. Oh, on Windows 95/98 the "lines" plugin has a memory leak, which I *think* is due to Tk not freeing memory when canvas lines items are deleted. I don't see this problem on NT or any flavor of Unix. Installation: perl Makefile.PL make make test make install Stephen.O.Lidie@Lehigh.EDU, 98/10/20