Screen Locking	SLAC Computing UNIX at SLAC
	Updated: 14 Mar 2008

Lock your screen!

Whenever you get up and walk away from your computer without logging off, you should make sure your system is locked, i.e., requires you to type your password to resume your session. It is also highly desirable to obscure the contents of your screen, in case you have a window open displaying some data that should not be public. These functions are usually combined in a screensaver. Screensavers usually can be set to lock your computer automatically after some period of inactivity. This is a useful fallback in case you occasionally forget to activate the screensaver manually. However you should not just rely on the automatic timeout — get in the habit of activating the screensaver manually every time you walk away.

Here are instructions for configuring and activating the screensavers in the most popular UNIX desktop environments at SLAC.

• Gnome (Linux)
• KDE (Linux)
• CDE (Solaris)

Gnome

Activate Screensaver

To activate the screensaver, open the Actions menu (normally at the top of the screen) or the main menu (the red hat or footprint icon, normally at the bottom of the screen) and select Lock screen.

Create a Padlock Icon

You can create a padlock icon on one of the panels at the top or bottom of the screen so that you can activate the screensaver with a single click. To do so, click on the Actions menu or main menu and drag the Lock screen entry to the desired location.

Create a Lock Shortcut

You can also create a keyboard shortcut to activate the screensaver:

• Open the Actions menu or the main menu and select Preferences–>Keyboard Shortcuts.
• In the Desktop group of actions select the Lock screen entry; the Shortcut field should change to New accelerator...
• Type your desired shortcut, e.g., <Alt>Scroll Lock.
• Click the Close button.

Configure the Screensaver

The Gnome screensaver is named xscreensaver. You can invoke the configuration utility by opening the Actions menu or the main menu and selecting Preferences–>Screensaver; or by entering xscreensaver-demo on the command line.

• Set the Blank After counter to the number of minutes of inactivity before the screensaver takes over the screen.
• Check the Lock Screen After checkbox, and set the counter to the number minutes after the screen is obscured before the computer is locked

There are a number of other settings for controlling the graphics displayed on the screen, etc. For details, click on the Help button or enter man xscreensaver-demo on the command line.

KDE

Activate Screensaver

To activate the screensaver, open the K Menu (the red hat or letter 'K' icon, normally at the bottom left of the screen) and select Lock session; or right click on the desktop and select Lock session, near the bottom of the menu.

Create a Padlock Icon

You can create a padlock icon on the panel, normally at the bottom of the screen, so that you can activate the screensaver with a single click. To do so, right click on the panel at the desired location and select Add–>Applet–>Lock/Logout Applet.

Configure the Screensaver

To invoke the configuration utility for the screensaver, open the K Menu and select Appearance & Themes–>Screen Saver in the index on the left. If you have added the Lock Applet to the panel, you can also right click it to open the configuration utility.

• Check the Start automatically checkbox and set the counter to the number of minutes of inactivity before the screensaver takes over the screen.
• Check the Require password to stop checkbox, and set the counter to the number minutes after the screen is obscured before the computer is locked

There are a number of other settings for controlling the graphics displayed on the screen, etc. For details, click on the Help tab or button (depending on how you opened the utility).

CDE

Activate Screensaver

To activate the screensaver, click on the padlock icon in the middle of the CDE Front Pane, i.e., CDE's toolbar, usually found at the bottom of the screen.

Configure the Screensaver

You can also use the Screen Style Manager found in Desktop Controls to configure the screensaver, including the inactivity timeout. Any changes made here are for the current session only unless you then use the Startup Style Manager to Set Home Session, saving all of the characteristics of the session for the next login.