Screensavers for security
Tip 73 was about using a password to stop people from starting up your computer. Once your computer’s up and running though, if you leave it unattended it’s wide open to anyone who wants to mess around with it.
Many years ago computer screens were manufactured in such a way that after prolonged use the screen could “burn in” where it constantly showed the same image. If you look at an old MacPlus, for example, you can probably see a faint image of the Menu Bar, even when the computer’s turned off. [[ using a password]]That’s when companies started producing screensaver software (so named because it was intended to save your screen from such damage). If your computer was idle for a few moments it would start displaying images of flying toasters or other similar attractive or amusing pictures.
Modern Macs come with screen saving software built in, but under OS X it has the added advantage of allowing you to set a password. That means: if you walk away from your computer, after a few moments the screensaver starts up and hides whatever’s on screen behind attractive pictures.
In order to get back to work you simply need to type a key or move the mouse. If a password’s been set then you’ll be asked to enter the password before you can see what’s on screen.
With OS X: go to System Preferences (under the Apple Menu) and click on the Screen Effects pane.
From the Screen Effects list choose Forest or Cosmos, or whichever effect you like. Now click on the Activation tab and choose how long a delay to set and whether or not a password is required.
Use the Hot Corners tab to allow you to easily start the screensaver going or to prevent it from kicking in (I often need that when I’m writing as I have long spells of thinking while reading the screen). Click once in a corner to make a check mark which activates the screensaver. Or click a second time to change it to a minus sign which means moving your mouse to that corner will prevent the screensaver from activating.
Under OS 9: it’s interesting that after using OS X for about 8 months I’m starting to lose track of what you can do with OS 9. Before I started writing this Tip I was certain that OS 9 offered a screensaver / password combination, but it turns out that the password lockout facility works a little differently under OS 9.
The Energy Saver Control Panel will simply dim the screen after a certain period, but doesn’t allow for a password.
To set up password protection on a running computer you first need to go to the Multiple Users Control Panel (under the Apple Menu) and select the User who should have a password (there may be only one user anyway).
Now click the button called Options, and make sure the Login tab is at the front. Check the box called “If the user is idle for” and select a number of minutes, and then check “Lock the Screen”. Then click the Save button.
Now you’ll see a warning that you need to either log out or restart the machine before the changes take effect.
Once you’ve done that you’ll find that after the machine has been idle for the length of time you’ve specified the screen will turn black and you’ll have to enter a password to get back to work.
With both methods (OS X and OS 9) you need to choose your length of time carefully: too short and the lock-out or screensaver will kick in while you’ve paused to sip coffee or take a phonecall, too long and your computer will be wide open to all comers any time you get up to stretch your legs or answer the door.