No Trust to X

Ctrl+Alt+<Keypad *>  - this is all you need nowadays to bypass screen lockers in X Server. Although, I believe, this flaw will be fixed pretty soon, the trust is lost for ever, and I'm going back to roots by switching to X-independent "vlock".

"sudo vlock -na" works even when called from X, and seems to be the most secure way to lock your machine, since virtual consoles are handled as well. 
 (Make sure you remember root password before executing the above command.)

Beyond Brightness and Contrast

When you occasionally open advanced display properties on your PC you might notice there is a tab for controlling gamma parameters. I was always curious why gamma controls might be required and more importantly how to use them properly. Despite this fact I never had enough courage to get my teeth into the topic until today...

Leaving aside a boring story of what finally pushed me beyond brightness and contrast monitor controls I just want to promote an excellent tutorial by Norman Koren on monitor calibration and gamma.

Linux users might want to start with Monitor calibration under X article at linux.com which originally led me to the Norman's site.