Ok. So I'm a little fresh in here and in linux generally. Maybe this topic has been answered before, but I'll try anyway..

In the XF86 Config-4 file, what does lines like these mean?

Modeline "800x600" 40.12 800 848 968 1056 600 601 605 628 #60Hz
Modeline "1024x768" 75 1024 1048 1184 1328 768 771 777 806 -hsync -vsync
Modeline "1024x768" 85 1024 1056 1152 1360 768 784 787 823
ModeLine "1152x864" 65 1152 1168 1384 1480 864 865 875 985 Interlace
Modeline "1152x864" 92 1152 1208 1368 1474 864 865 875 895
Modeline "1152x864" 110 1152 1240 1324 1552 864 864 876 908

Well I have an idea, but how the h&%% can I obtain these numbers for my crt screens? Can't find it anywhere! I'm trying to set up a twinview system in mandrake 10.0.

And..

Can I harm my screens by applying the wrong values?

If someone has a good XF86Config-4 file that works with twinview, fell free to post it. Could be of good help, thanks