For DKMS see: http://linux.dell.com/projects.shtml
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I can't tell you how it works, but I know that the Mandriva 2006 install I use has it installed. Exactly what differences it makes ? The only thing that I have noticed is that if I see a new kernel version available for install, it seems that instead of having to re-install (recompile ?) the nvidia driver manually(which is what I used to have to do) it seems to work it all out i.e. I just install the new kernel version and the DKMS seems to adapt (make work) the nvidia driver.
I'm sure it does other things as well, but as yet haven't worked out what they are.