Question!

I have several distros on my box and I am always adding things. Well, my questions is that I see in the /boot/grub/menu.lst there are all my different distros aand kernel version for each, but there is always just one System.map in the /boot. How is this created(i know that it is created during kernel compilation but what is it for?) and say if I were to install a distro like Linux from scratch should I replace the System .map that I compiled from that version of the kernel. The reason I am asking is that I have noticed oddities with my hardware. Like cdroms not showing up in the dev directory and I was thinking that it had to do with the system.map.

If I use the System.map from the latest kernel on whatever distro, is that backwards compatible with my other distros with prior kernel versions?

Thanls in advance!

When you copy over your System.map after each compilation, you're supposed to rename it just like you do with the kernel (i.e. kernel-2.6.5-gentoo and System.map-2.6.5-gentoo). If it's working fine so far, maybe it's not that big of a deal, but I would suggest doing this with every distro you compile from now on.

That sound logical. So if I rename it then how does my kernel know what one to use? Is there a pointer somewhere that I should also change?

Thanks.

Well, in the grub.conf you specify which kernel to use... if your System.map has the same ending on it (notice my example in the last post) the system would know that way.

Although if you have multiple kernels with different filenames, only one System.map, and everything is working fine, then I'm thinking it's not that important.

OK I did some googling and found that in fact it is best to have System.map-2.x.x for each kernel. I also found that this is the reason why some of my hardware is not working under different kernels. The system.map addresses out symbols. Which can reference different hardware mem locations etc..

So If any anone ever searches this thread out! Everytime you compile a kernel you should add -(whatever is after your kernel)

Example:

vmlinuz-2.4.22-1.2115.nptlsmp
System.map-2.4.22-1.2115.nptlsmp

Have Fun!