On Sunday, October 21, 2012 04:14:17 AM Lisi wrote:
> We advise studying the README files in this root directory of the kernel
> source, and Documentation/Changes or the documentation index of the kernel
> in Documentation/00-INDEX.
> Presumably I have to download a kernel source to get at the README, but
> where can I find the Documentation/00-INDEX?
> If I download an older kernel than the one that I am using, in oredr to
> read the README file, will GRUB continue to use the present newer kernel?
> I am still not very confident about editing GRUB 2.
> And yes, I have googled - and I'm afraid that I found the answers as clear
> as mud. :-(
When you unpack the kernel *source*, it will create a tree (such as linux-18.104.22.168). In there, you will find README and Documentation/, among other things. Under Documentation/, you will find 00-INDEX and many squirrels.
Debian's kernel source package may be unpacked in /usr/src (or somewhere under there). I don't know; it's been a long time since I unpacked a Debian kernel source deb. (All my build work these past few years has involved vanilla kernels from kernel.org.) It's fair to assume that Debian don't change the kernel source tree structure.
Downloading any Debian source package should not alter the running system's behaviour. And DLing/unpacking a kernel source definitely won't change the system's boot; you have to take deliberate steps to make grub boot a new custom-built kernel. (Source packages are quite different from regular 'built' packages.)