I got very curious about GRUB and HURD when my laptop crashed when power went down. I found out that GNU has developed it's own kernel for UNIX like OS which is different than any Linux Distros. uses. It is called 'HURD'.
Both are two different kernels.
You can find kernel image for Linux at www.kernel.org
and GNU kernel at http://www.gnu.org/software/hurd/
The Hurd and Linux:
People sometimes ask, ``Why did the FSF develop a new free kernel instead of using Linux?'' It's a reasonable question. The answer, briefly, is that that is not the question we faced.
When we started developing the Hurd in 1990, the question facing us was, ``How can we get a free kernel for the GNU system?'' There was no free Unix-like kernel then, and we knew of no other plan to write one. The only way we could expect to have a free kernel was to write it ourselves. So we started.
We heard about Linux after its release. At that time, the question facing us was, ``Should we cancel the Hurd project and use Linux instead?''
We heard that Linux was not at all portable (this may not be true today, but that's what we heard then). And we heard that Linux was architecturally on a par with the Unix kernel; our work was leading to something much more powerful.
Given the years of work we had already put into the Hurd, we decided to finish it rather than throw them away.
If we did face the question that people ask---if Linux were already available, and we were considering whether to start writing another kernel---we would not do it. Instead we would choose another project, something to do a job that no existing free software can do.
But we did start the Hurd, back then, and now we have made it work. We hope its superior architecture will make free operating systems more powerful.