[tlug] how filesystem works?

[Michal Hajek <hajek1@example.com>]

Hello, 

* Sigurd Urdahl (sigurdur@example.com) [070329 14:53]:
> [...different kernel images...]
> because they might very well reside on different parts of the disk.
> The old kernel might be within the first 1023 blocks, while the new
> one could be somewhere above that.

well, this makes a perfect sense to me. I would like to verify that, but
I do not know how. Any ideas? 

> If your BIOS allows you to I believe you could redefine the disk 
> geometry to have less cylinders. From the top of my head I don't 
> remember how you best could do that, but if you're lucky it's an option 
> in your bios for changing the geometry.

Sounds a bit scary, but I am an adventurer :) Anyway, before this, the other
option is more appealing to me for the moment:
 
> Another way of doing it is getting the new kernel moved to a location 
> earlier on the disk, but that is probably not a trivial operation..

Why is that? Why simply
1. find files at the beginning of disk
2. move these files to the end of disk
3. move kernel image to the beginning of disk

won't work? Is that because I cannot tell to which place on disk the file
will be copied? Or even it is not easy to tell where the file *is*? 
This should not be a principal problem, or should it?

What is the heuristic of mv command? More explicitedly: What if I
"defrag" filesystem (which is ext3 in my case) and than do [1-3] with
assumption, that kernel image will be moved closer to the beginning of
disk as a result of mv heuristic?

I do this more because I would like to understand how these things work
more than an actual problem. 

Best regards
Michal