Compiling kernel 2.4.20/2.4.21 questions.

[Marino Fernandez <mjferna@yahoo.com>]

I've been thinking on compiling my first own kernel for a while, and since 
2.4.21 stable has just been released  I downloaded it and compiled it.... It 
went surprisingly smothly, just a few problems with lilo (wrong names for the 
labels, nothing serious).

My only (kind-off) problem was with /boot/initrd.gz. My debian came from a 
knopix cd, is a mixture  of testing and unstable, had a kernel 2.4.20-xfs 
before (and still has in LinuxOld), has GCC 3.3. 

When I booted into the new kernel, and  /boot/initrd.gz kicked in, there was a 
problem with the modules on it (ext3 and jsb?), that were compiled for 
2.4.20, so I got a kernel panic and the bootup stalled. Then I read that I 
really do not need /boot/initrd.gz (Debian Reference page 85), so I comented 
it out in lilo like this:

image=/boot/vmlinuz-2.4.20-xfs
	label=Linux
	initrd=/boot/initrdold.gz
	read-only
#	restricted
#	alias=1

image=/boot/vmlinuz-2.4.21
	label=LinuxNew
#	initrd=/boot/initrd.gz
	read-only
#	restricted
#	alias=1

So here is my first question. What is /boot/initrd.gz for anyway?. Do I need 
it?.

My second question is about the xfs patch. Before compilation I tried to patch 
another kernel I was playing with, before compilation (2.4.20)... uuuhhh!... 
should I do it after compilation?.  Anyway, I couldn't patch it, I got a 
message stating that the 3 Hunks failed!?!?!. So I left it out for 2.4.21... 
I don't even think there is a patch for 2.4.21, and if there is, somebody let 
me know.... Do I need that patch. I use ext3 only, and I have no plans to use 
anything else.

My third question is... well, so far everything works, my laptop is in one 
piece... but I really do not notice any difference... So, why should I use 
this kernel?. I only did it because my knoppix CD does not come with the 
kernel source that I need to recompile the kernel and get the Dazuko 
"patch/module" I need for  AVguard antivirus.

Finally, how do I get my kernel customized for 686... just to know!.

Thanks.

PD
I guess I should be doing some more reading and googling, but I am a little 
bit tired, so bear with me. Again, thanks.