Booting with different kernels -- what am I missing?

[Debee Norling]

I have another booting problem but I think it is caused by my
mis-understanding of something. Maybe some of you good explainers can make
this clear for me.

I thought that the kernel was independent from the software running on a
particular machine. I know that a person runs some distribution, then often
downloads later kernel source, recompiles it and everything is fine.

I thought I'd start by doing something simpler. I simply tried to boot
Slackware 8 with a speakup-enabled slackware 9 kernel, and later I tried to
use a slackware 8 boot disk after I'd installed 9.1 on my hard disk. In both
cases, I couldn't boot. I got a kernel panic (which speakup read fine.) Why?

--Debee