Booting with different kernels -- what am I missing?

[Doug Sutherland]

 > I thought that the kernel was independent from the software
 > running on a particular machine.

Considering that the kernel provides access to all of the
hardware, this not true. The hardware drivers are a moving
target, drivers change, and methods change. For example there
is the old method of using mknod for devices, then there was
devfs, in the future there will be udev.

 > I know that a person runs some distribution, then often
 > downloads later kernel source, recompiles it and everything
 > is fine.

Yep.

 > I thought I'd start by doing something simpler. I simply tried
 > to boot Slackware 8 with a speakup-enabled slackware 9 kernel

This almost never works. The loadable kernel modules won't match
along with other stuff. When the kernel boots it tries to find
its needed modules in /lib/modules, and they won't be there.

 > 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?

You should be able to boot a slack9.1 system with a slack8 boot
disk, provided you specify something like this at the first prompt

mount root=/dev/hda2 ro

You need to specify your root partition.
I noticed that the command to do this changed in the 9.x series,
I think you now need to specify noinitrd or something like that,
read the BOOTING.TXT file in slackware, and the boot disk will
usually say something like this: you can boot your linux system
in a pinch by doing this (follow those instructions). I guess its
a chicken and egg scenario since linux isn't loaded yet so no
speakup.

   -- Doug