Fixed modular kernel path and different kernels

[Thomas Klausner <tk%giga.or.at@localhost>]

Hi!

One issue that made me avoid modular kernels is that updating is
finickier.

When you switch from one modular kernel to another, you have to
replace /netbsd and /stamd/amd64/${VERSION}/modules.

So for example, when testing two different kernels of the same
-current major version, you can not just boot /netbsd.old, but you
have to replace /stamd/amd64/${VERSION}/modules with the old modules
before rebooting. That can be a problem if a module is completely
broken due to a bug. So you need to always have a reliable kernel of a
different NetBSD version available.

Other systems handle this differently.

One example is having a directory that contains the kernel _and its
modules_. Then you can easily switch between two different kernels
even of the same NetBSD version by just choosing the other directory.

Perhaps there are other, even better solutions. My point is, we should
switch away from our current method.

Am I overlooking something?
 Thomas