Clarification needed on Handbook: Tracking for Multiple Machines

D J Hawkey Jr hawkeyd at
Sat Feb 21 09:23:31 PST 2004

On Feb 21, at 05:56 PM, Gabriel Ambuehl wrote:
> DJHJ> Second, two machines are of the same architecture, but they have different
> DJHJ> CPUs: One is an Intel PIII, but the other is a PII. Will the world built
> DJHJ> on a PIII be correct for a PII? Similarly, will the kernel for the PII
> DJHJ> built on a PIII be correct for the PII, given the different variables and
> DJHJ> settings in the two kernel configuration files?
> Just make sure you build for 686. If that doesn't work, make it 586 (I
> think the PI qualifies as 686 but I'm not entirely sure). I think the extensions such as
> SSE etc are detected dynamically and shouldn't cause any problem.
> In all my years of messing with builds, I never run into this problem,
> so I guess it's pretty safe.

Yes, both [my] machines define I686_CPU.

"Dynamically", as in "at runtime"? I think you're right, but I don't
know for certain, either. This is exactly what I'm wondering about;
the PII has only MMX, for instance, while the PIII has SSE and MMX2.

I assume the world's codebase is CPU-agnostic within an architecture,
but I really don't want to assume this; I'd rather know this.

> DJHJ> Finally, after briefly following the makefile chain, it looks as though
> DJHJ> what is written for -CURRENT is backward-compatible to 4.5-RELEASE?
> I don't think it is. 4.5 is OLD. You might not even find 4.9 to be
> backwards compatible to 4.5, much less CURRENT.

Yes, 4.5-REL is old, but I have too much vested in my 4.5-REL systems
to jump anytime soon. I have been maintaining my 4.5-REL systems WRT
post-4.5 security updates (right up to SA-04:02), and for what these
machines are and what they do, 4.5-REL is perfectly suitable.

> DJHJ> /etc/defaults/make.conf doesn't mention KERNCONF; /usr/src/Makefile.inc1
> DJHJ> does. Since /usr/share/mk/ sucks in /etc/make.conf, that should
> DJHJ> propogate KERNCONF to /usr/src/Makefile, right?
> You can also
> just supply it on the command line when doing your make runs.

Yes, but this means individual commands for each machine's kernel, as
opposed to one command for all machines (think "issue command and go to
bed", or even an `at` command). Are you stating definitively that what
I saw in the makefile chain isn't what is really there?


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