Re: any reasons to recompile kernel?

On 7/22/05, Maurice Ling <[email protected]> wrote:
> My question comes from reading "Building XNU" in OpenDarwin HOWTOs,
> http://www.opendarwin.org/en/articles/building_xnu/. It barely provides
> the steps of obtaining the tool chain and the basic steps of compiling
> the kernel but nothing on kernel configurations. So it is hard to see in
> what circumstances where a compile is warranted.

Apple has more recent documentation at
<http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgramming/build/chapter_18_section_1.html>.

> I do have a different but related question here. This is also related to
> the thread on "building xnu for osx",
> http://lists.apple.com/archives/darwin-development/2001/Apr/msg00322.html,
> hence, the cross-posting. My apologies if anyone do take offense in
> this. From that thread and the HOWTO, it does seems that it is possible
> to build a Darwin 8 kernel (corresponding to OSX 10.4) and replace the
> Darwin 7 kernel in OSX 10.3.

I don't know how you got that impression from the message you refer to
or the HOWTO. It is certainly not the case.

> Besides masochism or in the name of
> experimentation, I cannot think of a reason why someone will want to
> build the same kernel as in their working system and install it at great
> risk.

If you are extending/modifying the kernel's behaviour. As Kevin said,
if you don't know that you need to recompile the kernel, you don't
need to recompile the kernel.
 
> A very specific question will be this: if I do not care about user
> add-ons like widgets etc etc, but I want to install Java 1.5 into my
> "OSX 10.3", is kernel compilation and installation of Darwin 8 a way to
> get there?

J2SE 1.5 is only available for Mac OS X 10.4 Tiger. It almost
certainly depends on Tiger-only functionality across the board.
Replacing arbitrary components of Mac OS X with those from a different
major release of OS X is a recipe for disaster.

The way to get there is to buy Tiger.

 -- Finlay