Re: [Jeff Garzik <address@hidden>] Re: ack! grub bug...

[OKUJI Yoshinori]

From: Pixel <address@hidden>
Subject: [Jeff Garzik <address@hidden>] Re: ack! grub bug...
Date: Wed, 21 Feb 2001 23:40:39 +0100 (CET)

> It works around a kernel bug.  That is wrong in and of itself.
> A kernel bug fix belongs in the kernel, not in grub.

You're just talking about an utopia. Because Linux was (is?) poor at
memory detection, people wanted GRUB instead of Linux to probe memory.
IMO, most of the code of any boot loader is wasted for workarounds,
because of stupid kernels, buggy BIOSes, and so on...

> Newer machines have several regions of reserved memory outside and
> inside these regions.  grub's actions are suicide on newer laptops,
> and machines like servers with lots of memory.  Laptops have special
> sections of memory above 1MB which must be reserved... Ditto for
> ACPI tables.  Using mem=XXX completely eliminates any information
> that the BIOS has provided to the OS.

That looks like a failure in Linux's kernel parameter scheme. The mem=
option was designed for older PC architectures, so the real evil is
the option itself. In fact, if you want to limit the size of memory
used by Linux, you need to specify the option anyway, and Linux will
hang up. This means that the problem is in Linux rather than in GRUB.

> Grub cannot do this on kernel 2.4, and probably should not do it on
> kernel 2.2.  I must check for kernel 2.2... I think the 2.2 bug is
> fixed.  Definitely not for 2.4.  It makes the kernel unstable to do so.

And, the Linux bootstrap interface never provide the version number of
the kernel itself, so GRUB can do nothing, whether you use Linux 2.2,
2.4, or 2.0. Note that Linux 2.0.x and older Linux 2.2.x are still in
use, so we shouldn't disable the automatic passing of the mem= option.

IMO, that problem should be fixed in Linux rather than GRUB. And, the
command "kernel" supports the option `--no-mem-option' so that you can
specify that GRUB shoulnd't pass the mem= option automatically,
anyway. *sigh*

Okuji