NOW YOU SEE IT...GRUB'S MYSTERIOUS DISAPPEARING ACT

[alarmcall]

Hello and welcome to the Twilight Zone.

First of all I apologise for the length of this post, however I feel it is better to explain exactly what I've done in one post rather than re-posting with extra detail.

I am using a Asus A7V600-X mobo with and Athlon XP2500+ CPU, 512MB DDR ram and a 120GB Seagate barracuda (PATA). The mobo uses the via KT600 northbridge and the via vt8237 southbridge. The kernel option VIA82Cxxx under the drivers menu covers this chipset (Ibelieve).

So, last week(!) I started to install Gentoo 2004.1 (Stage 3). It took me quite a while, but carefully following the handbook I did it. Just when I thought that everything was going smoothly I hdparm'd /dev/hda to find DMA wasn't on. Despite my best efforts and days worth of re-building the kernel with various combinations of options compiled I just couldn't get my numbers up. And yes I did try:

# hdparm -d1 -c1 -m16 /dev/hda

and got back (time and again):

HDIO_SET_DMA failed: Operation not permitted

After scouring this forum and the web I found that many people with the via8237 southbridge have had just this problem and most had fixed it by changing the kernel version. Having installed 2.6.5 I decided to "upgrade" to 2.6.7 (thinking that I would be patching the original kernel...) To do this I (erroneously?) typed:

# emerge gentoo-dev-sources

It took hours to compile and build but then it finished and I had gentoo-2.6.7-r8 in /usr/src. Clearly I hadn't patched the original kernel, but downloaded a complete kernel to version 2.6.7. As an aside does anyone know how you patch a kernel using emerge (if it can indeed be done)? Or do you have to patch by downloding the tarballs and use the patch utility?

Thankful that I hadn't buggered the box I then typed make menuconfig and started to scroll through the screens and options. To my surprise I found that the original options I had made when compiling the kernel were present in the current kernel. I then saved the kernel "changes" and compiled. I copied the relevant files (as per the handbook) over to /boot and edited grub.conf to include this new kernel as an option in the boot menu.

This is the interesting bit. I then rebooted, but upon selecting the new kernel version I got an error:

root (hd0,0)
kernel /kernel-2.6.7-gentoo-r8 root=/dev/hda2

Error 15: File not found

The original kernel still boots (thankfully). However, when I get to the prompt and cd to /boot the grub directory and grub.conf are MISSING! I can do

# emerge -pl grub

and it comes back with:

[ebuild R ] sys-boot/grub-0.94-r1

if I:

# emerge grub

I get grub back in /boot and it includes my original grub.conf!!! Does anybody know what I've done wrong?

Was I naiive to try and build a new kernel in the way I described and then attempt to "dual boot" with the 2 different kernels?

To add insult to injury I still can't find the reson for not being able to turn DMA on my hard disc (answers to this question also gratefully received )

Many thanks in advance for any help you are able to offer - this has been foxing me now for days and I'm getting that sinking feeling...!!!

[moocha]

The reason for this is that, according to the handbook, you created /boot as a separate file system on a separate partition. That file system, also according to the handbook, is not mounted by default when booting (which is a very good thing, as it's not needed when running the system, and avoids accidents a la rm -rf). But when you want to edit grub.conf and/or want to place new files (kernel images and whatnot) into /boot you'll have to do

[alarmcall]

Hi moocha - thanks for the quick reply!

I now understand! It seems like such an elementary thing and yet I hadn't thought of it (which I suppose shows how green I really am with respect to the Linux OS!) However, making such stupid mistakes will not stop me from mastering this thing - I'm enjoying (mostly!) the experience.

I have managed to boot using the new kernel, although I still cannot work out how to set DMA on my hard disc - any words of wisdom on that one?

Thanks again for your time - you have helped me learn a valuable lesson today!

[moocha]

Most welcome, and don't let mishaps like this deter you (especially since there's no harm done ).
BTW, you might want to unmount /boot and look at what got placed there ending up on the root file system instead on the /boot one (when /boot is unmounted anything placed into /boot is part of the / file system).
Other than that - happy it worked out, and have fun with Gentoo
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