OOOOOOK. I'm upgrading to 2.6.7 ... From 2.4.20
I'm also switching from Devfs to Udev.
I add the correct boot options to grub
I have a PCI SCSI controller.

So grub's entry looks like:

title Linux 2.6.7
root (hd0,1)
kernel /boot/kernel-2.6.7 doscsi root=/dev/ram0 gentoo=nodevfs real_root=/dev/sda3 init=/linuxrc hda=ide-scsi
initrd /boot/initrd-2.6.7-testing

Now the problem... Real root has been every device I can think of that might possibly be the third partition on the scsi hard drive. Well what seems to be happening is that udev finds the scsi devices but I can't mount root. I have all the filesystem support i can cram into the kernel in there so it baffles me. Basically it rockets through actually detecting and installing the scsi device and various others and then i get this "Error lstat(2)ing md1..." ... md2 ... md3 etc until md255. then I get "Determining root device..." "Mounting root device..." and it freezes. I've noticed if I change the real_root to something completely obserd I can get into a shell or type in the root device that's correct, so apparently it sees sda3 and thinks it's the right partition only it can't mount it. WTF mate? I'm really at a stopping point if anyone could give me something to fish for answers in that would be highly useful...

I get the same "Error lstat(2)ing ..." /dev/md/* message ever since I added RAID support to the kernel (rather than as modules). I thought it was devfs weirdness for the RAID autodetection. But, although it's annoying, it doesn't interfere with my boot process, so I'm guessing that isn't your problem. Sounds like it's a GRUB issue.

I'm no GRUB expert, but I've worked through some problems with GRUB detecting drives. Maybe your "root (hd0,1)" in grub.conf is correct, but to be certain I'd make a GRUB boot floppy and install natively.

I think part of my trouble was that my 'root' partition for GRUB (where the kernel images are stored) wasn't on the primary hard drive (where GRUB was installed). The native install method shines here. Boot the GRUB floppy, then find where your BIOS sees your kernel images, set that as root for GRUB and then re-install GRUB.

So the confusing part is that there seems to be a root for GRUB (which is your /boot), and then there's a root for your Linux system. The native install might help you here; verify the GRUB/BIOS name for your /dev/sda3 by typing "find /bin/ls" (or any file that you know to be on /dev/sda3) at the grub> prompt, then set your grub.conf root to that BIOS name.

Good luck.

Chaz