Oh, I know now. Don't use LVM unless you know what you are doing
I tried anyway...
It was working....

Then I think I messed up my mbr when I was mucking about in Windoze. That's what I first thought.

I'm using grub: now on hda7 aka (hd0,6) - single 8G Hard Drive.
First primary, instead of mbr. <this is new to me>

<<Kewl little tidbit I learned on this endeavour: grub starts counting at 0
so hda7 is (hd0,6) to grub >> --alar takes careful note!!

I have a /boot partition that is ext2fs (I think). How do I double check?
fdisk -l just says Linux.

Don't think grub is the problem as I can still start W2K...

I get an error 16: inconsistent filesystem structure when I try to launch Fedora Core 4.
If I try linux rescue and run grub manually the kernel loads okay.

boot: linux hda=9964,255,63 rescue
chroot /mnt/sysimage
grub
root (hd0,6)
kernel /vmlinux-2.6.11.1.?369_FC4 ro root=/dev/VolGroup00/LogVol00 rh quiet

>> OK

initrd /initrd-2.6.11-1.?369_FC4.img // ? = can't read my writing is that 1 or I ?
rootnoverify (hd0,6)

>> Error 16: Inconsistent filesystem structure

Where do I go from here?

I wish I had taken more notes. Hope there is enuff info for you:
partition/grub/lvm/fedora guru

<alar humbly bows to your expertise>

All ideas welcome.

Many Thanks,
alar

This does not sound like a problem with the MBR. Granted, I don't know much at all about LVM.

Grub comes in pieces. The first piece, stage1 is normally loaded in the MBR. I believe it is in your MBR, but I can't tell for sure from your description. On yours, it well might be in the boot sector of /dev/hda7. This loads stage1.5 (sometimes) and then stage2. Stage2 reads configuration information from menu.lst, and then normally gives you a menu. It is also stage2 that handles the grub prompt. You are clearly getting past stage1.

The error message you are receiving is a stage2. From the grub info page: error.16 Inconsistent filesystem structure
This error is returned by the filesystem code to denote an internal error caused by the sanity checks of the filesystem structure on disk not matching what it expects. This is usually caused by a corrupt filesystem or bugs in the code handling it in GRUB.

You will probably need to use your installation medium or a live CD to run fsck on the volume. Afterwards, you may need to run your installation CD anyways to reinstall the kernel package (including the initrd).

A lot of systems don't have it, but there is a command callec "guessfstype" that will tell you what your filesystem is (this is run from linux, not the grub prompt).

Good luck. Post back with questions (not that I guarantee answers).

I would run a Linux-on-CD distro, such as KANOTIX or Knoppix, and from there check the From there you could do a cat /etc/fstab and see what filesystems have been detected.

fsck led me in the right direction, thanks.

It seems that the /dev/VolGroup00/LogVol00 was okay.

fsck returned that:
LogVol02
LogVol03
LogVol04

were mounted!

umount returned not mounted.

That was my original problem.

The fix was to repartition and to make 100% sure nothing from the
installation would write to a LVM Volume Group!

/
/usr
/usr/local/
swap

are on fixed partitions

/ExtraSpace
/home

are on LVM

In the mean time I got a crash course on grub and with grub:

grub> geometry(hd0)
drive 0x80:C/H/S = 9964, 255, 63, The number of sectors = 160086528, /dev/hda
Partition num: 0, Filesystem fat type: 0x6
Partition num: 4, Filesystem unknown type: 0x7
Partition num: 5, Filesystem fat type: 0xc
Partition num: 6, Filesystem ext2fs type: 083
Partition num: 7, Filesystem unknown type: 0x8e

It seems that grub couldn't detect the LVM

When the install said don't try unless you know what you are doing:
they mean it

Cheers,
alar