First draft:
This document is primarily written as an alternative for those experiencing the lilo 'L 99' error found under LiloNotes.
The guidance here resolves several issues for a specific situation. The configuration is such that we are using an EPIA M-II 10k motherboard with a CDR as IDE0 master and a > 136gb hard drive as IDE0 slave. A linux install is already laid out on the drive, but unaccessable due to boot loader issues.
The EPIA bios is unable to reliably identify the 203Gb drive I'm using; sometimes it will identify as 136gb, other times as 203gb. To resolve this, first go into the BIOS and set the drive to 'Manual' for primary slave.
Despite much documentation on the net regarding using LBA or Large mode, the bios will not reliably detect the disk with these options; the only way to hard code the sectors heads and cylinders is to use CHS. When setting CHS use bios autodetection to ensure the Capacity displayed is correct for your hard drive before saving. In my case that was 203Gb.
Next, boot from a linux ISO or floppy boot disk to get to a root shell prompt. 'fdisk /dev/hdb' followed by 'p' should show your layout. In my case, I had a 512 mb swap partition as /dev/hdb1 and the rest of the disk as a single boot partition called /dev/hdb2.
This is done as follows; 'mkdir /mnt' will make a mount point if not already present.
Next, mount the partition displayed by fdisk, in this case hdb2, as follows: 'mount /dev/hdb2 /mnt'.
Finally, we set this as our root partition for further work. This will make life much easier as we will no longer load binaries from CDRom or floppy with the associated loading delays:
'chroot /mnt bash'
If you prefer ksh, sh, or another shell simply substitute its name for 'bash' in the above command.
We are now root editing our inaccessible system.
'ifconfig -a' will list network interfaces. If you don't see your local interface, either configure it up with 'ifconfig eth0 inet <ip address> netmask <netmask> up' and 'route add -net default gw <gateway>' or use the 'dhclient' command to retrieve an ip address from any local dhcp server.
Documentation can be found at 
http://www.gnu.org/software/grub/. Using debian (or derivatives such as knoppix) I simply typed 'apt-get install grub'.
'grub-install --force-lba --no-floppy /dev/hdb' will install grub and layout the appropriate files under /boot. Under debian 'update-grub' will then build a menu of available kernel images, which can be edited under '/boot/grub/menu.list'. For non debian users typing
grub
followed by
root (hd0,1) setup (hd0)
will install the basic grub bootloader without a menu. In the above example 'hd0' indicates our first hard drive (the cdrom is not included in that scan), '1' indicates our 2nd partition listed under fdisk (hdb2).
Note: grub starts counting partitions from 0, rather than 1, so fdisk hdb1 is grub partition (hd0,0), hdb2 is (hd0,1), etc. Grub also ignores extended partitions, so if you are using any you will need to subtract an additional 1 from the count.
So far, so good - but what if the partitions you wish to boot are above the 136gb mark? At this point grub will give you 'Error 18', the bios does not support the cylinder that partition is present on.
To avoid this error, I repartitioned my drive as follows:
First, I stole 40mb from my swap partition to make a 'boot' partition within the first 1024 cylinders of the disk, those supported by the BIOS. To ensure no configuration changes were required, I did the following:
/dev/hdb3 /boot ext3 defaults 0 1
Note: 'hdb3' will only be correct if you created your new boot space as partition three during the fdisk operations.
mount /dev/hdb3 /mnt cd /boot find . | cpio -pdv /mnt umount /mnt rm -rf *
Be very careful to ensure you only type the rm -rf command while still under the /boot directory, and that all the files successfully copied during the cpio stage.
At this point, either 'update-grub' under debian or 'system (hd0,2)' using the 'grub' command will set grub to boot off your new boot partition to load the kernel, allowing OS images to be above cylinder 1023.
Once again, edit your menu.lst file to ensure your OS entries list the correct partitions for the actual operating system images.
An example follows:
title test, kernel 2.6.13.2-chw-3 root (hd0,2) kernel /vmlinuz-2.6.13.2-chw-3 root=/dev/hdb2 ro savedefault boot
This line will provide a grub menu option titled 'test, kernel 2.6.13.2-chw-3' located on our new boot partition (hd0,2) (hard disk 0, fdisk partition , which we just created). Once located the kernel will be loaded with the line 'root=/dev/hdb2', telling it to find the rest of the operating system under linux hard disk hdb2. If you wish to create subsequent OS images to test other distros, os's or builds on, the kernel is simply loaded with a different root= argument.
Fdisk example:
The commands for fdisk are shown below:
fdisk /dev/hdb The number of cylinders for this disk is set to 24792. There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Command (m for help): p Disk /dev/hdb: 203.9 GB, 203928109056 bytes 255 heads, 63 sectors/track, 24792 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/hdb1 1 65 522080+ 82 Linux swap / Solaris /dev/hdb2 66 23432 198619627+ 83 Linux Command (m for help): d Partition number (1-6): 1 Command (m for help): n Command action l logical (5 or over) p primary partition (1-4) p Selected partition 1 First cylinder (1-24792, default 1): 1 Last cylinder or +size or +sizeM or +sizeK (1-60): 60 <-- note we have reduced the cylinder count here by 5 Command (m for help): n Command action l logical (5 or over) p primary partition (1-4) p Selected partition 1 First cylinder (1-24792, default 1): 61 Last cylinder or +size or +sizeM or +sizeK (1-60): 65 Command (m for help): t Partition number (1-6): 1 Hex code (type L to list codes): 82 Changed system type of partition 1 to 82 (Linux swap / Solaris) Command (m for help):w partition written to disk Command (m for help): q
But... other distros? Our whole disk is eaten by hdb2. Well, ext2 and ext3 filesystems can be resized without losing data. To do so use the 'resize2fs' command; if your partition is ext3 you will need to disable journaling with the 'tune2fs -O ^has_journal /dev/hdX' command first, use resize2fs to shrink your disk spanning drive, then re-enable it once done using 'tune2fs -j /dev/hdX'.
Once resized use fdisk to delete the old partition data and recreate it starting at the same cylinder but finishing just above the new end point. This can be calculated by the following method:
(number of cylinders reported in fdisk) / (old size in blocks reported by 'fsck.ext2 /dev/hdb2') = cylinders per block (new size in blocks reported by 'resize2fs /dev/hdb2 <size>') * (cylinders per block) = size of new partition in cylinders
So:
Note: this MUST be done with the drive unmounted - once again, boot off your cd or floppy, and work on the drive unmounted.
With your boot partition in the first 1023 cylinders as outlined above it is perfectly possible to place your subsequent OS layouts in extended partitions anywhere on the disk.
Create a new extended partition as partition 4, then divide up the space amongst as many drives as you like. I made two 5gb partitions for a 'stable' and 'test' OS image, while keeping /dev/hdb2 simply as a 'data' partition for my home directories and PVR recordings.
Once resized, my filesystem looked as follows:
Fdisk:
Disk /dev/hdb: 203.9 GB, 203928109056 bytes 255 heads, 63 sectors/track, 24792 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/hdb1 1 60 481918+ 82 Linux swap / Solaris /dev/hdb2 66 23432 187695427+ 83 Linux /dev/hdb3 61 65 40162+ 83 Linux /dev/hdb4 23433 24792 10924200 5 Extended /dev/hdb5 23433 24112 5462068+ 83 Linux /dev/hdb6 24113 24792 5462068+ 83 Linux
/etc/fstab for /dev/hdb6:
# filesystem mountpoint type options dump pass /dev/hdb6 / ext3 defaults,errors=remount-ro 0 1 /dev/hdb3 /boot ext3 defaults 0 1 /dev/hdb2 /data ext3 defaults 0 2 /dev/hdb1 none swap defaults 0 0 proc /proc proc defaults 0 0 sysfs /sys sysfs defaults 0 0
/boot/grub/menu.lst:
default 0 timeout 5 color cyan/blue white/blue title stable, kernel 2.6.13.2-chw-3 root (hd0,2) kernel /vmlinuz-2.6.13.2-chw-3 root=/dev/hdb6 ro savedefault boot title stable, kernel 2.6.13.2-chw-3 (recovery mode) root (hd0,2) kernel /vmlinuz-2.6.13.2-chw-3 root=/dev/hdb6 ro savedefault boot title test, kernel 2.6.13.2-chw-3 root (hd0,2) kernel /vmlinuz-2.6.13.2-chw-3 root=/dev/hdb2 ro savedefault boot title test, kernel 2.6.13.2-chw-3 (recovery mode) root (hd0,2) kernel /vmlinuz-2.6.13.2-chw-3 root=/dev/hdb2 ro single savedefault boot
/boot/grub/device.map
(hd0) /dev/hdb
Any questions, I'm at matt at clues dot com ;)
