[NCLUG] Re: LILO on fragile flies

[Aaron D. Johnson]

In message <20011111022602.42241.qmail at web14105.mail.yahoo.com>, Person Who Asked To Have Her Name Removed From The Internet writes
> i tried both options, and it only now does:
> 
> LILO 21.7-5 boot: win
> Loading win
> _
> 
> then stuck there until hard reboot
>      other=/dev/hdb1
>      table=/dev/hdb
>      label=WIN
> 
> OR
>      other=/dev/hdb1
>      table=/dev/hda
>      label=WIN
> 
> note, after changing lilo.conf i did run 'lilo'
> also note that my boot option is set as follows:
> 
> boot=/dev/hda
> 
> I can still get Linux to boot fine.
> 
> help?

I'll try.

Here's what I'd do.  Recognizing that Microsoft never considered the
possibility that someone would want to put Windows on their second
hard drive, and that Linux doesn't care where you're booting it from
(as long as it can tell where to find its root filesystem), the path
of least resistance is going to be putting Windows on the first drive.
Here's a recipe:

 0) Print all this out.  It will come in handy when your computer is
    off and you need to read it.

 1) Make a note of what device your root filesystem is on.  Running
    the mount command should tell you this, but also try looking for a
    "root=" line in your lilo.conf.

 2) Insert a floppy disk and copy a kernel image to it.  The kernel
    image will be referenced in your lilo.conf file.  A line starting
    with "image=" will end with a filename.  Copy that file to the
    floppy like so:

        dd of=/dev/fd0 bs=9k if=FILENAME

    (Replace FILENAME with the file referenced in your lilo.conf.
    /dev/fd0 should be your floppy drive.  The "bs=9k" thing tells dd
    what size blocks to write out at once.  9K is a single track on a
    standard format 1.44Mbyte floppy and just works well when a floppy
    is what you're writing to.)

 3) Now you'll need to tell the kernel of the floppy what its root
    filesystem should be.  There's a program called rdev that does
    this.  It probably lives in /usr/sbin or /sbin on your machine:

        /usr/sbin/rdev /dev/fd0 ROOTDEV

    Replace ROOTDEV with the root device you discovered in step 1.

 4) Try out the boot floppy.  Reboot the computer with the floppy
    still in the drive.  You may have to fiddle with some BIOS
    settings to get your PC to boot from the floppy.  You'll see a
    message with a bunch of '.'s going slowly by before the normal
    kernel startup messages if the kernel is being loaded from the
    floppy disk.  Also, the floppy light will be on for a while.  You
    shouldn't see a "LILO" prompt.

 5) If Linux doesn't come up, remove the floppy from drive, reboot,
    and send a note to the mailing list.  We'll have to do some
    diagnosis.

 6) If you get this far, congratulations!  You've just
    established that you can boot Linux from a floppy disk.  Next step
    is to make a second Linux boot floppy which can brong Linux up on
    the second hard drive.  Repeat step 2 with a different floppy in
    the drive:

        dd of=/dev/fd0 bs=9k if=FILENAME

    Replace FILENAME with the same thing you used in step 2.

 7) Now, use rdev and to set the root filesystem as the same partition
    on the second disk.  This is pretty simple.  ROOTDEV from step 3
    should have been something like "/dev/hda1", "/dev/hda2", or
    "/dev/hda5" (the number will be specific to your installation).
    ROOTDEV will be the same thing, except replace the "hda" with
    "hdb".  If you used "/usr/sbin/rdev /dev/fd0 /dev/hda1" in step 3,
    use "/usr/sbin/rdev /dev/fd0 /dev/hdb1" this time.

 8) Repeat step 4, trying out the new boot floppy.  You'll probably
    get an error message about not being able to mount the root
    filesystem or being unable to find init.  This is expected and
    shows that you're looking at the other hard drive.

 9) Swap the hard drives around so that the Windows drive is the first
    one and the Linux drive is the second.  There are a couple of
    possible ways to do this.  Either way, you'll need to get a look
    at the jumpers on both of the hard drives and the labels or
    booklets for the drives that say what jumper combinations do what.
    Take note of which drive is plugged in to which connector on the
    IDE ribbon cable and of the jumper settings on both drives.  In
    case this doesn't work out, you'll want to restore them to the way
    they were.

    What you want to accomplish is setting the present "primary" or
    "master" drive to be the "secondary" or "slave" drive and vice
    versa.  If the jumpers on both drives are set to "cable select,"
    you'll just need to swap the drives' positions on the IDE ribbon
    cable and you'll be done.  Otherwise, you'll need to move the
    jumpers around to affect this change.
    
    Make sure everything is plugged back in.

10) Boot the machine with boot floppy number two removed.  If
    everything works out nicely, Windows will come up.  If it doesn't
    put things back as they were before step 9 and send a note to the
    mailing list.  We'll need to figure out what went wrong.

11) Boot the machine with boot floppy number two inserted.  Linux
    should come up.  Possibly with a few error messages you'll fix in
    the next step.

12) Now you need to fix up your /etc/fstab file, which may no longer
    reflect reality.  Make a backup copy of /etc/fstab and change any
    references to /dev/hdaN in the real copy to /dev/hdbN.  These will
    only be located in the first column of the file and may not be
    present at all.

    This is the first point where your hard disks' contents is
    actually changed.

13) Reboot again with boot floppy two still in the drive.  Any errors
    about being unable to mount this or that filesystem should be
    gone.

14) Next, you'll be telling LILO to boot Linux off of the second disk
    instead of the first, and Windows from the first disk:

        # make a backup of /etc/lilo.conf
        cp -p /etc/lilo.conf /etc/lilo.conf.keep

	# Edit /etc/lilo.conf
        # Change lines reading "root=/dev/hdaN" to "root=/dev/hdbN"
        
        # to "/dev/hdbN".  Don't change the "boot=/dev/hda" option.
        # Remove or comment out any "table" lines.
        vi /etc/lilo.conf

        # Run lilo, see if there's any problem
	/sbin/lilo || echo Something went wrong.

    If you're not comforatble with vi, use whatever editor you are
    comfortable with.  When you're done editing, you're Windows
    section should look something like this:

        other=/dev/hda1
            label=win

    You'll get the "Something went wrong." message if lilo thinks
    something didn't work out right.  If that happens, send some mail
    to the list and we'll get you straightened out.  You should still
    be able to boot Linux from floppy and Windows from the hard disk
    if something bad happens.

15) Remove boot floppy two and reboot.  You should be able to do Linux
    and Windows now.  Hopefully.  Booting is probably the most fragile
    aspect of Linux...

Feel free to ask for clarification about anything I've written above
before you try this out.

- Aaron