Grub on floppy

[Phil Schaffner]

On Fri, 2005-05-20 at 09:49 -0400, Bill Case wrote:
> Hi;
> 
> I have been playing with this for three or four days and still haven't
> got it right.  Any help would be appreciated.
> 
> I run Fedora on my own basement machine.  I have installed Ubantu on my
> wife's WindowsXP upstairs - with her very grudging permission.  Family
> diplomacy suggestes that I do not make her machine a dual boot. (Dual
> booting would just serve has a constant reminder that I have been
> screwing around with her machine.  Any time something goes wrong it will
> be Linux's and consequently my fault.)
> 
> What grub files should I but on a floppy to give me a dual boot into her
> system? I would use the floppy as sort of a key.

Have done this for my wife and kids for some years now.  [Fortunately,
they have all pretty well outgrown the need for the boot floppy, and all
use both OSs.  Still haven't gotten to the state where I can blow away
the Evil Empire OS due to games and one or two apps the wife won't give
up.]  I use the script below (as root) and edit the grub.conf file on
the floppy to change the default stanza to boot.  Your case may be a bit
harder as you don't seem to have a dual-boot grub setup to start from,
as the script expects.  Would need much more detail on the system to
help create the correct grub.conf stanza[s].  Hope studying the script
will give a clue or two.

> Will I still want or
> need /root?

Don't quite understand the question, but don't think you can live
without /root which is root's home directory.

> Is there a way that I can get to the Linux on her system
> while I am on my own Fedora downstairs?

Yes - ssh will get you there - assuming it is booted under Linux, and
the machines are networked, wired or wireless.  [Don't really think you
want to get into Cygwin with the sensitivity to messing up the spouse's
system, so won't go there.]

> Are any of you married?  Can I really get into big trouble doing this?

Yup.

Good luck,
Phil

------------------------ Cut Here -----------------------
#!/bin/bash
# mkgrubmenu
#
# Written by Phil Schaffner <p.r.schaffner at ieee.org>
#  based on mkbootdisk by Erik Troan <ewt at redhat.com>

pause=yes
format=yes
device=/dev/fd0
unset verbose

GRUBDIR=/boot/grub
MOUNTDIR=/tmp/mkgrubmenu
PATH=/sbin:$PATH
export PATH

VERSION=0.2

usage () {
    cat >&2 <<EOF
usage: `basename $0` [--version] [--noprompt] [--noformat]
       [--device <devicefile>] [--grubdir <dir>] [--verbose -v]
       (ex: `basename $0` --device /dev/fd1)
EOF
    exit $1
}

while [ $# -gt 0 ]; do
    case $1 in
	--device)
	    shift
	    device=$1
	    ;;
	--grubdir)
	    shift
	    GRUBDIR=$1
	    ;;
	--help)
	    usage 0
	    ;;
	--noprompt)
	    unset pause
	    ;;
	--noformat)
	    unset format
	    ;;
	-v)
	    verbose=true
	    ;;
	--verbose)
	    verbose=true
	    ;;
	--version)
	    echo "mkgrubdisk: version $VERSION"
	    exit 0
	    ;;
	*)
            usage
	    ;;
    esac

    shift
done

[ -d $GRUBDIR ] || {
    echo "$GRUBDIR is not a directory!" >&2
    exit 1
}



if [ -e "$device" ]; then {
    [ -n "$pause" ] && {
	echo -n "Insert a"
	[ -n "$format" ] || echo -n " vfat formatted"
	echo " disk in $device."
	echo "Any information on the disk will be lost."
	echo -n "Press <Enter> to continue or ^C to abort: "
	read aline
    }

    [ -n "$format" ] && {
	[ -n "$verbose" ] && echo "Formatting $device... "
	fdformat $device || exit 0
	mkfs.msdos $device > /dev/null 2>/dev/null || exit 0
	[ -n "$verbose" ] && echo "done."
    }

    rm -rf $MOUNTDIR
    mkdir $MOUNTDIR || {
	echo "Failed to create $MOUNTDIR" >&2
	exit 1
    }
    [ -d $MOUNTDIR ] || {
	echo "$MOUNTDIR is not a directory!" >&2
	exit 1
    }

    mount -wt vfat $device $MOUNTDIR || {
	rmdir $MOUNTDIR
	exit 1
    }

    mkdir $MOUNTDIR/grub

    [ -n "$verbose" ] && echo -n "Copying $GRUBDIR files... "
    cd $GRUBDIR
    cp -a stage1 stage2 grub.conf device.map $MOUNTDIR/grub
    [ -n "$verbose" ] && echo "done."

    [ -n "$verbose" ] && echo -n "Setting up GRUB... "
    grub --device-map=$MOUNTDIR/grub/device.map --batch <<EOF
root (fd0)
setup (fd0)
quit
EOF

    [ -n "$verbose" ] && echo "done."

    umount $MOUNTDIR
    rmdir $MOUNTDIR
    [ -n "$verbose" ] && echo "done setting up GRUB."
    echo "edit (fd0)/grub/grub.conf to customize."
}
else
    echo "$device does not exist"
fi