Boot Disk

[Phil Schaffner]

On Thu, 2004-02-05 at 15:29, Terry Polzin wrote:
> On Thursday 05 February 2004 14:43, Michael Gargiullo wrote:
> <snip>
> > I just need to boot the OS to be able to run grub-install  /dev/sda
> 
> Boot from install CD into rescue
> mount the installation
> 
> chroot /mnt/sysimage
> grub-install [ /dev/hdx] [/dev/sdx]
> 
> That should get grub working.  But as I have stated in other replies.
> A working boot medium is needed for situations like you mentioned, less messy 
> and needed if you don't want a boot loader.

If you want a floppy solution for GRUB/MBR problems, or just to change
default boot OS by popping in a floppy, the following script may be
useful:

####################################################################
#!/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 "$verbose" ] && echo -n "Setting up GRUB... "
    grub --device-map=$GRUBDIR/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
####################################################################

Phil